In a dot matrix print head drive method for controlling head drive signals for driving dot pins in accordance with print pattern signals, a correction factor is set specifically to each dot pin; and the length of time for which the print pattern signals are to remain in effects is varied according to the correction factor, to correct the drive time for each dot pin.

This invention concerns a method for driving dot matrix print heads in serial dot matrix printers for printing characters and graphics responsive to data transmitted from data processing equipment.
In a serial dot matrix printer, dot printing is made while the dot matrix print head is moved by a space motor, and linefeed is made by a linefeed motor. Characters and graphics are printed by repeating these operations. Of these operations, the drive of the dot print head affects the resulting print quality and print speed.
FIG. 1 is a block diagram of a dot print head control circuit in which the conventional dot print head drive method is applied. FIG. 2 is a timing chart illustrating the operation of the components in FIG. 1. In these figures, 1 denotes an instruction circuit, 2 denotes a drive time signal generation circuit, 3 a drive circuit, and 4 a dot print head.
Instruction circuit 1 is comprised of a microcomputer. For each timing signal a, instruction circuit 1 sets print pattern signal b (#b1, #b2, . . . , #bn, where n is a dot pin number) to high level "1", corresponding to the dot pins in dot print head 4 to be actuated for printing, and transmits the signals to drive circuit 3; at the same time, instruction circuit 1 transmits drive signals c, which have different effective time values depending on the number of dot pins energized, to drive time signal generator circuit 2.
Upon input of drive signal c from instruction circuit 1, drive time signal generator circuit 2 generates drive time signal T1 for releasing the dot pins P1 to Pn, which are pulled in when not in use for printing, and drive time signal T2 for maintaining the self-holding current and preventing the dot pins from being pulled in during printing, and sends these drive time signals T1 and T2 to drive circuit 3.
FIG. 3 is a circuit diagram of drive time signal generator circuit 2. Its operation will now be described. When drive signal c is input to inverter 2a capacitor C1 which has been charged is discharged at a rising edge of the drive signal c. Then capacitor C1 is charged by current from drive voltage V.sub.cc via resistor R1 at a falling edge of the drive signal c. The output d of the inverter 2a, which is called a charge/discharge signal, is input into one input terminal (+) of the comparator 2b and one input terminal (+) of another comparator 2c. The +5 V voltage is divided by resistors R2 and R3, and resistors R4 and R5. The voltage across resistor R5 is input as slice level SL1 to the other input terminal (-) of comparator 2b. Likewise, the voltage across resistor R3 is input as slice level SL2 to the other input (-) of comparator 2c. Slice level SL2 is set higher than slice level SL1. Thus, as illustrated in FIG. 2, as long as the level of charge/discharge signal d is less than slice level SL1, the output of comparator 2b, i.e., drive time signal T1 is kept at high level "1", and as long as the level of charge/discharge signal d is less than slice level SL2, the output of comparator 2c, i.e., drive time signal T2 is kept at high level "1".
Upon receipt of the input of print pattern signal b (#b1, #b2, . . . , #bn), and the input of drive time signals T1 and T2 at high level "1", drive circuit 3 (FIG. 1) generates head drive signal e (#e1, #e2, . . . , #en) corresponding to the dot pins, to drive dot print head 4.
FIG. 4 is a circuit diagram of drive circuit 3. As illustrated in FIG. 4, inverter 3a receives drive time signal T1, which is transmitted from drive time signal generator circuit 2. The output of inverter 3a is applied to the base of transistor TRn+1. AND circuits 3b-1, 3b-2, . . . , 3b-n are provided for respective dot pins. Each of the AND circuits 3b-1 to 3b-n receives drive time signal T2 from drive time signal generator circuit 2. AND circuits 3b-1 to 3b-n also reseive print pattern signals #b1 to #bn respectively of the print pattern signal b from instruction circuit 1. AND circuits 3b-1 to 3b-n perform logical product operation, and the outputs from these AND circuits are input, respectively, to the bases of transistors TR1 to TRn, provided for respective dot pins. The emitter of transistor TRn+1 is connected to power supply VMM, and its collector is connected to one end of each of head coils L1 to Ln. The other ends of head coils L1 to Ln are connected, respectively, to the collectors of transistors Tr1 to TRn. Emitters of transistors TR1 to TRn are connected to ground G. Diode Dn+1 is connected across head coils L1 to Ln and transistors TR1 to TRn with its anode grounded. Diodes D1 to Dn are connected between respective collectors of transistors TR1 to TRn and the emitter of transistor TRn+1 with their anodes connected to the collectors of transistors TR1 to TRn.
The following explains the operation of the system as configured above, and in particular the operation of dot pin No. 1 in dot print head 4.
In response to timing signal a, instruction circuit 1 raises print pattern signal #b1 to high level "1" and sends it to drive circuit 3, simultaneously sending drive signal c to drive time signal generator circuit 2 via inverter 2a. When drive signal c rises, capacitor C1 that has been charged is discharged. The level of charge/discharge signal d gradually decreases and when it becomes equal to slice level SL2, comparator 2c sets drive time signal T2 to high level "1", and sends it to drive circuit 3; likewise, when the level of charge/discharge signal d becomes equal to slice level SL1, comparator 2b sets drive time signal T1 to high level "1", and sends it to drive circuit 3. When drive time signal T1 is high transistor TRn+1 of drive circuit 3 is turned on. Further, AND circuit 3b-1 performs logical product operation of drive time signal T2 at high level "1" and character pattern signal #b1 at high level "1". As a result, transistor TR1 is turned on. As a result, head drive signal #e1, or head drive current flows as shown by X1 in FIG. 2 from power supply VMM, through transistor TRn+1, head coil L1, transistor TR1, and to ground G, in that order, This, in turn, generates from coil L1 a magnetic field cancelling the magnetic field, form a permanent magnet not shown, for pulling dot pins. Because of the cancellation of the magnetic field, dot pin No. 1 (P1), being biased by a leaf spring, not shown, is moved forward (toward printing paper 7 on the platen 6) to perform one dot of printing. When drive signal c sent from instruction circuit 1 falls, capacitor C1 in drive time signal generator circuit 2 is charged up. As the level of charge/discharge signal d gradually rises and when it exceeds slice level SL1, drive time signal T1 becomes low level "0". Transistor TRn+1 in drive circuit 3 is thereby turned off. As a result, head drive signal #e1 flows through head coil L1, transistor TR1, diode Dn+1, and head coil L1, in that order. Head drive signal #e1 therefore gradually falls, as shown by X2 in FIG. 2. Further, when the level of charge/discharge signal d in drive time signal generator circuit 2 rises higher than slice level SL2, drive time signal T2 becomes low level "0". As a result, drive signal #e1 flows from ground G, through diode Dn+1, head coil L1, diode D1, and power supply VMM, in that order. Head drive signal #e1 therefore falls quickly as shown by X3 in FIG. 2.
The same operation is performed concurrently and in a similar manner on multiple dot pins that are used for printing.
According to the above scheme, however, the dot pins P1 to Pn that are driven for printing are driven for the same length of time, since print pattern signals b have the same effective period. The drive time is set to the maximum value in order to accommodate the dot pin requiring the greatest length of print time and stroke. Consequently, dot pins that print quickly or those requiring smaller strokes remain in operation by the drive current even after expiration of time required for printing. This results in delayed return. Also, since the drive time is set to the maximum drive time of the dot pins, the power consumption tends to be higher. If the drive period is shortened the problem of missing dots occurs or ribbon 5 can be caught by the pin return of which is delayed.


The present invention relates to processes for the manufacture of one or more ethanolamines and one or more ethyleneamines starting from the reaction of ethylene oxide with ammonia to produce one or more ethanolamines and the conversion of the ethanolamine(s) to ethyleneamine(s). The present invention also relates to separating alkylethyleneamines from ethyleneamines.

Multi-reaction processes for making product mixtures of ethanolamines and ethyleneamines from ethylene oxide and ammonia are known. See, for example, PCT Publication Number WO 2006/114417 and U.S. Pat. No. 4,400,539 (Gibson et al.).
PCT Publication Number WO 2006/114417 discloses a method for producing ethyleneamines, in which ethylene oxide (EO) is continuously reacted with ammonia on an inorganic ion exchanger as a heterogeneous catalyst in anhydrous conditions in a first reaction stage, the obtained reaction product containing monoethanolamine (MEOA), diethanolamine (DEOA), and triethanolamine (TEOA) at a weight ratio MEOA:DEOA:TEOA=80-94:5.9-15:0.1-5, and the reaction product is then continuously reacted with ammonia in the presence of hydrogen and a heterogeneous hydrogenation catalyst in a second reaction stage.
Gibson et al. discloses a continuous process for the manufacture of ethylenediamine from the products of the reaction of ethylene oxide and ammonia, provision of a continuous recycle stream of monoethanolamine to the products of the reaction of ethylene oxide and ammonia, the amination of such products of the reaction of ethylene oxide and ammonia combined with the monoethanolamine recycle in which the feed stream to the amination reaction zone contains at least 70 weight percent monoethanolamine as well as diethanolamine and triethanolamine, the moles of ammonia provided to the amination reaction exceeds the molar concentration of alcoholic hydroxyl groups present in the amination feed, and the feed to the amination reactor contains at least a 5% increase in the concentration of monoethanolamine over the concentration of monoethanolamine in the reaction product stream from the reaction of ethylene oxide and ammonia.
There is an ongoing desire to improve upon such known processes by reducing capital costs, reducing energy costs/improving operating efficiency, improving catalyst selectivity, improving product quality, improving product selectivity, combinations of these, and the like.
For example, it is desirable to manufacture ethanolamines and ethyleneamines from ethylene oxide and ammonia with the minimum amount of unit operations (e.g., ammonia recycle systems, water removal systems, combinations of these, and the like), yet be able to keep impurity levels at a minimum by reducing the production of impurities as by-products and/or being able to remove by-product impurities more effectively.

Methods for making ethanolamine(s) and ethyleneamine(s) from ethylene oxide and ammonia, and related methods


In solder paste of the present invention, a first metal powder, a second metal powder, and a third metal powder are dispersed in a flux or a thermosetting resin. The first metal powder includes a first metal material such as Cu, Ag, Au, or Pd that serves as a base metal. A second metal material such as Sn or In that has a melting point lower than that of the first metal material is coated on the surface of the first metal material. The second metal powder is made of a metal material such as Sn or In that has a melting point lower than that of the first metal material. The third metal powder such as a Cu, Ag, Au or Pd powder has an average particle diameter smaller than that of the first metal material and can form compounds with the second metal material and the second metal powder. Accordingly, the likelihood of unreacted components remaining after a heat treatment can be suppressed, and even when a reflow treatment is repeated a plurality of times, a decrease in the bonding strength of solder bonding can be prevented.

Recently, solder materials that do not contain Pb, such as Sn—Cu eutectic solder and Sn—Ag eutectic solder, have been actively developed so as to replace known Sn—Pb solder as a solder material used for mounting electronic components, in consideration of the environment.
For example, Patent Document 1 discloses solder including Cu balls and Sn balls wherein a compound containing Cu6Sn5 is formed by the Sn balls and some of the Cu balls at a temperature equal to or higher than the melting point of Sn, and the Cu balls are bonded to each other by the compound containing Cu6Sn5.
Patent Document 1 discloses Sn—Cu eutectic solder paste in which a first metal powder 104 prepared by forming a Sn film 103 on the surfaces of Cu balls (powder) 102 by plating and Sn balls (powder) 105 are dispersed in a flux 106, as shown in FIG. 6.
According to Patent Document 1, and as shown in FIG. 7, solder paste 101 is applied on a conductive part of a printed circuit board 107, and a chip-type electronic component 108 such as a monolithic ceramic capacitor is then mounted thereon. When a reflow treatment is then performed at a temperature of 250° C. or higher, the Sn component (derived from the plated films and the Sn powder) is melted. The Cu balls 102 is wetted and dispersed in the molten Sn component, and the Cu balls 102 is uniformly diffused in the flux 106 to form an intermetallic compound 109 composed of Cu6Sn5, as shown in FIG. 8. Accordingly, the printed circuit board 107 and the electronic component 108 are electrically bonded, with solder 110 therebetween.    Patent Document 1: Japanese Patent No. 3558063

This patent is subject to a terminal disclaimer.


According to one embodiment, a semiconductor device includes a semiconductor element, a mounting member including Cu, and a bonding layer provided between the semiconductor element and the mounting member. The bonding layer includes a first region including Ti and Cu, and a second region provided between the first region and the mounting member, and including Sn and Cu. A first position along the first direction is positioned between the semiconductor element and a second position along the first direction. The first position is where the composition ratio of Ti in the first region is 0.1 times a maximum value of the composition ratio of Ti. The second position is where the composition ratio of Sn in the second region is 0.1 times a maximum value of the composition ratio of Sn. A distance between the first position and the second position is not less than 0.1 micrometers.

In a semiconductor device, a semiconductor element is bonded to a mounting member. It is desirable for the thermal resistance of the bond to be low to obtain good heat dissipation by efficiently conducting the heat of the semiconductor element to the mounting member. High productivity is desirable for such a semiconductor device.

Semiconductor device and method for manufacturing the same


A radio link management system for a home or office substantially (i) an ad hoc network of agents wirelessly communicating among themselves, while (iii) clients wirelessly communicate with proximate agents. Control of the network may be centralized as network controller integrated with an agent, or may be distributed upon the network of agents. Some agent or agents, which may include an agent that is also the network controller, typically serves as a gateway device which connects to a worldwide communications network external to the home or office, normally by fiber or by wire.

1. Field of the Invention
The present invention generally concerns wireless communication, including in the home or office.
The present invention particularly concerns power, and bandwidth, management in and for wireless communications systems, most particularly as may be located in the home or office.
The present invention still more particularly concerns power and bandwidth management for wireless communications systems, especially as are used in the home of office, that is adaptive, and tailored to communications conditions.
2. Description of the Prior Art
2.1 Bluetooth and Home RF: Industry Efforts for Wireless Networking
The present invention will be seen to concern power management in and for home and office wireless communications systems. Before specifically considering power management, it is useful to understand just what is the xe2x80x9cstate of the artxe2x80x9d in home and office wireless communications, circa 1999. In this regard, Bluetooth and Home RF are the leading international efforts for wireless networking.
Bluetooth (www.bluetooth.com) is an effort by a consortium of companies to design a universal framework that offers a way to access information based on a diverse set of devices (e.g PDA, mobile PCs, phones, pagers) in a seamless, user-friendly and efficient manner. Bluetooth envisages a functional and connectivity model based on a combination of wireless access technologiesxe2x80x94each matched to different device capabilities and requirements.
Another group of companies has formed the Home RF Working Group or Home RF (www.homerf.org), which has created the Shared Wireless Access Protocol (or SWAP).
The present invention will be seen to be a system and a method that can be implemented by use of the Bluetooth, or the HomeRF, standard and protocol, among other standards and protocols. Review of these wireless communications standards is useful primarily so as to show that the wireless communications links realized by the present invention are neither new nor exotic; circa 2000.
2.2 Bluetooth
xe2x80x9cBluetoothxe2x80x9d is each of a consortium, a standard, and a (prospective) class of products. The present invention will be seen to be none of these: it is a system and a method that can be implemented by use of the Bluetooth standard and protocol, among other standards and protocols. Review of Bluetooth is useful primarily so as to show that the wireless communications links realized by the present invention are readily implemented, circa 2000.
A few years ago, the telecommunications and computing industries recognized that a truly low-cost, low-power radio based cable replacement, or wireless link, was feasible. Such a ubiquitous link would provide the basis for small portable devices to communicate together in an ad-hoc fashion. A study was performed, and a technology code named xe2x80x9cBluetoothxe2x80x9d began to be defined. The goal was to provide effortless service for mobile and business users by means of a small, short range radio-based technology suitably integrated into production line models of a range of different devices.
Five companiesxe2x80x94Ericsson, IBM, Intel, Nokia and Toshibaxe2x80x94teamed up in May, 1998, to address the rising tide of information currently received on mobile computers, cell phones and personal digital assistants. The result was the Bluetooth wireless communications initiative.
As of October, 1998, some 200 companies including 3Com, Compaq, Dell, Hewlett-Packard, Lucent, Motorola, NTT DoCoMo, Philips, Samsung, Siemens and Texas Instruments have joined the Bluetooth Special Interest Group (SIG).
Bluetooth technology is intended to enable users to connect their mobile computers, digital cellular phones, hand-held devices, network access points and other mobile devices via wireless short-range radio links unimpeded by line-of-sight restrictions.
Eliminating the need for proprietary cables to connect devices, Bluetooth technology will increase the ease and breadth of wireless connectivity. Users will be able to automatically receive e-mail on their notebook computers via the digital cellular phones in their pockets, or synchronize their primary PC with their hand-held computer without taking it out of their briefcase.
The overwhelming interest in Bluetooth technology from a wide range of industries demonstrates the growing importance of wireless communication, said Andrew M. Seybold, editor-in-chief, Andrew Seybolds Outlook and keynote speaker at the Bluetooth Developers Conference. Mr. Seybold found the Bluetooth SIG to include the right balance of industry leaders who can make the vision a reality.
The Bluetooth specification version 1.0 was publicly released on Jul. 26, 1999, and product announcements are imminent as of Fall, 1999. Early Bluetooth-enabled products are expected to include mobile computers, hand-held PCs, digital cellular phones and peripherals such as printers, projectors, PC Cards and hands-free head-sets. Network access points will also be available to facilitate access to LANs and WANs.
The core Bluetooth programmed wireless transmitter/receiver is expected to permit a free flow of data without bulky cables. The technology, which ultimately may cost as little as $5, is designed to work anywhere, even on airplanes.
Low power consumptionxe2x80x94drawing only 0.3 mA in standby modexe2x80x94enables maximum performance longevity for battery-powered devices. During data transfer the maximum current drain is 30 mA. However, during pauses, or at lower data rates, the drain will be lower.
2.3 The HomeRF Working Group
xe2x80x9cHomeRFxe2x80x9d is also each of a consortium, a standard, and a (prospective) class of products. As before, the present invention will be seen to be none of these, but only susceptible of implementation under the HomeRF standard. Review of HomeRF is useful primarily so as to again show, as with Bluetooth, that the wireless communications links realized by the present invention are readily implemented, circa 2000.
The HomeRF Working Group (HRFWG) was formed to provide the foundation for a broad range of inter-operable consumer devices by establishing an open industry specification for wireless digital communication. The specification is directed to wireless digital communication between PCs and consumer electronic devices anywhere in and around the home. The HRFWG, which includes the leading companies from the personal computer, consumer electronics, peripherals, communications, software, and semiconductor industries, has developed a specification for wireless communications in the home called the Shared Wireless Access Protocol (SWAP).
To date, the high cost and impracticality of adding new wires have inhibited the widespread adoption of home networking technologies. Wired technologies also do not permit users to roam about with portable devices. In addition, multiple, incompatible communication standards have previously limited acceptance of wireless networks in the home. The HRFWG believes that the open SWAP specification will break through these barriers by (1) enabling inter-operability between many different consumer electronic devices available from a large number of manufacturers, while (2) providing the flexibility and mobility of a wireless solution. This flexibility is important to the success of creating a compelling and complete home network solution.
Since the formation of the HEFWG was announced in March 1998, the total number of member companies has risen to more than 90, and continues to expand quickly. The inclusion of nearly all the leading consumer electronics companies in the working group ensures that consumers will benefit from a wide variety of innovative, inter-operable devices for use in and around the home.
2.3.1 Shared Wireless Access Protocol
The SWAP specification of the HomeRF Working Group (HRFWG) defines a new common interface that supports wireless voice and data networking in the home. Representation from the wide range of member companies, which span diverse industries, ensures that the final specification is complete and robust, and that devices envisioned as part of the home network are inter-operable. The SWAP specification is on target for release at the end of 1998.
Some examples of what users will be able to do with the availability of products that adhere to the SWAP specification include:
setting up a wireless home network to share voice and data between PC""s, peripherals, PC-enhanced cordless phones, and new devices such as portable, remote display pads;
accessing the Internet from anywhere in and around the home from portable display devices;
sharing an ISP connection between PC""s and other new devices;
sharing files/modems/printers in multi-PC homes;
intelligently forwarding incoming telephone calls to multiple cordless handsets, FAX machines and voice mailboxes.
reviewing incoming voice, FAX and e-mail messages from a small PC-enhanced cordless telephone handset;
activating other home electronic systems by simply speaking a command into a PC-enhanced cordless handset; and
enabling multi-player games and/or toys based on PC or Internet resources.
2.4 Issues of Power, and Bandwidth, Utilization Optimization in the Home and Office Wireless Communications Environment
The present invention deals with issues, and problems, regarding the utilization of both (i) power and (ii) bandwidth in the wireless communications environment, particularly in the home and/or office. These issues and problems are reasonably sophisticated, and sometimes subtle.
It is, of course, immediately obvious that wireless-communicating, normally radio-communicating, devices that are battery-powered should attempt to conserve power to (i) maximize the duration(s) of communication connectivity, and (ii) minimize the duration, frequency, inconvenience and expense of any necessary battery recharging and/or replacement. It is less obvious that there is a tradeoff between battery power and communications bandwidth. Less power may be used to realize a given signal-to-noise ratio if more radio communications bandwidth is used, and vice versa.
Each individual radio-communicating device may normally acceptably use relatively more radio bandwidth without unduly interfering with other devicesxe2x80x94which may also desire large communications bandwidthsxe2x80x94if the radius of communication is relatively shorter. But how can a short communication radius invariably be assured? And, if sufficient power is normally provided for only but a short communication distance, how can it be assured that enough power will be available should communications need to transpire over a longer distance? And how can it be assured that multiple broadband communicating devices will never be in conflict?
Worse, power and/or bandwidth communications allocations requirements may change (i) over time and (ii) with the location(s) of communicating devices. A intrinsically low-power device, or just a device running low on power, may simply refuse to communicate at a high data rate, or in a high-power channel communications code. Such a low-power device may need a lot of bandwidth to successfully communicate at all. A wireless communications system must accommodate the requirements of communicating both to, and from, such a low-power device.
However, at another time, and/or in another location, another device, or even the same device, may have abundant power, and may reasonably have a requirement to communicate at a high rate and/or in channel communications mode that is of high overall power and/or a narrow bandwidth (i.e., at a high power per unit bandwidth).
The present invention will be seen to (i) present a communications system framework that is intrinsically superior for the home and office wireless communications environment, and then, this framework being established, (ii) show how wireless communications may be dynamically adapted and optimizedxe2x80x94both in power and bandwidthxe2x80x94to the exigencies of the moment, communicating optimally for conditions.
The present invention contemplates a new system organization, and method, for wirelessly communicating within the home or office, and certain new equipments needed to realize this new method.
Major problems associated with wireless at-home networks include (i) the wide variety of devices and applications which must be supported, (ii) cost, (iii) power constraints, and (iv) bandwidth constraints. The present invention deals with these problems in and by a dual strategy: (i) a superior home and office communications system xe2x80x9cframeworkxe2x80x9d is adopted, and then, this xe2x80x9cframeworkxe2x80x9d being set in place, (ii) wireless communications upon the xe2x80x9cframeworkxe2x80x9d is dynamically adapted and optimized in both power and bandwidth.
In the simplest possible terms, the wireless communication system of (i) superior design in accordance with the present invention is preferably (ii) operated adaptively, realizing superior wireless communication rates and reliability.
1. A Home and Office Wireless Communication System of New Design Uses xe2x80x9cAgentsxe2x80x9d; The xe2x80x9cAgentsxe2x80x9d Make the System Operate in Two Tiers, With Optimization of Communication
The improvement accorded by the present invention to the existing xe2x80x9cframeworkxe2x80x9d of home and office wireless communication systems is this: the present invention adds xe2x80x9cagentsxe2x80x9d. In accordance with the present invention, much of the communications power requirement for local, home or office, wireless communication away from xe2x80x9cclientsxe2x80x9d is moved from these xe2x80x9cclientsxe2x80x9d onto a new class of radio-communicating networked devices which include intermediaries in the overall scheme of wireless communications and are referred herein as xe2x80x9cagents.xe2x80x9d Examples for xe2x80x9cclientsxe2x80x9d include, among others, functional devices such as telephones, computers, televisions, key pad controllers, burglar alarms, household appliances, and hybrids thereof. These abundant, low-cost, agents are essentially non-power-limited radio-frequency transceivers that plug inconspicuously into otherwise unused wall power outlets of the home or business. The agents may physically resemble surge protectors.
The agents are reasonably capable and xe2x80x9cintelligentxe2x80x9d to self-organize into communications networks, as will be discussed. They are typically more capable than are the system clients, which are relegated to wireless communicating only with agents along but a few wireless links.
Although some clients, notably including non-portable species of computers and larger televisions, heavy appliances, and burglar alarms, are permanently connected to the power grid, other battery-powered clients, notably including telephones, portable computers and portable radios and televisions, can immediately benefit from the present invention""s re-partitionment of the xe2x80x9cframeworkxe2x80x9d of wireless communications. This is because the power requirements for these clients are sharply reduced: the clients need normally wirelessly communicate only to a very nearby agent a power-grid-powered wall-plugged radio frequency transceiver that is normally within the same room. Certainly, some clients that are permanently connected to the power grid may also be beneficially combined with agents.
Next, the same re-partitionment simultaneously beneficially conserves local radio frequency bandwidth. A client, especially a battery-powered mobile client, wirelessly communicates only with that agent to which it is electrophysically closest, normally over a distance of but a few meters. Very little radio frequency power need be used and, in accordance with the present invention, is used. The communications of other clients with other agents elsewhere in the same home or business is non-interfering (by action of agent-network-controlled agent-client communication, as will be explained).
The same re-partitionment also has a benevolent, or at worst a neutral, effect on issues of cost and diversity of devices supported. Basically, the abundantly-produced and liberally-sited ubiquitous wall-powered agents (i) eliminate, or at least mitigate, some of the requirements for (a) power, and/or for (b) sophistication in power management, in wirelessly-communicating home and/or office client devices. Meanwhile, the agents (ii) simultaneously lessen constraints, and/or any required sophistication, in the use of RF bandwidth by these client devices. Therefore, and although the agentsxe2x80x94the wall-powered RF transceiver modulesxe2x80x94are reasonably sophisticated (in accordance with existing communications protocols) in self-organizing into a wireless communications network, and are thus estimated to cost some few dollars each, the agents potentially (i) diminish demands on other home/office wireless communications system components, while (ii) adding great value to home/office wireless communications system performance.
The present invention is of good utility and effect just by addition of the agents, without more. However, once the agents are inserted into a home or office wireless communications system, the present invention contemplates still further improvements.
1.2 The Agents are Intelligent, Endowing the Wireless Communications Network Upon Which They are Distributed With xe2x80x9cAdaptive Intelligencexe2x80x9d as Permits Communication Optimization
The agents are not merely radio repeaters. They also implement an expandable, open-ended, dynamic, distributed radio communications management system.
The collective agentsxe2x80x94the distributed radio communications management systemxe2x80x94a) registers clients (either at-home or visiting), b) authenticates visitors, c) maintains a link to external networks (e.g., to the PSTN, or the Internet), d) self-organizes a communications mesh e) implementing the MAC protocol, f) implements the LLC protocol, g) maintains link addresses for all clients and agents, and, most importantly, h) adapts the mesh, and the communications upon the mesh, to the numbers, powers and instantaneous communications requirements of the clients then connected on and by the communications mesh.
Little of this functionality is earthshaking, being that it has, by and large, recently come to exist in cellular and other mesh communications networks. In the past, however, the digital xe2x80x9cintelligencexe2x80x9d associated with communications system management has been reserved for physically large, geographically extensive, communications systems such as might typically serve a town or a city. The present invention has the xe2x80x9caudacityxe2x80x9d to bring the most powerful mesh communications methodsxe2x80x94developed over decades at immense cost but as are now increasingly implemented in application specific integrated circuit chipsxe2x80x94directly into the smallest environment: the home or office. Exactly because this environment is the xe2x80x9cpoorestxe2x80x9d in every wayxe2x80x94in power, in bandwidth, and in the confusingly high diversity of low sophistication communicating equipmentsxe2x80x94it is the very environment that can most benefit from the application of state-of-the-art sophisticated distributed communications control methodology. This is exactly the present invention teaches to do.
1.3 A Two-Tier Wireless Communications Network
The agents and clients of the present invention implement a xe2x80x9ctwo-tierxe2x80x9d wireless communications system. The invention may thus be thought of as a xe2x80x9ctwo-tierxe2x80x9d wireless communications system, and/or to be embodied in a xe2x80x9ctwo-tierxe2x80x9d wireless communications system. The xe2x80x9ctwo tiersxe2x80x9d are tiers of a communications hierarchy: in a first communications tier the agents communicate with other agents; in a second communications tier the local clients of each agent communicate with that agent.
Communications in each of the two tiers may be, and preferably is, separately conducted from communications in the other tierxe2x80x94but need not be so separated and divided. For example, in one embodiment of the xe2x80x9ctwo-tierxe2x80x9d wireless communications system of the present invention communications between agents in one tier is at a different radio frequency than communication between an agent and its associated clients otherwise transpiring in the other tier. In another embodiment of the xe2x80x9ctwo-tierxe2x80x9d wireless communications system of the present invention communications between agents in one tier transpires during a different time slice than does communication between an agent and its associated clients otherwise transpiring in the other tier. In still yet another embodiment of the xe2x80x9ctwo-tierxe2x80x9d wireless communications system of the present invention communications between agents in one tier transpires with and at different code divisions than does communication between an agent and its associated clients in the other tier.
Although the communication in tiers is preferably so separated and divided in any of frequency, time division or code division, the communication need not invariably be so divided. Instead, the unique address of each agent and client can be relied upon.
Consider first the agents. When a group of agents is initially powered on, or a new agent is introduced to an existing group, all the agents will attempt to, and willxe2x80x94in a manner and procedure quite normal for wireless communicationsxe2x80x94form an ad hoc (wireless) communications network. Each agent attempts to communicate with every other. Some communications links are enabled; others fail. The agents serve to create ad hoc what can ultimately be expressed in a conventional connectivity diagram where, by convention, a line is drawn an the diagram between two devices that are (radio) communicating. Where no communication is present, no line is drawn.
The agents thus form of themselves, and without outside intervention or control, a (radio) communications mesh. This mesh, this ad hoc communications network, is the xe2x80x9cbackbonexe2x80x9d of the two-tier wireless (radio) communications network of the present invention. Communication between agents may transpire under the IEEE 802.11 standard, or the Bluetooth standard, or any suitable network radio communications standard.
Consider now the clients. The numerous clients are desirably simpler, and less expensive, than are the agents. The clients use less power than do the agents. Attendant upon a lack of both (i) sophistication, and (ii) power, the preferred clients are typically not capable, as are the agents, of self-organizing into a communications network. Instead, the clients may be and preferably are, by way of example, impressed with a series of fixed addresses at the times when they, are built. Upon being powered on, the client will look to communicate with each of these fixed addresses in turn, and will ultimately end up addressing a local agent. From this point forward the client will communicate only with its associated agent. This communication also may transpire under the IEEE 802.11 standard, or the Bluetooth standard, or any suitable network radio communications standard.
2. Embodiments of the Present Invention
Accordingly, the present invention may be considered to be embodied in each of (i) a local wireless communications system, (ii) a wireless communications system where power and/or bandwidth is allocated efficiently, (iii) a wireless communications system distributed among and between power-grid-powered intelligent xe2x80x9cagentsxe2x80x9d communicatively servicing battery-powered dumb clients, and (iv) a two-tier wireless communications system.
2.1 A Local Wireless Communications System
Therefore, in one of its aspects the present invention may be considered to be embodied in a local wireless communications system. A xe2x80x9clocalxe2x80x9d wireless communications system means a system for, most commonly, a home or a business, or even a farm or a mall or a school or a business park. However, a xe2x80x9clocalxe2x80x9d wireless communications system is not a system for a neighborhood, nor for a community, nor for a city, nor for other, still larger, areas.
The system has number of clients, at least one of which is powered from a portable power source. Each client locally wirelessly communicates by radio. Each client performs an additional function with, and for, a human user other than just radio communication. Indeed, this is the meaning of a xe2x80x9cclientxe2x80x9d, which is something that performs a function beyond just radio communication. Examples of xe2x80x9cclientsxe2x80x9d are radio-communicating telephones, televisions, computers, keypad controllers, burglar alarms, and appliances.
The system further includes a number of communication agents. Each agent is powered from a power grid. The agents first locally wirelessly radio-communicate between themselves in a local wireless radio communications network. The agents second locally wirelessly radio-communicating with the plurality of clients.
An optional communications gateway device, also powered from the power grid, controls local wireless radio communication (i) between the agents upon the network and (ii) an external worldwide communications network (e.g., the Internet).
By this organization the agents are each powered from the power grid while at least one of the clientsxe2x80x94and normally many, most or even all clientsxe2x80x94is powered from a portable power source. Nonetheless that an individual client may be powered by battery power source, it can radio-communicate to at least dome agent. Meanwhile, the several power-grid-powered agents communicate via radio links among themselves in a communications mesh network. Therefore, at the very onset, the system of the present invention suffices to extend battery-powered radio-communication from a battery-powered radio-communicating agent to at least some number of power-grid-powered communication agents.
If the communications system includes the optional communications gateway device, also powered from the power grid, that globally communicates to a worldwide communications network external to the local area of radio communication, then this gateway device may be functionally separate from all the plurality of communications agents, in which case it locally wirelessly radio-communicates with at least one agent. Alternatively, this communications device may be integrated with a communications agent, in which case it is powered from the power grid identically as is the communications agent.
The gateway communications device may be of the order of a modem, globally communicating via a physical communication channel of a wire or a fiber type. The communications device may be of the order of a long range radio or optical transceiver, globally communicating via an atmospheric communication channel of the radio of free-space optical types.
In either case, it is clear that a communications path is extended all the way from the at least one client that may be, and most often is, battery-powered via one or more agents, and via the communications gateway devicexe2x80x94all of which are power-grid-poweredxe2x80x94all the way to a global communications network.
Since only at least one client needs to be powered from a battery power source, not all clients have to be so battery-powered and, indeed, some of the clients may be powered from the power grid. In this casexe2x80x94where at least some clients are powered from the power gridxe2x80x94then at least some of these power-grid-powered clients are physically housed with some ones of the agents. The agents are, of course, all and always powered from the power grid. This is to say no more than that clients and agents may be combined, with some network-radio-communicating power-grid-powered devices being both (i) clients and (ii) agents without in any way diminishing, let alone destroying, the integrity of the present invention. For example, that a power-grid-powered computer work station should be network-radio-communicating (or vice versa that a network-radio-communicating computer work station should be power-grid-powered), in no way detracts from the application, and benefit, of the present invention that, to continue the example, a battery powered telephone should be radio-communicating to, and through, a power-grid-powered network-radio-communicating agent.
In certain, preferred, embodiments of the system the radio-communicating between clients upon the network is multi-hop. This multi-hop radio-communicating between clients upon the network is preferably may be in accordance with any of several wireless communications protocols.
To again emphasize the utility, and the trade-offs, in such a communications system, consider that the radio-communicating between clients upon the network preferably transpires in a communications protocol that consumes a relatively higher power while radio-communicating between the clients and the agents transpires in a communications protocol that consumes a relatively less power. Clearly the power consumed radio-communicating between at least that client which is powered from a portable power source, and an agent, which is invariably powered from a power grid, is less than power consumed radio-communicating between the of agents. Clearly power is conserved to the client, which is beneficial if the client is battery-powered.
Meanwhile, consider that the radio-communicating between the clients upon the network preferably transpires in a communications protocol that consumes a relatively more bandwidth (and relatively less time) while radio-communicating between the plurality of clients and the plurality of agents transpires in a communications protocol that consumes relatively less bandwidth (and relatively more time). Clearly the spectrum (and the time) of radio communication is partitioned. This is desirable when, as is the case with the present invention, available spectrum is made available to those devices with the power to use it (i.e., power grid power), and withheld from those devices without sufficient power (i.e., with only battery power) to fully avail themselves of it.
2.2 A Wireless Communications System Allocating Large Bandwidth Where There is Power to Use Bandwidth (Equivalently, Conserving Bandwidth Where There is Insufficient Power for Its Effective Use), or, Alternatively, Organized for Providing Power Where Large Bandwidth May Effectively Be Used (Equivalently, Accommodating Lower Power Where Bandwidth May Not Efficiently be Used)
By this point in this specification it should be beginning to be understood that the present invention is not merely yet another assemblage of parts, and yet another partitionment of a radio system, for moving a message by message by radio from point xe2x80x9cAxe2x80x9d to point xe2x80x9cBxe2x80x9d, but is instead concerned with optimally so doing. Optimization in accordance with the present invention is in consideration of each of (1) power constraints, (2) bandwidth constraints, (3) the wide variety of radio-communicating devices and applications which must be supported, and (4) cost.
In another of its aspects the present invention may be considered to be embodied in a radio link management system for a home or office. The system has (i) a network of agents wirelessly communicating among themselves, and (ii) clients wirelessly communicating with proximate agents. An (i) agent may also be a (ii) client, and vice versaxe2x80x94although agents and clients are mostly separate. Control of the network may be (i) centralized, as on a network controller that is integrated with an agent, or may be (ii) distributed upon the network of agents. Some agent or agents, which may include an agent that is integrated with a network controller, typically connects to one or more communications servers external to the home or office, normally by fiber or by wire. This connection is most commonly to a worldwide digital communications network, also known as the Internet.
Each agent is most commonly a small radio transceiver plus logic and power supply that mounts on a wall and plugs directly into an AC power socket. Agents wirelessly communicate among themselves and with any agent that integrates a controller (if network control is centralized, which it most commonly is not) in a bandwidth-efficient mode since prime power is not an issue. Each clientxe2x80x94which is most commonly a battery-powered user devicexe2x80x94wirelessly communicates, normally by radio, with one or more agents, and normally with but one agent at one time.
Consistent with overall demand for the radio resource, the radio management system chooses the parameters for this communication in a manner which is (a) client-dependent, and which (b) uses the least power from the battery-powered clients. The agents establish an ad-hoc network among themselves, with routing among and between the agents being xe2x80x9cminimum hopxe2x80x9d to conserve bandwidth. Accordingly both power and bandwidth are conserved, each as and where required and desired.
The present invention addresses these issues of allocation, and optimizes radio communication, by creating the aforesaid radio link management system consisting of (i) agents plus (ii) clients. In this radio link management system (ii) clients wirelessly communicate through, and only through, the (i) agents. There is no client-to-client communication.
Each (ii) agent is a non-power-limited radio transceiver which attaches to power other than a battery. Most often an agent consists of a small radio transceiver plus logic and power supply that mounts on a wall and plugs directly into an AC power socket. Agents wirelessly communicate among themselves and with any controller (which may be centralized or distributed) always in a bandwidth-efficient mode (since power is not an issue).
The (ii) clients are radio-communicating devices that are power limited, and that are most commonly powered by batteries. Each (ii) client wirelessly communicates with an (i) agent.
Consistent with overall demand for the radio resource, the radio management system chooses the parameters for this communication in a manner which is (a) client-dependent, (b) using the least power from the client (which typically operates from a battery). For example, if radio communication demand is light, then a very powerful channel code might be used when the client transmits. Also, the information and channel rates may be different for different clients. When sending to a particular client, the radio management system uses a format which is compatible with the capabilities of that client.
When the agents establish an ad-hoc network among themselves, in which network communications paths may be, and most often are, multi-hop, then communication paths are xe2x80x9cminimum hopxe2x80x9d to conserve bandwidth. A client may send to an agent different than the one from which it receives: a client sends to the xe2x80x9clowest power requiredxe2x80x9d agent while it listens to the xe2x80x9clowest bandwidth consumedxe2x80x9d agent.
Accordingly, the radio spectrum resource may be viewed as being time-shared among agents and clients, although, in general, the radio resource manager/controller is free to partition time and spectrum in any way consistent with the capabilities of the devices, the demand, and the desire to variously conserve both battery power and radio bandwidth. This is an important concept: because the network is xe2x80x9cad hocxe2x80x9d; it configures in a manner best calculated to conserve bandwidth where, by operation of the present invention, power is innately conserved. If new clients and/or agents are added, the network will automatically re-configure. The network ends up being dynamic, and adaptive, to conserve both battery power and radio bandwidth. For example, suppose some battery-powered client constantly early discharges its batteries in a manner disadvantageous to its desired use. Under this condition, adding an agent plugged to a wall plug in close proximity to the client may serve to significantly help the client""s energy budget, and to usefully prolong the duration of the client""s operation before battery discharge occurs.
2.3 An Adaptive Distributed Wireless Communications System Based on Power-Grid-Powered Intelligent xe2x80x9cAgentsxe2x80x9d Communicatively Servicing Battery-Powered Dumb Clients
In yet another of its aspects the present invention may be considered to be embodied in a distributed radio link, or radio communications, management system.
Such a wireless communications management system serves to communicatively interconnect a plurality of clientsxe2x80x94at least one of which is powered from a portable power source and at least one of which both locally wirelessly communicates by radio and performs some additional function with and for a human user other than just radio communication. The wireless communications management system is implemented as a number of communication agents, each powered from a power grid within a home or business, that collectively form a communications mesh.
Each agent first locally wirelessly radio-communicates with other agents in a local wireless radio communications network, second locally wirelessly radio-communicating with local clients.
The agents collectively (1) register clients to the communications mesh, (2) maintain a link to external networks, and (3) self-organizing the communications mesh.
The collective agents preferably further (4) adapt wireless communications upon the mesh to any of the numbers, powers and instantaneous communications requirements of the clients then connected on and by the communications mesh.
Still further, the collective agents (5) authenticate visiting clients to the communications mesh. When the collective agents (2) maintain the link to the external networks, the preferably so maintain the link to a worldwide communications network, namely, the Internet.
Still further, the collective agents (3) self-organize the communications mesh, they implement the MAC protocol, and also the LLC protocol.
The collective agents preferably further (6) maintain link addresses for all clients and agents.
2.4 A Two-Tier Wireless Communications System
In still yet another of its aspects the present invention may be considered to be embodied in a two-tier wireless communications system.
The system has a number of communication agents that first locally wirelessly radio-communicating between themselves (to such extent as wireless connectivity in a local wireless radio communications network permits). This first locally wirelessly radio-communicating is in a first communications tier separate from any other communications tier. Each agent further second wirelessly radio-communicates with one or more uniquely associated clients (again to such extent as wireless connectivity in a local wireless radio communications network permits). This second wirelessly radio-communicating is in a second communications tier separate from the first and from any other communications tier.
Meanwhile, a number of clients each locally wirelessly radio-communicate to one or more associated agents, only; no communication transpiring to any un-associated ones of the plurality of agents. This local wirelessly radio-communicating is in the second communications tier.
By this partitionment the communication agents are self-organizing to produce a communications mesh while each of the plurality of clients is capable only of identifying, and communicating to, one or more agents. The clients become communicative from one to another only by communication links proceeding through one or more of the plurality of agents.
The first locally wirelessly radio-communicating between plurality of agents at the first communications tier may transpire, for example, at a first radio frequency while the second locally wirelessly radio-communicating between plurality of agents and associated ones of the plurality of clients at the second communications tier transpires at a second radio frequency.
The first locally wirelessly radio-communicating between plurality of agents at the first communications tier may instead transpire at a first time interval, while the second locally wirelessly radio-communicating between plurality of agents and associated ones of the plurality of clients at the second communications tier transpires at a second time interval.
The first locally wirelessly radio-communicating between plurality of agents at the first communications tier may even transpire at a first code division while the second locally wirelessly radio-communicating between plurality of agents and associated ones of the plurality of clients at the second communications tier transpires at a second code division.

Power-  and bandwidth-adaptive in-home wireless communications system with power-grid-powered agents and battery-powered clients

Abstract: Each agent is most commonly a small radio transceiver plus logic and power supply that mounts upon a wall and plugs directly into an AC power socket. Agents wirelessly communicate among themselves and with the controllerxe2x80x94which may be centralized or distributedxe2x80x94in a bandwidth-efficient mode since prime power is not an issue. Each client, which is most commonly a battery-powered user device, wirelessly radio communicates with one or more proximately-located agents. Consistent with overall demand for the radio resource, parameters for radio communication are allocated ad hoc in a manner which is (a) client-dependent, and which (b) uses the least power from the battery-powered client. The agents establish an ad-hoc network among themselves, with routing among and between the agents being both multi-hop and xe2x80x9cminimum hopxe2x80x9d to conserve bandwidth. Accordingly both power and bandwidth are conserved, each as and where required and desired.

The Regents of the University of California


An apparatus includes a first conveyance unit configured to convey a sheet, a first guide located downstream of the first conveyance unit in a conveyance direction and configured to guide a first side end of the conveyed sheet, a skew unit configured to convey the sheet in an oblique direction to come closer to the first guide, a second guide configured to contact a second side end opposite the first side end to guide the second side end, a second conveyance unit located downstream of the first guide in the conveyance direction, and a control unit configured to perform control so that, after conveying the sheet by the skew unit with the first guide contacting the first side end while the second guide is separated from the second side end, the second guide moves to a position close to the second side end.

1. Field of the Invention
The present invention relates to a sheet conveyance apparatus and a recording apparatus that records an image on a sheet.
2. Description of the Related Art
In an image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2005-156974, misregistration and a misaligned posture of the tip of a long sheet are corrected by causing the long sheet to move along a bump guide in parallel along a conveyance direction by a skew roller pair whose rotation surface is tilted toward the bump guide. Twist tension generated in the long sheet is reduced by generating a loop in a loop conveyance unit provided upstream of the guide immediately before the long sheet being caused to move along the bump guide so that skew correction processing with a reduced load can be performed.
Then, image formation with less skew is realized by sandwiching the sheet between a line feed roller pair on the downstream side and restarting conveyance after the skew roller pair being detached.
However, in a configuration, such as that discussed in Japanese Patent Application Laid-Open No. 2005-156974, in which the skew roller pair is detached after the skew at the tip of a long sheet is corrected to allow the long sheet to be conveyed, an issue actually arises of deteriorating conveyance precision with the sheet skewed during conveyance. Reasons for the issue include a factor that because the skew roller pair is detached, torsional tension of the long sheet directly affects the line feed roller pair to deteriorate conveyance balance, resulting in the skew.
If the long sheet is made to be conveyed along the bump guide by the skew rollers, there is an issue that satisfactory image quality cannot be obtained due to an occurrence of surface defects of the sheet because the sheet is conveyed in a state in which the surface thereof is slidingly rubbed by the skew rollers.
Japanese Patent Application Laid-Open No. 2007-225947 discusses a printing apparatus in which a pair of regulatory guides on the left and right sides is provided on a paper path route of roll paper to prevent meandering. Meandering of the roll paper can be prevented by moving the left and right guides to pushed-in positions narrower than the width of the roll paper to correct the posture of the roll paper and then, moving the roll paper width guide position.
In an apparatus discussed in Japanese Patent Application Laid-Open No. 2007-225947, a conveyance roller is provided upstream and downstream of a paper width guide to sandwich and convey roll paper. When meandering is corrected, pressure contact of the conveyance rollers is released and an operation of pushing in roll paper edges further narrower than the paper width by a guide unit is performed. Also, the position of the guide unit is moved according to the width dimension of the roll paper input into the apparatus in advance.
However, to respond to user needs more wide-ranging than in the past, issues cited below manifest themselves when an attempt is made to obtain better printing results by conveying various media with higher precision than in the past:    (1) If meandering occurs during printing and pressure contact of a conveyance roller is released to correct the meandering by a guide unit, conveyance precision of roll paper deteriorates. If a pressure contact force of the conveyance roller is weakened to correct the meandering without releasing pressure contact, conveyance precision of roll paper also deteriorates. Thus, it is difficult to ensure both excellent conveyance precision and meandering correction performance during printing at the same time.    (2) If an operation to push in the guide unit further narrower than the paper width is performed, buckling may occur depending on rigidity of the roll paper to be used so that damage due to the buckling remains in the roll paper.    (3) While the guide unit is aligned based on the roll paper width size input in advance, a gap may arise between the guide unit and roll paper edges due to an error between the actual roll paper width and the input value, precision of parts of the guide unit, positioning precision or the like, thus increasing the possibility of an occurrence of meandering. Conversely, if the guide position swings in a direction in which the roll paper is pushed in, a phenomenon similar to (2) may occur.

Sheet conveyance apparatus and recording apparatus


Overhead associated with verifying function return addresses to protect against security exploits is reduced by taking advantage of branch prediction mechanisms for predicting return addresses. More specifically, returning from a function includes popping a return address from a data stack. Well-known security exploits overwrite the return address on the data stack to hijack control flow. In some processors, a separate data structure referred to as a control stack is used to verify the data stack. When a return instruction is executed, the processor issues an exception if the return addresses on the control stack and the data stack are not identical. This overhead can be avoided by taking advantage of the return address stack, which is a data structure used by the branch predictor to predict return addresses. In most situations, if this prediction is correct, the above check does not need to occur, thus reducing the associated overhead.

The software execution model for calling and returning from a function dictates that upon calling a function, the return address for that function is pushed onto the data stack and upon returning from that function, the return address is popped from the data stack and control flows to that return address. Some security exploits can take advantage of this use of the stack by overwriting the stack entry for a return address with a malicious return address that alters control flow to a location as desired by the attacker. Improvements to techniques for preventing this type of security exploit are constantly being made.

Using return address predictor to speed up control stack return address verification


A support assembly for supporting a high voltage electrical conductor suspended from a lattice-type tower during maintenance and repair includes a pair of elongate support arms, each of the support arms having an aperture extending therethrough intermediate its ends, the aperture opening in a direction transverse to the length of the support arms, and an elongate conductor support bar slidably received in the apertures of the support arms and extending between the support arms to define with the support arms a generally H-shaped support assembly, the support arms being slidable on the support bar for adjusting the distance between the arms and being movable on the support bar between a first position wherein the arms are parallel to each other and a second position wherein the arms are arranged at an angle to each other.

High voltage power transmission lines carrying voltages in the hundreds of kilowatt range have been constructed to extend from spaced towers or poles in terrain which is often practically inaccessible to land vehicles. In recent years, a number of methods and devices have been developed to facilitate the repair and maintenance of high voltage power transmission lines which are accessed by helicopter.
Lattice-type towers are employed for supporting multiple high voltage electrical conductors. The conductors are typically supported under the arms or bridges of such towers using a pair of suspension insulators per conductor. Periodically, it is necessary to replace the insulators because they are visibly damaged or as part of a general maintenance plan. Typically, insulators are attached via pins to the towers and via pins to a yoke plate which supports the conductor. These pins must be manually removed by linemen placed on the tower via helicopter in order to replace the insulators. Damaged or worn insulators are removed from the tower via helicopter and replacement insulators are delivered to the tower via helicopter. It will be appreciated that high voltage electrical conductors are extremely heavy and their great weight hanging from the end of an insulator makes it impossible to unpin and remove the insulator without first creating slack in the insulator. To accomplish this the conductor must be supported in some fashion during insulator removal and replacement. In the past, lineman have improvised temporary rigging to support the conductors. For example, multiple chain hoists have been used which are supported via multiple nylon slings at multiple spaced locations along tower girders. Such improvisation requires large amounts of equipment, is time consuming and fails to adequately distribute the weight of a supported conductor over a large area of the tower structure.
Accordingly, there exists a need for a device which may be safely emplaced on a tower via helicopter, which is light enough to be handled by a lineman on a tower, which is strong enough to support a heavy electrical conductor, which will be stable on a structure such as a lattice-type tower and which will distribute the weight of a supported conductor over the tower structure.


One embodiment provides an analog front-end circuit. When a chopping signal has a first logical value, a non-inverting instrumentation preamplifier subtracts a second input voltage from a first input voltage and generates a first output voltage by amplifying a subtraction voltage while outputting the second input voltage as a second output voltage. When the chopping signal has a second logical value, the non-inverting instrumentation preamplifier subtracts the first input voltage from the second input voltage and generates the first output voltage by amplifying and then inverting the polarity of a subtraction voltage while outputting the second input voltage as the second output voltage.

In analog front-end circuits, a very small analog signal obtained by detecting a temperature, for example, is amplified and AD-converted into data. In this operation, an offset component, a temperature drift, low-frequency noise, etc. (hereinafter referred to as "an offset component etc.") occurring in an instrumentation preamplifier having a high amplification factor and an AD converter have great influences on the performance of the entire circuit.
In view of the above, for example, an analog front-end circuit 20A shown in FIG. 3 is employed which is equipped with a configuration for reducing such offset component etc. (refer to Chopping on the AD7190, AD7192, AD7193, AD7194, and AD7195," Mary McCarthy, AN-1131, APPLICATION NOTE, page 1 of 4, ANALOG DEVICES). The analog front-end circuit 20A is equipped with switches SW11 and SW12 each of which switches between input voltages VINP and VINN that are input from a sensor 1, a differential instrumentation preamplifier 21A which performs differential amplification on the difference between the voltages VINP and VINN that are input via the switches SW11 and SW12, an AD converter 22 for converting the difference between differential output signals VOUTP and VOUTN of the differential instrumentation preamplifier 21A into a digital signal, a switch circuit 23 which passes the output data of the AD converter 22 as it is or after inverting its polarity, and a data calculator 24 for calculating average data of two data that are output from the switch circuit 23 successively.
The differential instrumentation preamplifier 21A is composed of operational amplifiers OP11 and OP12 and gain-setting resistors R11, R12, and R13 (R12=R13), and outputs the voltages VOUTP and VOUTN. The switch circuit 23 is composed of a switch SW13 and a data inverter 23a.
A chopping signal CHOP is a signal that "0" and "1" occur repeatedly and alternately at a prescribed cycle. Each of the switches SW11, SW12, and SW13 selects the input terminals "0" and "1" when the chopping signal CHOP is "0" and "1," respectively.
In FIG. 3, symbols Vos11, Vos12, and Vos13 denote an offset component etc. occurring on the non-inverting input side of the operational amplifier OP11, an offset component etc. occurring on the non-inverting input side of the operational amplifier OP12, and an offset component etc. occurring on the data input side of the AD converter 22, respectively.
In the analog front-end circuit 20A, an output voltage VOCHOP=0 of the switch circuit 23 when the chopping signal CHOP is "0" is given by
                              VO                      CHOP            =            0                          =                                            (                              VINP                -                VINN                            )                        ×                          (                              1                +                                  2                  ×                                                            R                                                                                12                                                              R                                                                                11                                                                                )                                +                                    (                                                Vos                                                                                11                                -                                  Vos                                                                                12                                            )                        ×                          (                              1                +                                  2                  ×                                                            R                                                                                12                                                              R                                                                                11                                                                                )                                +                      Vos                                                                          13.                                              (        1        )
On the other hand, an output voltage VOCHOP=1 of the switch circuit 23 when the chopping signal CHOP is "1" is given by
                              VO                      CHOP            =            1                          =                                            {                                                                    -                                          (                                              VINP                        -                        VINN                                            )                                                        ×                                      (                                          1                      +                                              2                        ×                                                                              R                                                                                12                                                                                R                                                                                11                                                                                )                                                  +                                                      (                                                                  Vos                                                                                11                                            -                                              Vos                                                                                12                                                              )                                    ×                                      (                                          1                      +                                              2                        ×                                                                              R                                                                                12                                                                                R                                                                                11                                                                                )                                                  +                                  Vos                                                                                13                                            }                        ×                          (                              -                1                            )                                =                                                    (                                  VINP                  -                  VINN                                )                            ×                              (                                  1                  +                                      2                    ×                                                                  R                                                                                12                                                                    R                                                                                11                                                                                )                                      -                                          (                                                      Vos                                                                                11                                    -                                      Vos                                                                                12                                                  )                            ×                              (                                  1                  +                                      2                    ×                                                                  R                                                                                12                                                                    R                                                                                11                                                                                )                                      -                          Vos                                                                                13.                                                          (        2        )
Thus, an output OUT of the data calculator 24, that is, the average of two successive output voltages VOCHOP=0 and VOCHOP=1 of the switch circuit 23, is given by
                    OUT        =                                                            VO                                  CHOP                  =                  0                                            +                              VO                                  CHOP                  =                  1                                                      2                    =                                    (                              VINP                -                VINN                            )                        ×                                          (                                  1                  +                                      2                    ×                                                                  R                                                                                12                                                                    R                                                                                11                                                                                )                            .                                                          (        3        )            In Equation (3), the offset components etc. Vos11, Vos12, and Vos13 are eliminated.
However, in the analog front-end circuit 20A described above with reference to FIG. 3 which employs the differential instrumentation preamplifier 21A, output voltages VOUTP and VOUTN of the differential instrumentation preamplifier 21A vary necessarily in opposite directions (differentially). Thus, where the bias points for input signals VINP and VINN are set at low potentials that are close to GND, the output voltages VOUTP and VOUTN are saturated immediately.
FIG. 5C shows example input voltages VINP and VINN and output voltages VOUTP and VOUTN of the differential instrumentation preamplifier 21A of the analog front-end circuit 20A shown in FIG. 3 in which the input voltages VINP and VINN are 2 V and 1 V, respectively. When the chopping signal CHOP is "0," the input voltages VINP and VINN pass the switches SW11 and SW12 as they are, respectively, and hence the output voltages VOUTP and VOUTN and the amplification factor GAIN are given by
                    VOUTP        =                  VINP          +                                                    R                                                                                12                                            R                                                                                11                                      ×                          (                              VINP                -                VINN                            )                                                          (        4        )                                VOUTN        =                  VINN          +                                                    R                                                                                12                                            R                                                                                11                                      ×                          (                              VINN                -                VINP                            )                                                          (        5        )                                GAIN        =                                            VOUTP              -              VOUTN                                      VINP              -              VINN                                =                      1            +                          2              ×                                                R                                                                                12                                                  R                                                                                11                                                                                (        6        )
Where the amplification factor GAIN is 10, R12/R11 is calculated to be 4.5 from Equation (6). Thus, the output voltages VOUTP and VOUTN are calculated asVOUTP=2+4.5×1=6.5(V)VOUTN=1+4.5×(−1)=−3.5(V).
On the other hand, when the chopping signal CHOP is "1," the input voltages VINP and VINN are inverted by the switches SW11 and SW12 and hence the output voltages VOUTP and VOUTN are given by
                    VOUTP        =                  VINN          +                                                    R                                                                                12                                            R                                                                                11                                      ×                          (                              VINN                -                VINP                            )                                                          (        7        )                                VOUTN        =                  VINP          +                                                    R                                                                                12                                            R                                                                                11                                      ×                                          (                                  VINP                  -                  VINN                                )                            .                                                          (        8        )
Thus,VOUTP=1+4.5×(−1)=−3.5(V)VOUTN=2+4.5×1=6.5(V).
As described above, in the analog front-end circuit 20A shown in FIG. 3, theoretically, the output voltages VOUTP and VOUTN can become negative. As a result, where a single power source is employed for the operational amplifiers OP11 and OP12, the negative side is saturated to 0 V. Thus, to handle a single-ended signal in which only a signal VINP that is output from the sensor 1 varies on the positive side and a voltage VINN that is output from the sensor 1 is fixed, it is necessary to set high bias points for the voltages VINP and VINN in advance, which results in a problem that the signal range of the output voltage VOUTP is narrowed.
One measure for widening the signal range is an analog front-end circuit 20B shown in FIG. 4 which employs a non-inverting instrumentation preamplifier 21B which uses a single operational amplifier OP11. FIG. 5D shows example input voltages VINP and VINN and output voltages VOUTP and VOUTN of the differential instrumentation preamplifier 21B of the analog front-end circuit 20B shown in FIG. 4.
When the chopping signal CHOP is "0".
                    VOUTP        =                  VINP          +                                                    R                                                                                12                                            R                                                                                11                                      ×                          (                              VINP                -                VINN                            )                                                          (        9        )                                VOUTN        =        VINN                            (        10        )                                GAIN        =                                            VOUTP              -              VOUTN                                      VINP              -              VINN                                =                      1            +                                          R                                                                                12                                            R                                                                                11                                                                        (        11        )
Where the amplification factor GAIN is 10, R12/R11 is calculated to be 9 from Equation (11). Thus, the output voltages VOUTP and VOUTN are calculated asVOUTP=2+9×1=11(V)VOUTN=1(V).
On the other hand, when the chopping signal CHOP is "1." the output voltages VOUTP and VOUTN are given by
                    VOUTP        =                  VINN          +                                                    R                                                                                12                                            R                                                                                11                                      ×                          (                              VINN                -                VINP                            )                                                          (        12        )                                VOUTN        =                  VINP          .                                    (        13        )
Thus,VOUTP=1+9×(−1)=−8(V)VOUTN=2(V).
In this case, when the chopping signal CHOP is "0," neither of the output voltages VOUTP and VOUTN is saturated and hence a wide signal range can be obtained. However, when the chopping signal CHOP is "1," the output voltage VOUTP becomes negative, which raises the same problem as in the analog front-end circuit 20A shown in FIG. 3.
One object of the invention is to solve the above problems and thereby provide an analog front-end circuit capable of eliminating offset components etc. by a chopper operation and, in addition, preventing saturation of output voltages of an instrumentation preamplifier in a case of handling a single-ended signal having a wide signal range.

Analog front-end circuit including instrumentation preamplifier and A/D converter


Provided herein are systems and methods for extracting lipids and/or producing biofuel from algae in marine and freshwater environments, wherein algae and bivalves are co-cultured in a system of enclosures comprising water that comprises recycled nutrients that are essential for algal growth. The system also include enclosures for culturing fishes which are used to harvest the algae.

The United States presently consumes about 42 billion gallons per year of diesel for transportation. In 2007, a nascent biodiesel industry produced 250 million gallons of a bio-derived diesel substitute produced from mostly soybean oil in the U.S. Biodiesel are fatty acid methyl esters (FAME) made typically by the base-catalyzed transesterification of triglycerides, such as vegetable oil and animal fats. Although similar to petroleum diesel in many physicochemical properties, biodiesel is chemically different and can be used alone (B100) or may be blended with petrodiesel at various concentrations in most modern diesel engines. However, a practical and affordable feedstock for use in biodiesel has yet to be developed that would allow significant displacement of petrodiesel. For example, the price of soybean oil has risen significantly in response to the added demand from the biodiesel industry, thus limiting the growth of the biodiesel industry to less than 1% of the diesel demand.
It has been proposed to use algae as a feedstock for producing biofuel, such as biodiesel. Some algae strains can produce up to 50% of their dried body weight in triglyceride oils. Algae do not need arable land, and can be grown with impaired water, neither of which competes with terrestrial food crops. Moreover, the oil production per acre can be nearly 40 times that of a terrestrial crop, such as soybeans. Although the development of algae presents a feasible option for biofuel production, there is a need to reduce the cost of producing the biofuel from algae. The fall in oil price in late 2008 places an even greater pressure on the fledgling biofuel industry to develop inexpensive and efficient processes. Provided herein is a cost-efficient approach for growing algae in a large scale for production of biofuel.

Systems and methods for culturing algae with bivalves


Described herein is an apparatus and method for providing an inerting gas during the application of soldering to a work piece. In one aspect, there is provided an enclosure for providing an inerting gas into an atmosphere above a solder reservoir during soldering of a work piece comprising: a tube in fluid communication with an inerting gas source wherein the tube comprises one or more openings for the flow of the inerting gas therethrough, a base wherein the tube resides in therein and comprises an interior volume, a neck comprising an opening and an interior volume in fluid communication with the interior volume of the base, and a cap proximal to the opening wherein the inerting gas source travels through the tube into the interior volume and into the atmosphere through the opening defined by the neck and cap.

Described herein are an apparatus and a method for providing an inerting gas during soldering. More specifically, described herein are an apparatus and a method for providing an inerting gas during wave soldering using nitrogen and/or other inerting gas.
Work pieces such as printed wiring boards or circuit boards have increasingly smaller wettable surfaces that need to be solder coated and joined. Typical operations for wave soldering involve a soldering bath through which the printed circuit boards or work pieces to be soldered are transported. A conventional automatic wave soldering apparatus includes a flux application, a preheater, and a solder station that is arranged to process printed circuit boards. The printed circuit boards are transported along a moving track or conveyor with their side edges supported by gripping fingers. Flux may be applied by contacting the board with either a foam or spray of flux. The circuit board is then passed through a pre-heating area in order for the flux to reduce the oxides on the metal surfaces to be soldered. The circuit board is then contacted with single or multiple waves of molten solder in an air or inerting gas atmosphere.
The inerting gas atmosphere typically is nitrogen (N2) and/or other inerting gases and is oftentimes called N2 inerting. Soldering within an inert gas and/or nitrogen atmosphere minimizes the formation of dross or oxides on the surface of the solder. The presence of dross and/or an oxide layer is known to cause skips, bridges, or other defects in solder joints. Proximal to the solder waves—which are produced by the wave soldering apparatus during operation—are porous pipes or tubes which run parallel to the solder wave and are used to transport the inerting gas and/or N2 gas to provide a relatively low oxygen atmosphere, particularly underneath the work piece to be soldered.
For lead-free wave soldering, the value of an inerting gas atmosphere comprising N2 is further increased due to the following reasons. The process temperature using common lead-free solders is significantly higher than that of conventional tin-lead solder due to the increased melting points of commonly used lead-free solders. This increase in process temperature promotes dross formation. Furthermore, the cost of lead-free solder is normally much higher than that of conventional tin-lead solder, and the economy loss associated with solder waste by dross formation is more significant than that of lead-free wave soldering. In addition, the wetting performance of lead-free solder is intrinsically poor compared with that of conventional tin-lead solder. Therefore, the quality of the formed solder joints is more sensitive to the state of oxidation on a lead-free solder surface.
It is well known that inerting in wave soldering can significantly reduce dross formation on the molten solder surface. Reducing dross formation not only saves solder material and lessens maintenance requirements, but also improves solder wetting and ensures the quality of the formed solder joints. To apply an inerting atmosphere in an existing wave soldering machine, one common approach is to insert a cage-like protective housing with diffusers mounted inside into the molten solder reservoir. An inerting gas blanket across the solder reservoir can thus be formed, reducing the tendency of solder oxidation.
The diffusers are commonly made of porous tubes that introduce an inerting gas such as N2 and/or other inerting gases into the soldering station. The porous tubes, however, become easily clogged by solder splashing or flux vapor condensation during the wave soldering process. Once the diffuser tube is clogged, the efficiency of inerting will be largely reduced. Present methods of cleaning the diffuser tubes such as, for example, using ultrasonic baths filled with cleaning solutions, are extremely difficult and time consuming. The cleaning of these tubes must be performed on a regular basis and can cause physical damage to the tubes. To avoid these issues, the diffuser tubes are typically replaced once they become clogged rather than cleaned. This increases the overall cost to the end-user.
Accordingly, in order to promote the application of inerting by N2 and/or other inerting gases in wave soldering, it is desirable that the apparatus, method, or both fulfill at least one or more of the following objectives. First, it is desirable that the inerting apparatus and method reduces N2 or other inerting gas consumption to a level such as, but not limited to, 12 cubic meters per hour (m3/hr) or less for inerting a production-scale solder reservoir to meet the cost benefits of applying the technology. Second, it is desirable that the inerting apparatus and method reduces the concentration of O2 above the molten solder surface to a level such as, but not limited to, 2500 parts per million (ppm) or less, or 2000 ppm or less, which corresponds to the cases in which no circuit board is loaded above the solder pot. Third, it is desirable that the inerting apparatus and method uses an apparatus that is simple to install and maintain to minimize retrofitting cost. Moreover, it is desirable that the apparatus or method reduces or eliminates the clogging of the porous diffuser tube to ensure a stable and long lasting inerting performance.

Method for providing an inerting gas during soldering


The present invention offers an electronic money system and electronic money terminal that allow the user who uses an installment payment plan to decide the installment amount each time he/she pays it.

Conventionally, when a user uses a cash card or credit card issued by a bank, credit company, or the like at a store where a card terminal that accepts the card has been installed, the clerk at the store makes the card terminal read the card number stored on the magnetic stripe of the card and enters the transaction amount.
At this time, the card terminal connects to a communication line and sends information such as the card number and transaction amount to the management computer at the bank or credit company. The management computer at the bank or credit company manages such information as whether the card has been expired, whether the credit limit has been reached, and whether the card has been reported lost, and determines whether the card can be used, based on the card-number and payment-amount information received from the card terminal via the communication line. If it is determined that the card can be used, the management computer at the bank or credit company returns usage permission information to the sender card terminal while performing a procedure for debiting the transaction amount from the specified account of the card.
There is a problem with a system that employs such cash cards or credit cards: each time the user uses his/her card, the card terminal must send a request for approval to use the card to the management computer at the bank or credit company, creating a need to connect to a communication line and thus complicating the processing of card transactions.
If a user wants to use an installment payment plan via credit card, he/she makes an arrangement for direct debit with the credit company and the credit company automatically debits the fixed amount decided by the arrangement from the user's account on a fixed day every month. Therefore, the user must decide the amount of each installment in advance and it is difficult for him/her to decide the amount freely when making each payment.

Electronic money system and electronic money terminal device

Abstract: Instead of debiting the amount data equivalent to consumption from an information card 50, the present invention accumulates the amount data equivalent to consumption as data on the transaction history of installment payments, receives part or all of the accumulated installment balance as an installment amount, subtracts the received installment amount from the installment balance to determine a new balance, and thereby allows the user to pay any part of the installment balance as an installment amount.