In order to determine the actual position (A) of a geodetic measuring instrument (1) inside a dead range (T) wherein signals originating from a positioning system are shadowed, two reference structures (5) are detected from at least two known positions and the distances associated with the reference structures (5) are measured. Image information linked to said distance measurements is captured. Said information contains data on the arrangement of the reference structures (5). The actual position (1) can be derived from subsequent capture of the reference structures (5) from a position inside the dead range (T). Image processing methods are used advantageously to identify and measure the reference structures (5).

In many geodetic applications, methods and systems for position determination of a geodetic instrument are used, which methods and systems are based on the propagation of signals which can be shadowed and thus limited in their usability. Global positioning systems, such as, for example, GPS, GLONASS or the European Galileo system under construction are an example of such position-determining systems. These systems are based on the reception of satellite signals in a form as undisturbed as possible. In the immediate vicinity of obstacles, the reception of the signal may be limited or completely impossible owing to the shadowing effect thereof, so that a position determination is no longer possible by means of the system. A further example is the position determination of a reflector-bearing instrument comprising a theodolite or tacheometer. By means of a direction and distance measurement with the tacheometer to the geodetic instrument the position of the instrument can also be determined when the position of the tacheometer is known. A precondition for the measurement here is the visual link between the two components. If this link is interrupted, for example by growth or buildings in the region of sight, the position determination method fails.
Methods which are based on a determination of the position of the instrument itself relative to objects whose position is known are known for a position determination of the actual position, i.e. of the current location of the instrument, also in a dead range shadowed in such a manner. An example of this is the classical trilinear surveying method.
In many cases, a geodetic instrument has only a capability for distance measurement, or a measurement of angles cannot be carried out with the required precision or speed. In these cases, the position determination must be carried out by distance measurements alone. For this purpose, the distances to a plurality of points having a known position are measured, and the determination of the actual position can be effected by known methods, as also used, for example, in photogrammetry; correlation methods or correlation calculations are an example of this. The number of points required is dependent on the position thereof and the intended accuracy of the measurement. However, apart from particularly advantageous configurations, as a rule at least 3 or 4 points are required. If an angle is additionally taken into account, for example by additionally measuring the angle relative to the horizontal, the number of points can be reduced.
In order also to be able to use positions in the dead range for surveying by a purely distance-measuring method, it is first necessary to survey, from known locations, the reference points subsequently required for referencing.
A surveying device suitable for this purpose is described, for example, in European Patent EP 0 403 585 B1. The surveying device has a receiver for a satellite position-measuring system and a preferably electrooptical telemeter or telemeter based on the ultrasonic principle. Both components are mounted on a plumbing staff which can be precisely positioned with its plumbing staff tip and has an inclinometer and a display of the vertical alignment. Optionally, a sensor reacting to the earth's magnetic field may also be present. By means of at least 2 measurements to a point from 2 different known positions which are determined, for example, by the satellite position-measuring system the position of this point can now be determined even if it is within the dead range.
Conversely, the position of such a surveying device in the dead range can also be determined by measurements to a plurality of known points in the trilinear surveying method.
If surveying positions for the geodetic instrument which are both in spaces detected by the positioning system and in dead ranges are to be used in a survey, it is necessary, before using the dead range, to survey corresponding reference points for a subsequent determination of the actual position in the dead range. If it is intended to dispense with an explicit angle measurement, as a rule the distances must be measured at least for three to four points from at least three to four known positions, in order to permit an unambiguous position determination. The number of points actually required in each case is dependent on the position of the known points and any possible limitations for reducing ambiguity. In the case of three distance measurements to a point, a plane across which the position to be determined can be reflected is defined by the three known points. The resulting solution comprises two possible positions, of which, however, one position can generally be ruled out for plausibility reasons, for example because it would lie below the earth's surface, or because of simple further information, such as, for example, the distinction between north and south, which can also be made by means of a simple magnetic compass. An unambiguous determination with three known points is possible if advantageous geometrical conditions are present. This is the case, for example, if the position sought lies on a connecting line between two known points.
Depending on the circumstances of a measurement, at least between 9 and 16 distance measurements must therefore be carried out, for which in each case a correct assignment of measurement to reference point and known position must be effected. Carrying out such measurements manually therefore means a high handling effort and error-producing complexity.
Moreover, in order to achieve sufficient accuracy of the position determination, reference points suitable because of their geometrical arrangement have to be chosen. The position change between the known positions which is to be consciously implemented also has an adverse effect on the measuring process. Finally, the extension of the regions detected by the positioning system and shadowed must be actively observed with such methods of the prior art in order to be able to carry out in good time a change of the positioning method to be used.

Method and device for determining the actual position of a geodetic instrument


A switch assembly for microwave oven turntable is disclosed. The turntable comprises a base (4) and a platform (6) rotatably mounted thereupon. The platform (6) is adapted having a downward pripheral rim flange (36), along which an annular gear ring (38) is provided. A flange (20) extends outward from the base beyond and below the rim flange (20). A switch mechanism includes a rocker body (48) pivotally mounted to the flange (20) and adapted to pivot toward and away from the flange (36). A locking finger (60) extends under the rim flange (36) and upward into a parallel and adjacent relationship with the gear ring (38). The locking finger (60) is of triangular saw-toothed cross section defining an apex ridge (62) oriented toward the gear ring. The gear teeth of the gear ring (38) likewise have a saw-tooth configuration. Rocking actuation of the switch body causes the locking finger (60) to pivot toward and away from meshing engagement with the gear ring (38).

1. Field of the Invention
The subject invention relates generally to portable turntables for use in microwave ovens and specifically to switch assemblies for such turntables for controlling rotational movement.
2. The Prior Art
Portable turntables for microwave ovens are known and are commonly available in consumer markets. Such devices typically comprise a stationary base, a rotatable platform mounted to the base, and a drive motor. An on/off switching mechanism is generally provided to control the rotational movement of the platform relative to the base.
Achievement of a suitable on/off switch for microwave turntables has proven illusive. Such switching mechanicms must be convenient to operate, fail-safe, and compact in spacial dimension so as to fit within the smaller microwave oven cavities. Further, the switching mechanism must smoothly act to move the turntable in and out of its rotational mode of operation without requiring manual manipulation.
Various approaches at attaining an acceptable on/off switch for such turntables have been tried. For example, U.S. Pat. No. 4,434,343 teaches a rotatable platform component having a downward peripheral rim flange which incorporates inward directed gear teeth spaced therealong. A slidable lock is provided which extends below the downward rim flange and axially moves inward and outward whereby moving a rectangular meshing tooth in and out of engagement with the rim flange gear teeth.
While the above switch mechanism works well, it has certain deficiencies which prevent it from achieving all of the above-discussed performance requirements. First, operation of a sliding switch is cumbersome and can result in the turntable being pushed or pulled in jarring fashion. Undesired spillage of food stuffs supported by the turntable can result. Further, sliding actuation can cause the tooth of the sliding mechanism to stub against the gear teeth along the rim flange. Overcoming the impasse would require manual jogging of the lock mechanism and/or the turntable platform. However, such a procedure in the small confines of a microwave oven is awkward and can, again, result in foodstuff spillage.

Switch assembly for microwave oven turntable


A spile accommodating plastic lid, having a transverse closure wall, for sealed closure of jars, bottles, pouches and like fluent material conveyances that must be accessed for issuance of material contained therein. The closure wall is provided with a circular breakout area having a frangible periphery that facilitates mounting of a hollow push-in-place spile onto the lid, wherein, a tubular portion of the spile extends through the lid. The breakout area is constructed such that the frangible periphery yields and ruptures in a prescribed circular manner under push-in-place mounting of the spile. The breakout area is further constructed such that upon rupture of the frangible periphery it is pushed through and inwardly hinged so as to establish a hole having an inwardly turned periphery which functions as a biased annular lip seal that sealingly embraces the extended tubular portion of the spile. Hinging of the breakout area is facilitated by the frangible periphery being interrupted whereby a portion or the periphery is nonfrangible. The bole and the displaced breakout area remain linked by an unbroken span of plastic material that functions as a connecting hinge.

In general the present invention relates to a novel plastic lid used for sealing closure of a fluid filled replaceable pouch (bag) that is insertable in a reusable dispenser apparatus. More precisely the present invention pertains to a novel closure lid that is provided with a peripherally frangible breakout area, that is configured to separate in a prescribed manner, to produce a sealable circular opening in the lid. The lid is of such plastic material, for example high density polyurethane, as to possess some elastomeric qualities.
Heretofore there has been a need for a prefilled and lidded pouch (plastic bag), for containment of a dispensable fluid product, that can be conveniently placed in reusable dispensers, bottles and the like. While several versions of prefilled pouches inventions have recognized the advantages of a drop in place pouch they are still deficient since their lids must be removed or pierced in order to gain access to the contents of the pouch. Either approach, removal or piercing, is prone to inconvenient handling spillage that must be dealt with. Thus, present day needs for efficiency and convenience have not previously been satisfied. The present invention overcomes these deficiencies and in so doing provides a simple tamper evident closure lid as well.
The present invention distinguishes from prior art in that it discloses a novel lid having a hinged breakout area, which is defined by a frangible circular periphery, that is of sufficient strength to ensure against being inadvertently ruptured and of sufficient weakness to separate, upon demand, in a prescribed manner to produce a sealable circular opening.
In typical use the present invention lid is disposed on and sealingly closes a collapsible pouch, containing a dispensable product, which serves as a replaceable prefilled refill cartridge employed in a reusable dispenser. The reusable dispenser preferably consist of a bottle-like structure, having an externally threaded open end, and a corresponding screw-on cap that includes an aspirator device that communicates with contents of the pouch.
Said cap also includes a depending tubular spile that provides a flow through passageway from the interior of the pouch to said aspirator device. The spile is provided with a blunt distal end, having a circumferential diameter that is somewhat larger then that of said break out area. The spile is situated so as to be in axial alignment with the breakout area of the lid.
An act of tightening of said cap onto the bottle-like structure causes the distal end of the spile to bear pressure against said breakout area periphery, effectuating a seal and causing said periphery to stretch and yield, so as to release the breakout area. With said cap fully tightened into place, said spile sealingly protrudes through a resulting circular opening in the lid and the breakout area is hinged inwardly.
The circumferential diameter of the spile distal end, being larger than the breakout area periphery, causes said opening to have a downwardly flaired curvature whereas, the laying circular edge of said opening faces down providing the characteristics of an annular lip seal. The importance of the lip seal characteristic is that the opening cannot be inverted, by internal pressure produced within a sealingly lidded pouch, when the spile is in place. It is also important to have said faying edge face down so that said flair curvature conformingly engages the outer surface of the spile to effectuate a seal. In addition the elastomeric quality of the lid material is such that the flair curvature maintains a biased sealing engagement, analogous with a lip seal, with respect to the spile.
It needs to be realized that the structure of the present invention lid is such that in use the lid is capable of being transformed from a closure structure that reliably obturates access to contents of a container to a closure structure having an access opening that is characteristic of an elastomeric lip seal.
An advantage of the present invention is that it, now for the first time, provides a convenient and efficient method for use of prefilled flexible pouches (bags), as replaceable cartridges, in reusable dispensers. The pouch, in an unopened state, is simply placed in a reusable dispenser to provide a dispensing system that is immediately ready to issue contents from a pouch when the cap is fully tightened into place. Since there is no pre-opening operation required for the pouch, there is no risk of an inconvenient spillage.
The present invention facilitates reuse of major components of the dispenser system by providing a pouch closure lid that enables a product filled pouch to be placed, unopened, in a dispenser and be automatically opened when the dispenser cap is put into place. Reuse of the dispenser is convenient for consumers and it effectively contributes to waste management programs through source reduction of plastic materials.
It is further noted that the teachings of the present invention are not limited to prefilled pouch applications, they are applicable to lid closures for various types of conveyors, such as bottle, jars, drums, cans and tubes, used for containment of fluid material.


An automatic document feeder of an electrophotographic copying apparatus includes a feeding tray, a device for feeding to an exposing station one document sheet after another from a stack of document sheets piled on the feeding tray by starting with the lowermost document sheet of the stack, and a device for returning the document sheets to the feeding tray and placing same on the uppermost document sheet of the stack after the document sheets have been treated for exposure. The automatic document feeder further includes a sensor for sensing that a job sheet is disposed beneath the lowermost document sheet of the stack of document sheets on the feeding tray. The job sheet is placed beneath the lowermost sheet of the stack of a series of document sheets piled on the feeding tray by successively stacking the document sheets with the first document sheet of the series constituting the lowermost document sheet of stack or placed over the uppermost document sheet of the stack which is constituted by the last document sheet of the series, and has a mark on its surface for controlling the automatic document feeder and a main body of the copying apparatus.

This invention relates to an automatic document feeder suitable for use with an electrophotographic copying apparatus for automatically feeding to an exposing station one document sheet after another from a stack of document sheets piled on a feeding tray by starting at the lowermost document sheet of the stack and returning the document sheets to the stack on the feeding tray and placing them on uppermost document sheet of the stack after the document sheets have been treated for exposure.
When a document consisting of a series of document sheets of several pages is copied by an electrophotographic copying apparatus, it is troublesome to repeatedly perform the operation of placing one document sheet on a contact glass member, setting a pressing plate thereon, removing the document sheet after it has been treated for exposure and replacing the illuminated document sheet for exposure by another document sheet of the next following page. To eliminate the need for the operator to perform this troublesome operation, proposals have been made to use an automatic document feeder which automatically feeds one document sheet after another from a stack of document sheets on a feeding tray and automatically ejects document sheets that have been treated for exposure.
When a document consisting of a multiplicity of document sheets of several pages is copied to produce a plurality of copies of the document, it is usual practice to place one document sheet on the contact glass member and produce a desired number of copies of the document sheet and repeat the same operation, until all the document sheets have been treated. The copies of the document sheets produced by the aforesaid operation and ejected from the copying apparatus are sorted either manually or by using a sorter to produce a desired number of copies of the document each copy consisting of copies of the document sheets arranged in the order of pages. In the automatic document feeder described hereinabove, the time required for feeding a document sheet to a predetermined position in an exposing station is short and substantially as long as the time required for a scanner to be restored to its original position. Therefore, if only one copy is produced each time one document sheet is fed to the exposing station and this is repeated until a copy each of all the document sheets is produced, then it is possible to produce a required number of copies of the document each copy consisting of copy sheets of the document sheets arranged in the order of pages merely by repeating the aforesaid operation a number of times corresponding to the desired number of copies of the document to be produced while eliminating the need to perform the operation of sorting the copies in the order of pages.
When this operation is performed, it will be possible to produce the required number of copies of the document by repeatedly feeding and returning the document sheets a number of times corresponding to the required number of copies of the document, if one document sheet after another is fed from the feeding tray by starting at the lowermost document sheet of the stack to the exposing station and the document sheets are returned to the feeding tray and placed on the uppermost document sheet of the stack after exposing is finished.
This type of automatic document feeder is known and disclosed in Japanese Patent Publication No. 56-467 corresponding to (U.S. patent application Ser. No. 671,867, filed Mar. 30, 1976) and Japanese Patent Publication No. 56-40338 corresponding to (U.S. patent application Ser. No. 523,610, filed Nov. 13, 1974), for example.
When a plurality of copies of a document consisting of a series of document sheets of continuously numbered pages are produced by using this type of automatic document feeder, it is necessary to monitor the feeding of the document sheets to the exposing station to determine how many number of times the document sheets have been fed to the exposing station and returned therefrom. To this end, the automatic document feeder disclosed in the Japanese patent publications referred to hereinabove is provided with a partition plate inserted into the feeding tray across the rear wall. A series of document sheets piled in a stack in which the first page of the series forms the lowermost document sheet and the next following pages are piled thereon in an orderly manner are initially placed on the feeding tray in such a manner that the partition plate is placed on the document sheet or the last page of the series. The document sheets are successively fed to the exposing station from the feeding tray by starting at the lowermost document sheet or the first page of the series and returned to the feeding tray, and when all the document sheets have been fed and no document sheet is left under the partition plate, the partition plate is detected by a sensor and a document sheet feeding completion signal is produced. When only one copy each of the series of document sheets is produced, the automatic document feeder is rendered inoperative by this signal. When a plurality of copies are produced, the partition plate is withdrawn from below the stack of document sheets when this signal is produced and placed on top of the stack of document sheets again. This operation is repeated a number of times corresponding to the desired number of copies to be obtained, so that the automatic document feeder is rendered inoperative after a predetermined number of copies of the document have been produced following sensing of the partition plate a predetermined number of times.
In the automatic document feeder of the aforesaid construction, a mechanism of complex construction should be provided for moving the partition plate each time the operation of feeding the series of document sheets to the exposing station is finished. Also, means should be provided for the operator to input to automatic document feeder data on the number of copies to be produced and whether only one surface or both surfaces of each document sheet should be copied.


A hydraulic unit of the type including a cylinder block (19) rotatably disposed adjacent a valve plate (51;61) having inlet ports 41a, 41b, and 41c, and further having outlet ports 43a, 43b, and 43c. Disposed between the individual inlet and outlet ports are web portions, having nominal cross-sections and flow restrictions. In one embodiment (FIG. 3), there is a modified web portion (55) toward the trailing end of the outlet port, and in the other embodiment (FIG. 7), there is a modified web portion (65) toward the leading end of the outlet port. In either case, the web portion has its cross-section or flow restriction modified to move the resultant force on the swashplate (33) in a direction tending to reduce the moments on the swashplate, and therefore, reduce the operator effort required to move or maintain the control lever.

The present invention relates to variable displacement hydraulic pumps having a rotating group of the axial piston type, and more particularly, to an improved valve plate for use in such pumps.
Among the types of axial piston pumps known to those skilled in the art is one in which the tiltable swashplate includes a pair of transversely opposed trunnions which are rotatably supported, relative to the pump housing, by suitable bearing means. A pump of the type described is sometimes referred to as a "trunnion pump." The other type of axial piston pump in widespread commercial use is of the "swash and cradle" type, as illustrated and described in U.S. Pat. No. 5,590,579, assigned to the assignee of the present invention and incorporated herein by reference. Those skilled in the art will understand that the present invention is illustrated and described in connection with a trunnion pump, but is equally applicable to a swash and cradle type pump.
In a typical axial piston pump, whether of the trunnion or swash and cradle type, there is a rotating cylinder barrel which includes a plurality (typically, an odd number) of reciprocating pistons. The pistons engage the cam or swashplate, the position of which may be fixed, but more typically, may be varied to adjust the displacement of the pump. The end of the cylinder barrel opposite the swashplate could be seated directly against the backplate, but more typically, is seated against a valve plate. The valve plate defines a fluid inlet and a fluid outlet which, in turn, are connected, through passages in the backplate, to the pump inlet port and the pump outlet port, respectively, defined by the pump housing.
In the early days of axial piston pumps, the valve plate merely defined a pair of arcuate, substantially identical ports, with each port being open, through the thickness of the valve plate, and throughout the entire circumferential extent of the port, which would typically be about 150.degree. or 160.degree.. See for example U.S. Pat. No. 2,915,985, incorporated herein by reference. However, in valve plates of the type utilized in the cited patent, there were concerns regarding the strength and durability of the valve plate, in view of the continuous, arcuate form of the inlet and outlet. Typically, there was no substantial clamping load applied axially on the valve plate, and therefore, the pressurized fluid in the high pressure port would apply a radial load to the portion of the valve plate radially outward from the port, and could cause the plate to fail.
The concern regarding the strength of the valve plate led those skilled in the art to replace each of the individual arcuate ports (inlet or outlet) with a series of separate ports, with each adjacent port being separated by a "web" portion, which would typically be of the same material and thickness as the rest of the valve plate. Typically, each port (inlet or outlet) would consist of two or three individual ports arranged such that communication of the port with a particular kidney of the cylinder barrel would begin at the same time and end at the same time as when the port comprised one continuous port. In other words, the web portions were simply locations in the port where the port was discontinued, and were included to add strength to the valve plate. See for example U.S. Pat. No. 3,249,061, incorporated herein by reference.
Over the years, those skilled in the art have modified the inlet and outlet ports of the valve plate in various ways, typically, in an attempt to optimize valve timing in such a way as to reduce the noise generated by the pump. As used herein, the term "valve timing" refers to the relationship of each piston in the cylinder barrel, and its associated kidney (and when expansion and contraction occurs) relative to the beginning and end of communication of the cylinder kidney with the inlet and outlet ports in the valve plate.
Another important performance criteria of axial piston pumps is that of swashplate moments, i.e., forces on the swashplate tending to bias the swashplate back toward, or away from, the neutral (zero displacement) position. Swash moments is an especially significant issue in the case of manually controlled axial piston pumps, i.e., those wherein swashplate position is manually selected by the operator, for example, by means of movement of a handle or control lever, external to the pump, which is connected to the swashplate such that the movement of the handle directly and mechanically moves the swashplate. Typically, the control lever, external to the pump, includes a biasing spring, tending to bias the lever back toward the neutral position, the force of the biasing spring normally being selected such that it compensates for the "worst case" moments on the swashplate. Thus, the intention is that the force to be exerted by the operator is always in the same direction, i.e., the spring force is great enough that the operator is required to push on the lever under one particular operating condition, to achieve a certain pump displacement, but is required to pull on the lever under another operating condition, to achieve the same pump displacement.
It has been known to those skilled in the art that there are forces on the swashplate caused by the pressurized pistons, and these forces generate a resultant force on the swashplate. The magnitude of the resultant force, and its distance from the pivot axis of the swashplate, determine the moments on the swashplate, and in turn, the amount of force, and the direction of the force, which must be exerted by the operator in order to move the swashplate to change the pump displacement, or even to maintain the swashplate in its current position. As will be illustrated in greater detail subsequently, with the swashplate displaced in a "forward" direction (as shown in FIG. 1), having the resultant force located below the pivot axis (a "positive" moment) will tend to drive the swashplate back toward the neutral position, whereas, having the resultant force located above the pivot axis (a "negative" moment) will tend to drive the swashplate toward greater displacement.
It has also been generally understood by those skilled in the art that valve plate timing would have an impact on the location of the resultant force. However, changing valve plate timing as a way of trying to reduce swash moments has the disadvantage that, in a certain application, the change in valve timing needed to reduce swash moments may result in noisier pump operation, or pump operation which is less efficient in the sense of permitting cross port leakage, which is well known to those skilled in the art.

Axial piston pump and improved valve plate design therefor


An image forming apparatus has a photoreceptor having a image carrying surface, an exposing device to imagewise expose the image carrying surface to form a latent image, and a developing device to develop the latent image to form a toner image on the image carrying surface. The exposing device has a light source which emits a light beam, a deflector which deflects the light beam to form a scanning line with the light beam on the image carrying surface, a cylindrical lens between the deflector and the image carrying surface which focuses the light beam on the image carrying surface, and an adjusting mechanism which adjusts an inclination of the scanning line and adjusts variance in magnification of an image on the scanning line.

The present invention relates to an image forming apparatus for forming an image wherein a photoreceptor is scanned to be exposed to light by a light beam, and to an assembling method of an exposure unit in the image forming apparatus.
In the image forming apparatus for forming an image wherein a photoreceptor is scanned to be exposed to light by a light beam, accuracy of incident position of the light beam on the photoreceptor has an influence on image quality. Therefore, an exposure unit is structured so that the light beam may enter at high accuracy.
In a color image forming apparatus for forming a color image by conducting a plurality of exposures, forming a plurality of images and thereby by superposing the plural images, in particular, it is requested to keep the position stated above accurately.
Typical one that conducts scanning exposure with a light beam is an exposure unit employing a laser, and with respect to adjustment of the position stated above in a laser exposure unit, there is disclosed in U.S. Pat. No. 2,570,176 official gazette, for example, an adjustment mechanism for adjusting a position and an angle of the exposure unit having a laser light source and a scanning exposure optical system in X, Y and Z directions. This adjustment mechanism adjusts at two points representing both ends of each side of the square exposure unit for each of X, Y and Z directions, and thereby adjusts the incident position of the light beam on the photoreceptor.
Each of many color image forming apparatuses is equipped with a plurality of exposure units which form a plurality of color images, and these exposure units are provided in the image forming apparatus at high positional accuracy. In particular, it is required that relative positional accuracy between the exposure units is high. If the positional accuracy between the exposure units is not satisfactory, displacement is caused between color images to cause doubling, resulting in deterioration of image quality. The positional relationship between exposure units needs to be maintained during the operation period of the image forming apparatus.
To satisfy the conditions about positions of the exposure units, a plurality of exposure units have been combined with UV adhesive agents, for example.
In the adjustment mechanism disclosed in the aforesaid patent publication, there are provided 6 adjustment means in total, because adjustment is made at two points for each of X, Y and Z directions. Therefore, the adjustment is complicated. Further, there has not been disclosed a concrete adjustment mechanism capable of attaining simple structure and high adjustment accuracy, in the prior art.
Further, in the fixing means to fix between exposure units by adhesive agents, a great many hours are needed for securing desired strength, which has been a problem in manufacture.
An object of the invention is to solve the aforesaid problems in conventional image forming apparatuses employing a light beam.
In order to attain the above-described objects, the structure of this invention has been made as follows:
An image forming apparatus, comprising:
a photoreceptor having an image carrying surface;
an exposing device to imagewise expose the image carrying surface to form a latent image; and
a developing device to develop the latent image to form a toner image on the image carrying surface;
the exposing device comprising:
a light source to emit a light beam;
a deflector to deflect the light beam so as to form a scanning line with the light beam on the image carrying surface;
a cylindrical lens provided between the deflector and the image carrying surface and to focus the light beam on the image carrying surface; and
an adjusting mechanism to adjust an inclination of the scanning line and to adjust variance in magnification of an image on the scanning line.
Further the above objects may be attained by the following structures.
(Structure 1)
An image forming apparatus having therein exposure units each being provided with a laser light source and a scanning optical system that deflects light coming from the light source and emits scanning light beam, the exposure units being supported on at least a first supporting point, a second supporting point and a third supporting point, wherein a first adjustment means that adjusts an inclination of the scanning light beam in the primary scanning direction is provided in a first supporting section where the first supporting point is provided, and the inclination in the primary scanning direction is adjusted only by adjustment of the first adjustment means.
(Structure 2)
An image forming apparatus having therein exposure units each being provided with a laser light source and a scanning optical system that deflects light coming from the light source and emits scanning light beam, the exposure units being supported on at least a first supporting point, a second supporting point and a third supporting point, wherein a second adjustment means that adjusts variation in magnification of the scanning light beam in the primary scanning direction is provided in a second supporting section where the second supporting point is provided, and the variation in magnification is adjusted only by adjustment of the second adjustment means.
(Structure 3)
The image forming apparatus according to Structure 1 above having therein exposure units each being provided with a laser light source and a scanning optical system that deflects light coming from the light source and emits scanning light beam, the exposure units being supported on at least a first supporting point, a second supporting point and a third supporting point, wherein a second adjustment means that adjusts variation in magnification of the scanning light beam in the primary scanning direction is provided in a second supporting section where the second supporting point is provided, and the variation in magnification is adjusted only by adjustment of the second adjustment means.
(Structure 4)
An image forming apparatus according to Structure 1 above having therein exposure units each being provided with a laser light source and a scanning optical system that deflects light coming from the light source and emits scanning light beam, the exposure units being supported on at least a first supporting point, a second supporting point and a third supporting point, wherein a first supporting section in which at least one supporting point among three supporting points is provided a spherical body bearing that supports the exposure unit rotatably in all directions.
(Structure 5)
The image forming apparatus according to Structure 1 or Structure 3 above, wherein the first supporting section is provided with a spherical body bearing that supports the exposure unit rotatably in all directions.
(Structure 6)
The image forming apparatus according to Structure 1 or Structure 3 above, wherein a movement of the first supporting point is conducted around a straight line passing through the other two supporting points which serves as the axis, and at least one of the other two supporting points can move in the direction that is mostly perpendicular to the movement direction of the first supporting section.
(Structure 7)
The image forming apparatus according to Structure 2, wherein the second supporting section is provided with a spherical body bearing that supports the exposure unit rotatably in all directions.
(Structure 8)
The image forming apparatus according to Structure 2 or Structure 3 above, wherein a movement of the second supporting point is a rotation around the first supporting point, and the second supporting section is provided with a slide which makes the exposure unit to move in the direction of a normal line for the direction of the aforesaid rotation.
(Structure 9)
The image forming apparatus according to either one of Structure 1-Structure 4 above, wherein the third supporting point is made to be a fixed point.
(Structure 10)
The image forming apparatus according to Structure 9, wherein the third supporting point is provided on the plane that mostly includes an optical axis of the scanning optical system and is mostly perpendicular to the scanning plane.
(Structure 11)
The image forming apparatus according to Structure 9 or Structure 10, wherein the first supporting point and the second supporting point are provided respectively on both end portions of an optical path formed by the scanning optical system.
(Structure 12)
The image forming apparatus according to either one of Structure 9-Structure 11 above, wherein the first supporting point and the second supporting point are provided respectively at positions which are mostly symmetrical about an optical axis of the scanning optical system.
(Structure 13)
The image forming apparatus according to Structure 4 above, wherein the spherical body bearing has a separation preventing member that prevents separation of the supporting spherical body.
(Structure 14)
The image forming apparatus according to Structure 13 above, wherein the separation preventing member is elastic.
(Structure 15)
The image forming apparatus according to Structure 13 or Structure 14 above, wherein the spherical body bearing supports the spherical body at three points thereon, and the separation preventing member makes the spherical body to be in pressure contact with the spherical body bearing by touching at least one point on the spherical body.
(Structure 16)
The image forming apparatus according to Structure 13 or Structure 14 above, wherein the spherical body bearing supports the spherical body in the shape of a circular ring, and the separation preventing member makes the spherical body to be in pressure contact with the spherical body bearing by touching at least one point on the spherical body.
(Structure 17)
The image forming apparatus according to either one of Structure 2-Structure 4 and Structure 9-Structure 16 above, wherein a distance keeping means that keeps a distance between the exposure unit and the second supporting section and an elastic member that presses the exposure unit against the second supporting section are provided in the vicinity of the second supporting section in which the second supporting point is provided.
(Structure 18)
The image forming apparatus according to either one of Structure 1-Structure 17, wherein the first supporting section is composed of a driving screw and an engagement plate that engages with the driving screw, and the first adjustment means is composed of the driving screw, the engagement plate and a driving source that drives the driving screw.
(Structure 19)
The image forming apparatus according to either one of Structure 1-Structure 18, wherein the second supporting section is composed of a driving screw and an engagement plate that engages with the driving screw, and the second adjustment means is composed of the driving screw, the engagement plate and a driving source that drives the driving screw.
(Structure 20)
The image forming apparatus according to Structure 18 or Structure 19, wherein the engagement plate stated above is composed of two sheets which engage with the driving screw respectively in two directions which are opposite to each other.
(Structure 21)
The image forming apparatus according to Structure 20, wherein the two engagement sheets are formed as protruded sections extended from one sheet of common base section.
(Structure 22)
The image forming apparatus according to Structure 20 or Structure 21, wherein the two engagement sheets engage with the driving screw at two positions which are deviated in terms of phase by approximately a half of a pitch of the driving screw each other.
(Structure 23)
The image forming apparatus according to either one of Structure 1-Structure 17, wherein the first supporting section is composed of a driving male screw and an engagement block which has a female screw that engages with the driving male screw and is fixed on the exposure unit, and the first adjustment means is composed of the driving male screw, the engagement block and a driving source that drives the driving screw.
(Structure 24)
The image forming apparatus according to either one of Structure 1-Structure 17, wherein the second supporting section is composed of a driving male screw and an engagement block which has a female screw that engages with the driving male screw and is fixed on the exposure unit, and the second adjustment means is composed of the driving male screw, the engagement block and a driving source that drives the driving screw.
(Structure 25)
The image forming apparatus according to Structure 23, wherein an engagement clearance between the driving male screw and the female screw is made to be 1.5 times the maximum position correction amount of the exposure unit or more, so that rotating operations of the driving male screw in the first supporting section may not be interrupted.
(Structure 26)
The image forming apparatus according to Structure 24, wherein an engagement clearance between the driving male screw and the female screw is made to be 1.5 times the maximum position correction amount of the exposure unit or more, so that rotating operations of the driving male screw in the second supporting section may not be interrupted.
(Structure 27)
The image forming apparatus according to either one of Structure 23-Structure 26, wherein the engagement block has two connecting members protruded in the direction perpendicular to a rotary axis of the driving male screw, and the engagement member is combined with the exposure unit by the connecting member.
(Structure 28)
The image forming apparatus according to either one of Structure 1-Structure 17, wherein the first supporting section is composed of a driving male screw, an engagement block that engages with the driving male screw and a driving source that drives the driving screw, and there are provided on the engagement block a hole through which the driving male screw enters and an engagement member that has a tip portion engaging with the driving male screw and engages with the engagement block through screw.
(Structure 29)
The image forming apparatus according to either one of Structure 1-Structure 17, wherein the second supporting section is composed of a driving male screw, an engagement block that engages with the driving male screw and a driving source that drives the driving screw, and there are provided on the engagement block a hole through which the driving male screw enters and an engagement member that has a tip portion engaging with the driving male screw and engages with the engagement block through screw.
(Structure 30)
The image forming apparatus according to Structure 1 or Structure 3, wherein a plurality of the exposure units are provided, and the first adjustment means stated above is provided on each of the plural exposure units.
(Structure 31)
The image forming apparatus according to Structure 1 or Structure 3, wherein a plurality of the exposure units are provided, and the second adjustment means stated above is provided on each of the plural exposure units.
(Structure 32)
The image forming apparatus according to Structure 3, wherein a plurality of the exposure units are provided, and the first adjustment means and the second adjustment means both stated above are provided on each of the plural exposure units.
(Structure 33)
The image forming apparatus according to Structure 1 or Structure 3, wherein the first adjustment mean has a driving source composed of a motor.
(Structure 34)
The image forming apparatus according to Structure 2 or Structure 3, wherein the second adjustment mean has a driving source composed of a motor.
(Structure 35)
The image forming apparatus according to Structure 1 or Structure 3, wherein the first adjustment mean has a driving source composed of a layered piezoelectric actuator.
(Structure 36)
The image forming apparatus according to Structure 2 or Structure 3, wherein the second adjustment mean has a driving source composed of a layered piezoelectric actuator.
(Structure 37)
An image forming apparatus having therein an exposure unit composed of a laser light source and a scanning optical system that deflects light coming from the laser light source and emits a scanning beam, a first supporting means that supports the exposure unit rotatably, a second supporting means that is in a form of a circular arc whose center is the first supporting means and supports the exposure unit movably along the circular arc, and a magnification adjustment means that adjusts variation of magnification in the primary scanning direction of the scanning optical system by the rotation around the first supporting means.
(Structure 38)
An image forming apparatus having therein an exposure unit composed of a laser light source and a scanning optical system that deflects light coming from the laser light source and emits a scanning beam, and an inclination adjustment means supporting the exposure unit, having a supporting shaft that is almost in parallel with an optical axis of the scanning optical system and adjusting an inclination in the primary scanning direction by rotating the exposure unit on the center of the supporting shaft.
(Structure 39)
An assembling method of an exposure unit for assembling the exposure unit for an image forming apparatus having therein a photoreceptor, a charging unit that charges the photoreceptor, a exposure unit that conducts scanning exposure on the photoreceptor with a light beam to form an electrostatic latent image and a developing unit that develops the electrostatic latent image formed on the photoreceptor, and having at least a plurality of the exposure units, wherein each of the exposure units is attached to a supporting means so that a position of the exposure unit is corrected, and then, the clearance formed between the plural supporting means is filled with melted resins so that the exposure units and a distance between the exposure units are fixed.
(Structure 40)
The assembling method of an exposure unit according to Structure 39, wherein each of the plural supporting means has a plane crossing in the direction in which the plural exposure units are separated each other, and mutual exfoliation is prevented by resistance of the resin itself filled in the clearance formed by the crossing planes.
(Structure 41)
The assembling method of an exposure unit according to Structure 39 or Structure 40, wherein the supporting means is made of resin, and a space between the supporting means is filled with resin that is the same in terms of a type as the resin of which the supporting means is made, and thereby the supporting means are combined each other through their clearances.
(Structure 42)
An assembling method of an exposure unit for assembling the exposure unit for an image forming apparatus having therein a charging unit that charges the photoreceptor, an exposure unit that conducts scanning exposure on the photoreceptor with a light beam and a plurality of image forming sections each having a developing unit that develops an electrostatic latent image formed on the photoreceptor which are arranged to face the photoreceptor, wherein each of the exposure units is attached to a supporting means so that a position of the exposure unit is corrected, and then, the clearance formed between the plural supporting means is filled with melted resins for fixing the position so that the exposure units and a distance between the exposure units are fixed.
(Structure 43)
The assembling method of an exposure unit according to Structure 42, wherein each of the plural supporting means has a plane crossing in the direction in which the plural exposure units are separated each other, and mutual exfoliation is prevented by resistance of the resin itself filled in the clearance formed by the crossing planes.
(Structure 44)
The assembling method of an exposure unit according to Structure 42 or Structure 43, wherein the supporting means is made of resin, and a space between the supporting means is filled with resin that is the same in terms of a type as the resin of which the supporting means is made, and thereby the supporting means are combined each other through their clearances.

Image forming apparatus having light beam adjusting mechanism


An apparatus for removing dirt from an exposed film as it is advanced to an image developing unit includes a scrub roll with a spongy surface and a second roll in engagement therewith for transporting the film. A conduit with perforations directed at the scrub roll is positioned thereabove and is connected to a source of flushing liquid. The transport and scrub rolls are driven co-currently at different surface speeds to generate a scrubbing, shearing action along with simultaneous wetting of the film surface to remove most of any dust or dirt previously carried by or embedded in the surface of the film.

In the graphic arts industry, and particularly in lithography, printing plates are usually imaged by exposing them through a film containing a line or half-tone image. At the outset, the original material or "copy" may be in the form of a continuous tone photograph, drawing or type proof. This is then reduced to a black and white transparency of the correct size using a camera or scanner and, during this step, continuous tone images may be converted to half-tone. This transparency, however, is seldom in a form suitable for the exposure of a plate and a contact or first generation copy is made, for example, to combine line and half-tone films in register, to produce a single film from stripped flats, to strengthen half-tone dots or to make spreads or chokes. The first generation copy may then be printed on another film in contact to give a second generation copy, and this even to a third generation before a film suitable for use in plate exposure is obtained.
In the contact printing operation, a target film is placed over a sheet of unexposed film in a vacuum frame. After vacuum has been applied and the films are in good contact, the film is exposed and then processed. Contact printing is usually carried out with silver halide films that can be either negative or positive working. However, photosensitive films, either photohardenable or photosolubilizable, can also be used. They consist typically of a transparent polyethylene terephthalate support, on one side of which is an opaque photosensitive layer covered by a thin oxygen impermeable barrier layer. Actinic light forms relatively soluble and insoluble regions in the photosensitive layer and the soluble regions can then be washed out in a suitable solvent to leave a relief image of the target. It was found in practice that the use of such films often results in an unacceptably high level of pin holes in opaque areas of copies which resulted from residual opaque specks in supposedly clear areas of the preceding generation.
Pinholes in opaque areas result from dirt carried by or pressed into the surface of soluble regions of the preceding generation, for example, during vacuum draw down. Such dirt can retard the penetration of developer in its immediate area and result in a residual speck of underdeveloped photosensitive material which will copy as a pinhole.


The invention relates to a motor-driven hand tool for machining of workpieces, in particular planar workpieces, having a guide surface which can be placed on the workpiece to be treated, and a face milling cutter for processing which projects past the guide surface, and which has an axis of rotation extending perpendicularly to the guide surface.

A quite frequent requirement is for having to remove a comparatively thin layer, which can be a layer of old lacquer or a damaged surface layer of the workpiece, from a planar workpiece, for example a table top, a door, a window frame or a parquet floor. Grinding machines, such as belt grinders or orbital sanders, have been employed for this purpose for a long time, but deeper scratches, dents or similar damage cannot be removed by these devices or they can be removed only with a large expenditure of time. The troubling generation of dust must always be tolerated with grinding work. The non-directional cutting edges of the grinding bodies have been shown to be disadvantageous for some types of application. In addition, under strong pressure it is particularly difficult for an untrained layman to guide a grinder, in particular a belt grinder, free of tilt and evenly, so that a level surface is generated. Processing by machining and cutting is given preference for the above mentioned reasons.
A manual planing machine with a roller-shaped planing tool is known from German Patent Publication DE 35 41 728 A1, . This machine defines an axis of rotation which extends parallel with the surface to be worked. However, manual planing machines of this type have the disadvantage that for all practical purposes they can only be moved in the circumferential direction of the planing roller, which extends parallel with the workpiece surface.
Finally, a device defining the species and available in commerce is known by the name "Lamello-Plano", in which a face milling cutter with an axis of rotation extending perpendicularly with the workpiece surface is provided. However, this tool is suitable and intended for a purpose different from that of the present invention. The tool is not intended to be employed for planar removal of a surface layer, but for the removal of a spatially limited overhang, such as is created, for example, by the insertion of a filler claw into a cut-out irregularity of the workpiece. The face milling cutter is disposed with the guide surface to be placed on the workpiece to be processed in an open-edged recess, so that the overhang extends into the cutting range of the face milling cutter in this open-edged recess. When using the known hand tool in accordance with this purpose, the face milling cutter is placed back away from the guide surface. This known hand tool has the further disadvantage that, aside from its purpose of use which is different from that of the present invention, working up to an area of the inner edge is not possible, because housing elements make the approach of the face milling cutter to an edge or step area impossible.
Surface milling cutters are also known which, however, are used in accordance with their purpose for machining surface profiles, such as grooves, dovetailed guides or the like, and furthermore do not permit surface treatment right up to a fold, and edge or a step.


An inventive encoding system that expects, accepts and interprets both normal and abnormal states of a sensor array, and that preferably further recognizes a zero state as a malfunction. The system is xe2x80x9cabsolute,xe2x80x9d in that it allows detection of the best fit detectable position of a movable object with an accuracy equal to the resolution which is equal to one-half the physical displacement of sensors or sources in an array. Such absolute references may be used to define a position detector which properly detects the position of an object after power is applied, even though the object may have moved further after power is removed. As a result, the inventive encoder does not require a battery back-up to detect position accurately after a power failure. This functionality is highly advantageous when detecting shaft position of a multi-turn shaft. The inventive encoding system is also scalable so that there are few limitations in deployment. Truth table logic is employed in a logic function that is designed to implement the foregoing attributes of the inventive encoding system.

This application relates generally to encoding systems using truth table logic, and in particular to encoding of, for example, detected array states into a digital representation having improved reliability and predictability.
The present invention includes a sensor array encoding system that is specifically designed for implementation on the absolute position detector described in commonly-assigned, co-pending U.S. patent application xe2x80x9cABSOLUTE POSITION DETECTOR INTERPRETING ABNORMAL STATES,xe2x80x9d Ser. No. 09/595,368, filed Jun. 15, 2000 (hereafter xe2x80x9cAPD interpreting Abnormal Statesxe2x80x9d). It will be appreciated, however, that the inventive encoding system disclosed herein is much broader in concept, and is in no way limited to a specific implementation such as is described in APD interpreting Abnormal States. The inventive encoding system has many other applications, including in encoding other suitable sensor array implementations in which abnormal states are accepted rather than rejected.
Encoding systems, such as Binary code or Gray code, for example, are known in the art. FIG. 1A illustrates a conventional linear electrical contact encoder using Gray code. Encoder plate 10 has a conductive encoding pattern 11 equivalent to Gray code etched or clad to an insulating material 12. The conductive pattern is normally connected to the power supply ground 13 while a positive current is applied to each of the contact brushes or pins 14A through 14D. As the encoder plate 10 or the contact pins 14A through 14D are moved, if any one pin 14 contacts a conductive area 11 of the plate 10, a one (low true) output is generated in the output truth table 15. While a pin 14A through 14D is contacting the insulating portion 12 of the plate 10, a zero output is generated in the output table 15. The four contact pins 14A through 14D and the encoding plate 10 as illustrated on FIG. 1A will be understood to generate sixteen distinct codes for each of the sixteen steps as shown in the truth table 15.
Referring now to FIG. 1B, Gray code, as with most other conventional encoder codes, must then be decoded into a code recognizable by computers or other devices such as a displays or printers. Since computers are based on the binary numbering system, a conversion to binary code is usually the most logical. Encoded data (Gray code) from the encoder is input to the decoder 16 and the outputs of the decoder is binary code 17 as shown in the truth tables 18 of FIG. 1C. It will be understood on FIG. 1C that exemplary use is made of four bits of binary code represented by four bits of Gray code to encode the sixteen steps (notated in hexadecimal) in the encoder depicted in FIG. 1A. This exemplary use of four-bit binary code relating to a hexadecimal number of steps will be continued, although it will be understood that the conventional encoding and decoding principles described with reference to FIGS. 1A through 1C may be scaled larger or smaller.
Referring now to FIG. 2A, it is also known in the art that the linear encoding pattern 11 as shown on FIG. 1A may be represented as a circular pattern 21 on endless loop encoder disk 20. The contact pins 24 are shown at the datum zero position 25 with the least significant bit (LSB) at the outer edge and the most significant bit (MSB) at the enter-most ring of the disk. This encoded disk will produce the same Gray code as shown in the truth table 15 of FIG. 1A and may be decoded to binary using a decoder 16 as depicted in FIG. 1B to yield the truth tables 18 of FIG. 1C.
Although useful to illustrate a principle, electrical contact encoders are seldom used in today""s industrial applications due to numerous performance-related problems. These types of encoders have a finite life due to mechanical wear between the contact plates and brushes or pins. Reliability of a contact device is affected by possible contamination and corrosion which could isolate a contact area. Design and construction require extremely tight tolerances to prevent ambiguous states as discussed below. Some materials used in construction of a contact encoder can generate piezoelectric noise under shock or vibration.
Further, encoders such as illustrated on FIGS. 1A and 2A can generate invalid codes resulting from ambiguous states when an unwanted contact is made or is not made relative to another contact. For example, the end of a conductive plate, whether rotary or linear, is often a site of premature mechanical wear. This wear generates imprecise contact. Moreover, rotary encoder devices such as illustrated in FIG. 2A are particularly prone to this problem with ambiguous states. FIG. 2B shows an area 26 likely to be affected by ambiguous states resulting from an ambiguous contact position. The problem is amplified in multi-turn shaft encoders deployed as geared disks in a hierarchical relationship, where the gears produce a cumulative error from the least significant digit to the most significant.
By examining an example of a conventional multi-turn encoder 27 depicted in FIG. 2C, the problem will become more apparent. The multi-turn encoder 27 has four encoder disks A through D, each comprising large gears 28A through 28D, and further comprising encoding patterns 21 analogous to those depicted on FIGS. 2A and 2B (encoding patterns not illustrated on FIG. 2C). Large gears 28A through 28D mesh with small gears 29A through 29D. The ratio between large gears 28A through 28D and small gears 29A through 29D is a function of desired multiplication (M). Since computers use binary code, it is generally preferable to user a binary number as the multiplier. Using an exemplary value of 16 (or 24) for M, each large gear 28A through 28D needs to have 16xc3x97N teeth, where N is the number of teeth on each small gear 29A through 29D. Using an exemplary value of 8 (or 23) for N, then each large gear 28A through 28D has 16xc3x978=128 teeth. Now, with a gear ratio of 16:1 it will be understood that second encoder disk B turns one revolution for each sixteen revolutions of the first encoder disk A, and so on. Thus fourth encoder disk D turns one revolution for each 4096 revolutions of the first encoder disk A. Giving each encoder disk A through D on FIG. 2C an encoding pattern identical to the encoding pattern 21 depicted on FIGS. 2A and 2B, each encoder disk A through D monitors for 16 steps 0 through F (as notated in hexadecimal). The total number of steps capable of being monitored by multi-turn encoder 27 on FIG. 2C is thus 4096xc3x9716=65,536 (or 216).
Rotary encoders incur ambiguous state errors primarily because, with reference to FIGS. 2A and 2B, the different contact pins 24 travel a significantly different distance around in one revolution of the disk. The difference in distance of travel is the difference in circumference of two paths around the disk. Further, the greatest difference is between least significant bit (LSB) and most significant bit (MSB). For example, if the radius of the MSB track in FIGS. 2A and 2B is 0.2xe2x80x3 from the center of the shaft, and the radius of the LSB track is 1xe2x80x3 from the center of the shaft, the difference in circumferential travel is a factor of over 5, meaning that the MSB is moving over five times slower than the LSB. Referring again to FIG. 2D, any movement of the encoder disk A will produce {fraction (1/4095)} of that movement in encoder disk D. If the cumulative error of the three sets of gears between the disk is greater than {fraction (1/4095)} (about 0.088 degrees) of one revolution of the input shaft then a whole bit error occurs at the most significant digit. This equates to a maximum tolerance of less than 0.029 degrees per gear. Such tight manufacturing tolerances are hard to maintain, and variances from tolerance tend to create ambiguous state errors.
As noted above, ambiguous state errors are also caused by ambiguous contacts (such as illustrated as item 29 on FIG. 2B). Turning to FIG. 2C, ambiguous contacts on encoder disk D will cause their own problems on disk D, and will further cause magnified errors on disks C, B and A because the output of encoder disk D has a weighted output of up to 4096 times that of the other disks C, B and A. An ambiguous state on any one disk A, B, C or D can cause a serious error in measurement. The magnification factor over more than one disk again compounds the problem.
It will be understood that Gray code is the most widely used encoding system in encoders of the current art. Other encoding schemes such as binary V-scan are also used in an attempt to compensate for errors such as ambiguous states, or hardware component failure. Binary V-scan (not illustrated) uses two contacts per bit except for the LSB (the LSB allows a valid zero state). These two contact areas for each bit are constructed in a leading and lagging pattern which form a V shape encoding pattern. Error detection is enabled by using one contact to verify the other contact in a progressing set.
Gray code is generally favored over binary V-scan because only one bit may change for each positional step (as illustrated in truth table 15 on FIG. 1A). This makes error detection much easier because if two or more bits change state from one step to the next, then an error is detected.
The foregoing has described the problem in the art of ambiguous states due to imprecise manufacturing or premature contact wear. In addition to this problem, there is the problem of ambiguous states caused by invalid zero state recognition. It will be understood that Gray and binary V-scan encoding, like all codes allowing a valid zero state, are subject to such errors. Referring to the conventional linear electrical contact encoder illustrated in FIG. 1A, it will be seen that if the LSB contact pin 14A fails to make contact with the first contact area at Step 1, then this step is decoded as zero, a full one step error. If the LSB contact pin 14A and the next significant bit contact pin 14B each fail to contact the first two contact areas, the first detectable state is at Step 4, which is actually an error in itself because it will be decoded as Step 7. The first three steps would be decoded as zero, which is a valid but erroneous position. The first valid correct detectable step may indeed not occur until Step 7. The next step (Step 8) is a valid decodable step because only one bit changed. The encoder output will remain at Step 8 until Step C (step 12) which will be decoded as an invalid step because more than one bit changed. The total error prior to detecting the error is then eleven steps. If this error occurred at a fourth digit with a weighted magnitude of 4096/step (as is possible on the multi-turn encoder 27 illustrated on FIG. 2C), the total number of decoding errors would be 4096xc3x9711=45,056.
By analogy to the foregoing example, the magnitude of zero state errors can now be appreciated. Should even a one bit error occur on the 2nd, 3rd or 4th disk B through D of the multi-turn encoder 27 of FIG. 2C, because the error will be multiplied by 16, 256 or 4096 respectively. It will be understood that any encoding method allowing zero as a valid state is subject to these errors.
The exemplary use of contact-type encoders in FIGS. 1A, 1B, 1C, 2A, 2B and 2C is not meant to suggest that the above-described problems in the art of ambiguity and reliance on allowing zero as a valid state are unique to such contact-type encoders. In fact, optical, magnetic and other non-contact encoders have an even greater problem with ambiguity and require even tighter tolerances to control. It is often assumed that optical encoders using Gray code are more reliable than contact encoders because errors caused by contact wear and associated component failure are obviated. This can be false security because the encoding is still vulnerable to a zero state error. Light sources (often times LEDs) and light sensors (often times photo transistors) are subject to failure. More importantly, these encoders use integrated circuits for interface with the sensors. The interface circuits are subject to failure where a single integrated circuit chip may cause multiple sensor inputs to remain at the zero state. Thus, in view of the foregoing discussion, it will be appreciated that a single component failure in optical, magnetic and other non-contact encoders can produce undetectable errors of substantial magnitude.
Moreover, optical encoders have their own problems with ambiguity. As noted above, optical encoders are often favored in the current art over contact encoders because optical encoders do not suffer from as many wear-related problems. A typical optical encoder of the current art uses one or more light sources sensed by photoelectric sensors. These encoders nonetheless still continue to use Gray code encoded on plates and disks. FIGS. 3A and 3B depict encoded patterns 31A and 31B respectively, where plates 30A and 30B are opaque and the encoded patterns 31A and 31B are windows or slots selectively allowing light to pass through plates 30A and 30B. Such selective sensor activation is illustrated in FIG. 3C, in which an array of light sources 35 typically selectively energizes light sensors 36 according to the Gray code encoded on the plates 30A and 30B. By analogy to FIGS. 1A and 2A, it will be seen that the encoded patterns of windows or slots 31A and 31B on FIGS. 3A and 3B correspond to the encoded patterns of contact areas 11 and 21 on FIGS. 1A and 2A respectively.
As noted above, however, conventional optical encoders are recognized to be actually more vulnerable to ambiguity problems than contact-type encoders, the absence of contact-related problems notwithstanding For example, it is more difficult to control an optical (or other non-contact) communication path between source and sensor than on a contact-type encoder. Lenses of the light sources and sensors are also subject to moisture and other contamination. Such contamination may cause light to deflect, diffuse and diffract. This may not cause a problem when the encoder window can be manufactured to be in exact alignment with the desired sensory path, but may, as shown on FIG. 3D, cause ambiguous bit errors when the window is just a small amount out of alignment. This condition can often occur on the inner track of a rotary disk such as is illustrated on FIG. 3B, in view the smaller circumference and attendant smaller window size tolerances.
Further, when installed on cumulative gears, conventional optical encoders are also prone to the same error magnification problems described above with reference to FIG. 2C. In fact, optical (or other non-contact) encoders often require even tighter tolerances or the use of stepper type gearing, which severely limits effective operational input shaft speed.
From the previous discussion, it should now be appreciated that rotary optical encoders of the current art require much tighter manufacturing tolerances than their counterpart contact encoders. The problem is exacerbated when physical space limitations require the encoder assembly to be small. Size can be reduced in current art optical encoders by using, as shown on FIG. 3E, a disk or plate 37 providing a reflective encoded pattern. The light sources 35 and sensors 36 may then be deployed on the same side of the disk in order to reduce the size of the assembly. Now even tighter tolerances are required to prevent ambiguous states. As illustrated on FIG. 3F, some current art encoders use a disk or plate 38 providing a combination of encoded windows and reflective surfaces 39 to deflect the angle of the beam of light passing from the sources 35 to the sensors 36. These types of assemblies require yet even tighter tolerances due to the critical alignment of all components.
There is therefore a need in the art for an innovative encoding system which does not require such tight manufacturing tolerances to be reliable and accurate. Maintaining reliability and encoding accuracy while relaxing these tolerances will promote simplicity, robustness and lower cost. Further, if requirements for these tight tolerances are reduced, then source to sensor communications media other than light may be used. Source to sensor communications media having less precise radiation patterns, such as magnetic flux, radio waves, microwaves or ultrasound become serviceable. These alternative communications media may bring specific additional advantages to particular encoder applications or environments.
There is also a need in the art for an innovative encoding method which is not so sensitive to the adverse effects of error magnification in step-up gears. Such a new encoding system would be particularly advantageous by providing reliable and accurate scaling without limiting input shaft speed.
There is a further need in the art for an encoding system that tends to eliminate zero state errors. These types of errors are inherent in the physical susceptibility of hardware to breakdowns. Sources and sensors, and perhaps more importantly interface circuits, have a finite operational lifetime. An encoding system that at least recognizes an erroneous state (rather than erroneously misinterpreting it as an inaccurate valid state) will bring advantage to the encoding art.
These and other needs in the art are addressed by an inventive encoding system that expects, accepts and interprets both normal and abnormal states of a sensor array, and that further recognizes a zero state as a malfunction. The system is xe2x80x9cabsolute,xe2x80x9d in that it allows detection of the best fit detectable position of a movable object with an accuracy equal to the resolution which is equal to one-half the physical displacement of sensors or sources in an array. Such absolute references may be used to define a position detector which properly detects the position of an object after power is applied, even though the object may have moved further after power is removed. As a result, the inventive encoder does not require a battery back-up to detect position accurately after a power failure. This functionality is highly advantageous when detecting shaft position of a multi-turn shaft. The inventive encoding system is also scalable so that there are few limitations in deployment. Truth table logic is employed in a logic function that is designed to implement the foregoing attributes of the inventive encoding system.
It will be noted that embodiments of the invention as set forth below refer from time to time to sensors (or other types of elements capable of being detected in one of two different states) as being in either a xe2x80x9chighxe2x80x9d or xe2x80x9clowxe2x80x9d condition. It will be understood that, consistent with the principles of digital logic, that xe2x80x9chighxe2x80x9d refers to an activated state, and that xe2x80x9clowxe2x80x9d refers to a deactivated state.
According to one aspect, the inventive encoding system may be embodied in a method for encoding a current state of an array of elements, each element currently in either a high or low condition, the method comprising identifying a set of expected valid normal detected states of the array, the set of expected valid normal detected states excluding a state in which all elements are detected to be in low condition; identifying a set of expected valid abnormal detected states for the array, the set of expected valid abnormal detected states also excluding a state in which all elements are detected to be in low condition; identifying a set of events to which normal and abnormal detected states of the array are to correspond; developing a truth table in which each event in the set thereof corresponds to at least one expected valid normal detected state of the array and at least one expected valid abnormal detected state of the array; polling the current state of the array; and identifying a current event from the set of events based upon the truth table in view of current state of the array as polled.
According to another aspect, the inventive encoding system may be embodied in a method for encoding a positional state of a hierarchical gear assembly, the gear assembly comprising a plurality of interrelated rotary gears, one complete revolution of a lower gear causing a predetermined amount of rotation less than one revolution in an immediately higher gear, the method comprising deploying at least one source on each rotary gear; deploying a sensor array for each rotary gear, each array comprising at least three sensors in sensory communication with the sources on its corresponding rotary gear; identifying a set of expected valid normal detected states for each array; identifying a set of expected valid abnormal detected states for each array; identifying a set of positional states of the hierarchical gear assembly to which combinations of normal and abnormal detected states in each array are to correspond; developing a truth table in which each positional state of the hierarchical gear assembly in the set thereof corresponds to a combination of at least one expected valid normal detected state of each array and at least one expected valid abnormal detected state of each array; polling the current state of each array; and identifying a current positional state for the hierarchical gear assembly from the truth table based upon the combined current states of the arrays as polled.
It will therefore be seen that a technical advantage of the SCALF code invention is that it facilitates sensor array encoding in an environment in which both normal and abnormal states may be interpreted (such as is disclosed and described in co-pending application APD interpreting Abnormal States, referred to above). The inventive SCALF code will be seen to be a novel approach to such encoding that brings about certain further zero-state error detection advantages described below. It will be understood, however, that SCALF code has encoding applications in many embodiments beyond APD interpreting Abnormal States. In fact, SCALF code may be used to encode the condition of any array in which both normal and abnormal states are expected.
A further technical advantage of the SCALF code invention is its ability to minimize errors misinterpreting zero states in the array. By requiring that at least one sensor be activated at all times, encoding of the array according to SCALF code allows hardware to perform Boolean logic simplification in which a zero state output code has meaning as valid normal or abnormal state. SCALF code thus may interpret a zero state in the array as a fault condition.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

Scalable code absolute logic function (SCALF) encoder


A motorcycle tire which comprises a carcass (6) extending between tire bead portions (4), and a belt (7) disposed radially outside the carcass, wherein the belt (7) is formed by spirally winding at least two reinforcing members (11 and 12) having different elastic moduli so that the lower elastic modulus reinforcing member (11) and the higher elastic modulus reinforcing member (12) serially appear in the widthwise direction of the belt.

Recently, in order to improve tire performance during high speed running, spiral belts are widely used in radial tires, especially four-wheeled vehicle tires, e.g. passenger car tires.
In a motorcycle tire, the tread and carcass have curved profiles with a relatively small radius of curvature in comparison with four-wheeled vehicle tires. Therefore, a belt to be disposed between the tread and carcass must have a curved profile with a small radius of curvature.
To make a spiral belt for such motorcycle tire, a belt cord must be spirally wound on a curved face which is generally the radially outer surface of the carcass. Therefore, the windings are liable to be dislocated.
On the other hand, in order to obtain a desired belt effect, the cord count is varied. If spaces are provided between the windings to adjust the cord count, the windings are easily dislocated and loosened. Thus, the cord winding operation is very difficult. Even if such dislocation and looseness could be avoided, the cord spacings are liable to be disturbed during the tire building operation, and accuracy can not be achieved, and thereby high speed performance can not improved.
In the conventional spiral belts, therefore, to avoid such problems, a belt cord (a) is wound compactly, that is, without cord spacings as shown in FIG. 8. In this case, the cord count is determined by only the cord diameter. Therefore, to adjust belt characteristics, the material, denier, twist and/or structure of the belt cord itself have to be changed. As a result, the adjustable range and the design freedom are restricted.

Motorcycle tire with spirally wound belt


The present invention provides various simple and easy ways for each end user to manage the thread in a way that suits them. In some cases, the user experience requires only a single click. Additional embodiments allow user to manage inbox space, recover suppressed threads, be alerted on contextual changes of such threads, and so forth. The system allows the user to specifically configure his/her own email thread management scheme by selecting an email and choosing “Suppress Thread” on his/her user interface. The system then performs a number of steps such as examining the <message-id> and <references> headers of the selected email to configure the suppress filter. Once configured, the system will examine each email as it is received and examine its <message-id> and <references> headers per RFC 822. If the headers match the configured <messageid> and <responses> headers, the emails will be suppressed in the manner chosen by the user such as deletion or move to folder.

Emails are used not only for person to person communication but also to communicate questions, information and discussions to a large group of people. When people send emails to large lists of recipients through cooperative groups (e.g., LDAP groups), mailing lists or custom list of people, they often use "Reply to All" functionality so that no one is inadvertently dropped from the email thread. Use of "Reply to All" will forward the email created to everyone who was a recipient of the replied to email (i.e., everyone listed in the "To", "CC", and "BCC" address fields) including the original sender.
As a matter of background, a thread in computer science is short for a thread of execution. Threads are a way for a program to split itself into two or more simultaneously (or pseudo-simultaneously) running tasks. Multiple threads can be executed in parallel on many computer systems. An email thread or topic thread, however, is different. A topic thread (or simply "thread" when used in context) is a group of messages or postings to a newsgroup, mailing list, hypermail, blog or Internet forum, all relating to a single topic. An e-mail client or news client is said to have "threaded topics" if it groups messages on the same topic together for easy reading.
In FIG. 1, a basic Email System 101 is shown to illustrate this point. Email System 101 has Email Client 100, Email Server 102 and Email Clients 104 and Email Client 106. Of course, many more email clients could be connected through Email Server 102 and many more email servers interconnected within Network 108. Email Client 100 communicates with Email Client 104 and Email Client 106 through Email Server 102 and, in this example, in an email communication. Of course, the clients could be communicating via text messaging—TM—or instant messaging—IM. Alternatively, Email Client 100 and Email Clients 104, 106 may be connected directly for email communication in a "peer to peer" configuration. Email Server 102 is shown within a Network 108 which may be of the many various forms such as Internet, local area network (LAN), MAN, etc. Email Server 102 has an Interface (I/F) 114 and I/F 116 for interfacing with Email Clients 100, 104, 106 (and others). Email Server 102 further has an Email Mailbox/Processor 118 for processing and storing email communications between Email Client 100 and Email Clients 104, 106. This can be seen as Email Server 102 has Mailbox Components 110, 111, and 113.
Email Client 100 has an I/F 120 for interfacing with the Network 108 and Email Server 102. Likewise, Email Clients 104, 106 have interface components for interfacing with the Network 108 and Email Server 102. Email Client 100 has a Mailbox Component 110 for providing email communications 130 with Email Client 104 through the Network 108 and Email Server 102 and for storing received emails. Likewise, Email Clients 104, 106 each has a Mailbox Component 113, 111 for providing email communications 130 with Email Client 100 through the Network 108 and Email Server 102.
The Mailbox Components 110, 111 and 113 of Email Clients 100, 104, 106 correspond to the Mailbox Components of Email Server 102 and, for some applications, the Server Mail Components replicate to the Client Mail Components so that the Client Mail Components are local to the user. However, this is not germane to this invention. (Further information on this topic can be found at http://en.wikipedia.org/wiki/Replication_%28computer_science%29.)
In the course of an email "discussion", an Email Message 130 is sent to a number of parties such as Email Clients 104, 106. Email Client 104 "replies to all" with a Reply to All Message 132 so that it is sent to all of the initial recipients and the initial sender. This creates an email thread which is characterized by a common sender/recipient list. This, of course, can occur many times causing lots of activity at a user's mailbox.
In some cases this is desired, however, often a large part of the audience will find that particular parts of the conversation aren't relevant to them. Those people will find their email in-boxes cluttered with messages they don't want to receive, requiring that they waste time and energy manually disposing of the unwanted messages. Requesting participants not to use "Reply to All" adds more noise and confusion, with the likely prospect that people who are interested in the conversation will be dropped inadvertently.
The present invention, unlike the present state of the art, provides various simple and easy ways for each end user to manage the thread in a way that suits them. In some cases, the user experience requires only a single click.
One way, in the present state of the art, of handling unwanted email is spam filtering. (One could argue that any unwanted email in a user's inbox is spam.) However, spam filters are not flexible enough to remove unwanted mail in a thread without losing important information as spam filters are not aware of the particular structures and contexts of message threads.
An Active Filtering proxy filters electronic junk mail (also known as spam, bulk mail, or advertising) received at a Message Transfer Agent from remote Internet hosts using the Simple Mail Transfer Protocol (SMTP). The proxy actively probes remote hosts that attempt to send mail to the protected mail server in order to identify dial up PCs, open relays, and forged email. The system provides multiple layers of defense including: connect-time filtering based on IP address, identification of dial-up PCs attempting to send mail, testing for permissive (open) relays, testing for validity of the sender's address, and message header filtering. A sender's message must successfully pass through all relevant layers, or it is rejected and logged. Subsequent filters feed IP addresses back to the IP filtering mechanism, so subsequent mail from the same host can be easily blocked.
Since this technology identifies and restricts email by types and instances of sources, there is no good methodology to correctly filter only unwanted threads.
The most obvious alternative to the proposed invention is to use "Mail Rules" provided by most streamlined email Clients. One disadvantage is that mail rule creation requires an understanding of an advanced and often complex user interface. It is also a very manual process requiring specification of a number of conditions, not a one button feature.
For instance, the user could create a mail rule such as "IF SUBJECT CONTAINS xxxoldsubjecttextherexxx DELETE EMAIL". As this functionality depends on the email subject words in the Subject field, it doesn't resolve all the cases. Users can easily change the email subject to make it unrecognizable or emails with similar subjects might get deleted depending on the subject of the email thread.
In another case, the user could create a mail rule including the message-id and references field on the MIME header. Even though this might result in the desired functionality, it would be very hard for even experienced and advanced email users to master. This also requires the email client software to provide a user interface to such fields so that the user can program complex mail rules. However, email rules have to make assumptions about the subject or the sender while in real life email threads may have a subject line altered and an email sender may be a person shadowed by a group of recipients.
As shown at http://my.opera.com/community/tips/filterguide/index3.dml, an Active Thread is automatically generated by Opera Mail when a user receives a reply from someone to a message the user has sent. This may happen during the current session or at the next startup. The original sent message and replies will be grouped into an access point. This usually works better than filtering messages with the same subject line because Active Threads recognize the right messages even if the subject line has been completely changed. E-mail belonging to an Active Thread is characterized by the Message-ID and References header. A filter can't be made having the same functionality, since Message-ID's are unique and unpredictable. The Opera email client does not provide the functionality of the present invention.
IBM's Lotus® Notes® Release 7 has a function for filtering new mail using rules, but the functionality does not achieve the flexibility of this invention. In the present Lotus Notes Release 7 ("Notes"), a user can use mail rules to have Notes act automatically on new messages the user receives that meet certain conditions. For example, the user could create a rule that checks for messages from a certain sender or that contain a certain subject and have Notes automatically move the messages to a certain folder, send copies of the messages to someone, or delete unwanted messages before the user ever sees them in them Inbox.
Notes stores the mail rules the user creates in the Rules folder in the user's mail database. The user can go there to add new rules as well as work on the ones the user has created. For example, the user can edit rules, change their order so that one rule has priority over another, turn them off when the user doesn't want to use them, or delete them entirely.
This can be seen at FIG. 2 where the user interface of a mail client is shown at 200. First, the user needs to figure out that there even is a mail rules option then to find it under the "Tools" drop-down 206. Once that is figured out, "Rules" 202 may be selected causing a "New Rule" window 204 to appear. From there, the user needs to understand how to set a rule. More information can be found here: http://www-12.lotus.com/ldd/doc/domino_notes/Rnext/help6_client.nsf/b3266a3c17f9bb7085256b87 0069c0a9/66f679f4614e451385256c1c0037da0d?OpenDocument.
Newsgroups had somewhat similar functionality in newsgroup readers. Since postings on newgroups are associated at the source—such as discussions (where user posts reply to a specific thread generating the nesting structure deliberately)—it is much easier to control the user's views of discussion threads. Each user can go to a particular newsgroup and create a filter to subscribe/unsubscribe particular content to be downloaded. In contrast, a user of an email client gets unwanted content delivered to their inbox. Though the discussion features resemble the present invention to some extent, the present invention solves the problems particular to experiences in an email client, specifically receiving mail in an in-box rather than choosing which posted materials to visit in various repositories.
In view of the foregoing, a need exists to overcome these problems by providing a system and method for managing email threads, and, more particularly, to a system and method for easily allowing users to suppress or otherwise control specific aspects of email threads using a single click from the user's UI.

System and method for end-user management of E-mail threads using a single click

International Business Machines Corporation