An optical data storage medium comprises an optical medium with multiple data marks. Each data mark is arranged for modifying a portion of an optical reading beam incident thereon. At least one of the data marks is a delocalized data mark comprising a set of multiple diffractive elements collectively arranged for modifying a portion of the optical reading beam incident thereon. A method for recording data on an optical data storage medium comprises forming on or in the optical medium multiple data marks encoding the recorded data, including the at least one delocalized data mark. A method for reading an optical data storage medium comprises: successively illuminating with the optical reading beam the multiple data marks; sensing variations among the respective portions of the optical reading beam modified by the multiple data marks; and decoding from the sensed variations data encoded by the multiple data marks.

The field of the present disclosure relates to optical encoding of data. In particular, distributed diffractive structures (i.e. sets of diffractive elements) are formed in or on an optical medium for encoding the data.
Optical recording media in the form of compact disks (CDs), digital versatile discs or digital video discs (DVDs), and more advanced format optical discs play an important role in the distribution of software, data, music, video, or other content. Such discs typically include a data layer wherein localized micron- or sub-micron-scale marks (typically recessed pits, raised bumps, index or density variations, or other suitable marks) are optically or mechanically written, which is overlaid with a substantially transparent protective layer. Upon readout, a reading laser beam is typically focused through the transparent layer to a spot of a size similar to the size of the data marks when it reaches the data layer, and a portion of the reading beam is redirected by the data mark (usually back-reflected). Upon entering the transparent protective layer, the reading laser spot size is typically substantially larger, i.e. many times the size of data marks of the data layer (tens or hundreds of microns or more). The larger size of the reading laser spot as it enters the transparent protective layer reduces the effect of dust, scratches, nicks, or other imperfections or irregularities on the exterior surface of the disc. The light back-reflected from the data layer is detected and monitored for variations as the disk spins and the focused reading laser spot sweeps across the data marks and areas of the disc between the data marks. Variations in the detected, back-reflected optical signal arise from differences between the back-reflected reading laser beam reflected from the data marks and from areas between the data marks. Such differences may be differences of back-reflected power or intensity, back-reflected beam size or geometry, or other selected property of the back-reflected beam.
An exemplary geometry of a single data layer 100 and its protective transparent overcoat layer 102 are shown in FIG. 1. The optical disk may be multi-sided or have a more complex configuration, but for convenience of exposition only, only a single data layer and its protective transparent coating are described. The methods and devices disclosed herein may be implemented to single-layer or multi-layer or other advanced format optical discs provided they have surficial or interfacial regions surrounding the data layer through which read lasers may be transmitted. A data layer may also be protected or overcoated on the back (i.e. from the non-read side) although such details are not of particular significance for the present disclosure. Localized data marks 101 may be produced as a part of a molding or stamping process used to make the disc, by spot-based laser writing, or other means. The localized data marks 101 may typically comprise indentations of some depth into the non-read side of transparent layer, which therefore appear as bumps from the read side of the disc. The data marks thus formed on the non-read side of the transparent layer may be overcoated on the non-read side with a high or partial reflective material. A reading-laser beam 103 is shown focused onto one of the data marks 101. Any other suitable arrangements or adaptations of the data marks, data layer, or transparent protective layer may be employed while implementing the structures, methods, arrangements, or adaptations disclosed or claimed herein. The particular detailed nature of typically-employed data marks does not limit application of the methods and devices disclosed or claimed herein.
The data marks 101 are shown as bumps (from the read side) in FIG. 1. A copy of the disc can be made via optical writing where a sufficiently powerful laser beam is used to make optical marks on the data layer of a suitably sensitized blank disc. Commercial content from stamped, molded, or otherwise produced disc may typically be reproduced via a suitable focused-spot laser writer. The present disclosure describes distributed (i.e. non-localized) encoding of data on an optical disc by means that may be difficult to reproduce via a focused-spot laser writer. Data encoded as described in the present disclosure may be introduced in the same production process that produces standard localized data marks on the data layer or by alternate means such as secondary stamping, embossing, printing, e-beam writing, laser pattern generation, and so forth.
Various embodiments, implementations, and adaptations of optical waveguides, diffractive element sets, or distributed diffractive structures are disclosed in:                Application Ser. No. 11/376,714 filed Mar. 14, 2006 in the names of Thomas W. Mossberg, Dmitri lazikov, and Christoph M. Greiner (now U.S. Pat. No. 7,349,599);        Application Ser. No. 11/371,339 filed Mar. 7, 2006 in the names of Dmitri lazikov, Christoph M. Greiner, and Thomas W. Mossberg (now U.S. Pat. No. 7,327,908 issued Feb. 5, 2008);        Application Ser. No. 11/361,407 filed Feb. 23, 2006 in the name of Thomas W. Mossberg (now U.S. Pat. No. 7,116,453 issued Oct. 3, 2006);        Application Ser. No. 11/334,039 filed Jan. 17, 2006 in the names of Thomas W. Mossberg, Christoph M. Greiner, and Dmitri lazikov;        Application Ser. No. 11/298,290 filed Dec. 9, 2005 in the names of Thomas W. Mossberg, Dmitri lazikov, and Christoph M. Greiner (now U.S. Pat. No. 7,330,614 issued Feb. 12, 2008);        Application Ser. No. 11/280,876 filed Nov. 15, 2005 in the names of Christoph M. Greiner, Dmitri lazikov, and Thomas W. Mossberg;        Application Ser. No. 11/239,540 filed Sep. 28, 2005 in the name of Thomas W. Mossberg (now U.S. Pat. No. 7,009,743 issued Mar. 7, 2006);        Application Ser. No. 11/213,345 filed Aug. 25, 2005 in the names of Christoph M. Greiner, Dmitri lazikov, and Thomas W. Mossberg (now U.S. Pat. No. 7,120,334 issued Oct. 10, 2006);        Application Ser. No. 11/210,439 filed Aug. 23, 2005 in the names of Dmitri lazikov, Christoph M. Greiner, and Thomas W. Mossberg (now U.S. Pat. No. 7,359,597 issued Apr. 15, 2008);        Application Ser. No. 11/155,327 filed Jun. 16, 2005 in the names of Christoph M. Greiner, Thomas W. Mossberg, and Dmitri lazikov (now U.S. Pat. No. 7,190,858 issued Mar. 13, 2007);        Application Ser. No. 11/076,251 filed Mar. 8, 2005 in the name of Thomas W. Mossberg (now U.S. Pat. No. 7,062,128 issued Jun. 13, 2006);        Application Ser. No. 11/062,109 filed Feb. 17, 2005 in the names of Christoph M. Greiner, Thomas W. Mossberg, and Dmitri lazikov (now U.S. Pat. No. 7,181,103 issued Feb. 20, 2007);        Application Ser. No. 11/055,559 filed Feb. 9, 2005 in the names of Christoph M. Greiner, Thomas W. Mossberg, and Dmitri lazikov (now U.S. Pat. No. 7,123,794 issued Oct. 17, 2006);        Application Ser. No. 11/021,549 filed Dec. 23, 2004 in the names of Dmitri lazikov, Christoph M. Greiner, and Thomas W. Mossberg (now U.S. Pat. No. 7,260,290 issued Aug. 21, 2007);        Application Ser. No. 10/998,185 filed Nov. 26, 2004 in the names of Dmitri lazikov, Christoph M. Greiner, and Thomas W. Mossberg (now U.S. Pat. No. 6,993,223 issued Jan. 31, 2006);        Application Ser. No. 10/989,244 filed Nov. 15, 2004 in the names of Christoph M. Greiner, Thomas W. Mossberg, and Dmitri lazikov (now U.S. Pat. No. 6,961,491 issued Nov. 1, 2005);        Application Ser. No. 10/989,236 filed Nov. 15, 2004 in the names of Christoph M. Greiner, Dmitri lazikov, and Thomas W. Mossberg (now U.S. Pat. No. 6,965,716 issued Nov. 15, 2005);        Application Ser. No. 10/923,455 filed Aug. 21, 2004 in the names of Thomas W. Mossberg, Dmitri lazikov, and Christoph M. Greiner (now U.S. Pat. No. 7,054,517 issued May 30, 2006);        Application Ser. No. 10/898,527 filed Jul. 22, 2004 in the named of Dmitri lazikov, Christoph M. Greiner, and Thomas W. Mossberg (now U.S. Pat. No. 7,194,164 issued Mar. 20, 2007);        Application Ser. No. 10/857,987 filed May 29, 2004 in the names of Lawrence D. Brice, Christoph M. Greiner, Thomas W. Mossberg, and Dmitri lazikov (now U.S. Pat. No. 6,990,276 issued Jan. 24, 2006);        Application Ser. No. 10/842,790 filed May 11, 2004 in the names of Thomas W. Mossberg, Christoph M. Greiner, and Dmitri lazikov (now U.S. Pat. No. 6,987,911 issued Jan. 17, 2006);        Application Ser. No. 10/798,089 filed Mar. 10, 2004 in the names of Christoph M. Greiner, Thomas W. Mossberg, and Dmitri lazikov (now U.S. Pat. No. 6,823,115 issued Nov. 23, 2004);        Application Ser. No. 10/794,634 filed Mar. 5, 2004 in the names of Dmitri lazikov, Thomas W. Mossberg, and Christoph M. Greiner (now U.S. Pat. No. 6,985,656 issued Jan. 10, 2006);        Application Ser. No. 10/740,194 filed Dec. 17, 2003 in the names of Dmitri lazikov, Thomas W. Mossberg, and Christoph M. Greiner (now U.S. Pat. No. 7,224,855 issued May 29, 2007);        Application Ser. No. 10/653,876 filed Sep. 2, 2003 in the names of Christoph M. Greiner, Dmitri lazikov, and Thomas W. Mossberg (now U.S. Pat. No. 6,829,417 issued Dec. 7, 2004);        Application Ser. No. 10/602,327 filed Jun. 23, 2003 in the name of Thomas W. Mossberg (now U.S. Pat. No. 6,859,318 issued Feb. 22, 2005);        Application Ser. No. 10/229,444 filed Aug. 27, 2002 in the names of Thomas W. Mossberg and Christoph M. Greiner (now U.S. Pat. No. 6,678,429 issued Jan. 13, 2004);        Application Ser. No. 09/843,597 filed Apr. 26, 2001 in the name of Thomas W. Mossberg (now U.S. Pat. No. 6,965,464 issued Nov. 15, 2005);        Application Ser. No. 09/811,081 filed Mar. 16, 2001 in the name of Thomas W. Mossberg (now U.S. Pat. No. 6,879,441 issued Apr. 12, 2005).
Application Ser. No. 11/376,714 is hereby incorporated by reference as if fully set forth herein. Application Ser. No. 11/376,714 and many of the other references listed above are indicative of the state of the art for forming diffractive elements. Some of these cited references describe diffractive elements formed in a one- or two-dimensional optical waveguide, wherein the input or output optical signal propagates in the waveguide. Some of these cited references describe diffractive elements forming surface gratings, wherein both input and output optical signals propagate as diffraction-guided optical beams. For one or more of the references cited hereinabove, it may be the case that the devices, structures, embodiments, implementations, adaptations, procedures, or techniques disclosed therein may be employed, within the scope of the present disclosure or appended claims, for optical encoding of data.

Optical encoding of data with distributed diffractive structures


An image forming apparatus may include a scanner configured to read a document, a feeder configured to feed a sheet, a printer configured to print an image on the sheet, a processor, and memory storing instructions. The instructions, when executed by the processor, may cause the image forming apparatus to control the scanner to read the document to generate read data, determine whether the read data provides an image while the scanner is reading the document, and control the feeder to start feeding the sheet to the printer in response to determining that the read data provides the image. Determining whether the read data provides the image may include determining whether a substantially blank sheet would be printed based on the read data.

1. Field of Art
The disclosure relates to an image forming apparatus having a copy function. More specifically, the disclosure relates to the image forming apparatus capable of performing a direct copying in which printing may be started without waiting for the completion of a sheet reading for one page.
2. Description of Related Art
Known copying techniques include a memory copying technique and a direct copying technique. In the memory copying technique, printing is started on the condition that read data of a sheet for one page has been stored in a memory. In the direct copying technique, printing is started without waiting for the completion of a sheet reading for one page. The memory copying technique may have an advantage in processing, e.g., multiple copy production, scaling changes, and multiple page arrangement per sheet. The direct copying technique may have an advantage to obtain a copy output earlier.
In the known direct copying techniques, printing is started without waiting for the completion of a sheet reading for one page, and therefore, when read data does not contain any effective image, a blank sheet is output even when such output is unnecessary.

Image forming apparatus that starts feeding sheet upon detecting an image


Methods and systems for evaluating the quality of a geospatial data set are provided. Regions of a data set may be selected for review based on statistical methods and a distribution of map features in the data set. Based on errors identified in the selected regions, one or more quality scores may be generated for the data set. Quality scores may be applied toward assessing the utility of the data set against an intended use. Quality scores may be modified in response to an indication that certain feature classes are not relevant for an intended use of the data set. Information associated with the review of a data set may be tracked and stored.

Geospatial data is typically generated by identifying features in images captured by aerial sensors, such as cameras in satellites, airplanes, helicopters, unmanned aerial system, or other aerial platforms. Photogrammetrists or spatial analysts typically view these images and identify desired features. A cartographer or photogrammetrist may identify a feature in an overhead image, such as a building, road, river, or lake, and create a corresponding feature in a geospatial data set, which may be used to produce a map. Geospatial data sets are often generated using a software based tool. Several types of errors may arise when geospatial data is generated. For example, features in an image may be overlooked and are not placed in the geospatial data set (omission), or features may be erroneously included in the data set when no such feature exists in the real world (commission). Additionally, features placed in the geospatial data set may be subject to other types of error. A feature may be properly identified but placed at the wrong location in the geospatial data set (positional accuracy), or a feature may be properly identified and placed in the geospatial data set, but may be characterized incorrectly. For example, a feature may be characterized based on an incorrect theme (e.g. a road is incorrectly characterized as a river), or a feature may be characterized as having an incorrect attribute (e.g. a feature may be properly identified as a building, but the mapmaker may incorrectly classify the building as a school instead of a church).
The quality of a geospatial data set—that is, the quantity and type of errors in the data set—is typically important to map makers and map consumers. However, currently no method exists for accurately and objectively characterizing the quality of a geospatial data set.

Methods and systems for assessing the quality of geospatial data


A high quality voice transformation system and method operates during a training mode to store voice signal characteristics representing target and source voices. Thereafter, during a real time transformation mode, a signal representing source speech is segmented into overlapping segments, analyzed to separate the excitation spectrum from the tone quality spectrum. A stored target tone quality spectrum is substituted for the source spectrum and then convolved with the actual source speech excitation spectrum to produce a transformed speech signal having the word and excitation content of the source, but the acoustical characteristics of a target speaker. The system may be used to enable a talking, costumed character, or in other applications where a source speaker wishes to imitate the voice characteristics of a different, target speaker.

In 1928 Mickey Mouse was introduced to the public in the first "talking" animation film entitled, "Steamboat Willy". Walt Disney, who created Mickey Mouse, was also the voice of Mickey Mouse. Consequently, when Walt Disney died in 1966 the world lost a creative genius and Mickey Mouse lost his voice.
It is not unusual to discover during the editing of a dramatic production that one or more scenes are artistically flawed. Minor background problems can sometimes be corrected by altering the scene images. However, if the problem lies with the performance itself or there is a major visual problem, a scene must be done over. Not only is this expensive, but occasionally an actor in the scene will no longer be available to redo the scene. The editor must then either accept the artistically flawed scene or make major changes in the production to circumvent the flawed scene.
A double could typically be used to visually replace a missing actor in a scene that is being redone. However, it is extremely difficult to convincingly imitate the voice of a missing actor.
A need thus exists for a high quality voice transformation system that can convincingly transform the voice of any given source speaker to the voice of a target speaker. In addition to its use for motion picture and television productions, a voice transformation system would have great entertainment value. People of all ages could take great delight in having their voices transformed to those of characters such as Mickey Mouse or Donald Duck or even to the voice of their favorite actress or actor. Alternatively, an actor dressed in the costume of a character and imitating a character could be even more entertaining if he or she could speak the voice of the character.
A great deal of research has been conducted in the field of voice transformation and related fields. Much of the research has been directed to transformation of source voices to a standardized target voice that can be more easily recognized by computerized voice recognition systems.
A more general speech transformation system is suggested by an article by Masanobu Abe, Satoshi Nakamura, Kiyohiro Shikano and Hisao Kuwabara, "Voice Conversion Through Vector Quantization," IEEE International Conference on Acoustics, Speech and Signal Processing, (April 1988), pp. 655-658. While the disclosed method produced a voice transformation, the transformed target voice was less than ideal. It contained a considerable amount of distortion and was recognizable as the target voice less than 2/3 of the time in an experimental evaluation.


A process for introducing annular coated catalysts K into a reaction tube of a tube bundle reactor, in which adhering pairs of annular coated catalysts K formed in the preparation of the annular coated catalysts K, before the introduction thereof into the reaction tube, are removed at least partly from the annular coated catalysts K.

The present invention relates to a process for introducing a portion withdrawn from at least one production charge of annular coated catalysts K into a reaction tube of a tube bundle reactor for the purpose of charging this reaction tube with a fixed catalyst bed suitable for performing a heterogeneously catalyzed partial gas phase oxidation of an organic starting compound.
Processes for heterogeneously catalyzed partial gas phase oxidation of organic starting compounds in fixed catalyst beds disposed in the reaction tubes of tube bundle reactors are known for the preparation of numerous industrial chemicals.
Examples of such heterogeneously catalyzed partial gas phase oxidations of organic compounds include the conversion of methanol to formaldehyde (cf., for example, CH-A 449 600 and CH-A 38 828), the conversion of propene to acrolein and/or acrylic acid (cf., for example, DE-A 23 51 151), the conversion of tert-butanol, isobutene, isobutane, isobutyraldehyde or the methyl ether of tert-butanol to methacrolein and/or methacrylic acid (cf., for example, DE-A 25 26 238, EP-A 092 097, EP-A 058 927, DE-A 41 32 263, DE-A 41 32 684 and DE-A 40 22 212), the conversion of acrolein to acrylic acid and of methacrolein to methacrylic acid (cf., for example, DE-A 25 26 238), the conversion of o-xylene and/or naphthalene to phthalic anhydride (cf., for example, EP-A 522 871) and the conversion of butadiene to maleic anhydride (cf., for example, DE-A 21 06 796 and DE-A 16 24 921), the conversion of C4 hydrocarbons such as 1-butene, 2-butene, butadiene and/or n-butane to maleic anhydride (cf., for example, GB-A 14 64 198 and GB-A 12 91 354), the conversion of indanes to anthraquinones (cf., for example, DE-A 20 25 430), the conversion of ethylene to ethylene oxide (cf., for example, EP-A 352 849, EP-A 352 850, EP-A 532 325, U.S. Pat. Nos. 5,155,242 and 5,262,551) or of propylene to propylene oxide (cf., for example, DE-B 12 54 137, DE-A 21 59 346, EP-A 372 972, WO 89/07101, DE-A 43 11 608), the conversion of propylene and/or acrolein to acrylonitrile (cf., for example, DE-A 23 51 151), the conversion of isobutene and/or methacrolein to methacrylonitrile (i.e. the term "partial oxidation" shall, in this document, also comprise partial ammoxidation, i.e. a partial oxidation in the presence of ammonia), the oxidative dehydrogenation of hydrocarbons or hydrocarbon derivatives (cf., for example, DE-A 23 51 151), the conversion of propane to acrylonitrile or to acrolein and/or acrylic acid (cf., for example, DE-A 101 31 297, EP-A 10 90 684, EP-A 608 838, DE-A 100 46 672, EP-A 529 853, WO 01/96270 and DE-A 100 28 582) etc.
While a full oxidation of an organic compound with molecular oxygen is understood in this document to mean that the organic compound is converted under the reactive action of molecular oxygen such that all of the carbon present in the organic compound is converted to oxides of carbon and all of the hydrogen present in the organic compounds to oxides of hydrogen, all different exothermic conversions of an organic compound under the reactive action of molecular oxygen are summarized in this document as partial oxidations of an organic compound.
In particular, in this document, partial oxidations shall be understood to mean those exothermic conversions of organic compounds under the reactive action of molecular oxygen in which the organic compound to be oxidized partially, after the conversion has ended, comprises at least one oxygen atom more in chemically bound form than before the partial oxidation was performed.
A tube bundle reactor is normally an apparatus which comprises a vertically arranged bundle of reaction tubes which is surrounded by a reactor jacket, both ends of the individual reaction tubes being open and the upper end of each reaction tube ending sealed into a passage orifice of an upper tube plate sealed at the top into the reactor jacket and the lower end ending sealed into a passage orifice of a lower tube plate sealed at the bottom into the reactor jacket, the exterior of the reaction tubes, the upper and the lower tube plate and the reactor jacket together delimiting the reaction tube surrounding space, and each of the two tube plates being spanned by a reactor hood having at least one orifice. In the performance of a heterogeneously catalyzed partial gas phase oxidation in such a tube bundle reactor, its reaction tubes are charged with a fixed catalyst bed (a fixed catalyst bed is introduced into its reaction tubes; a fixed catalyst bed is disposed in its reaction tubes) and a reaction gas input mixture which comprises the organic compound (organic starting compound) to be oxidized partially and molecular oxygen is fed in through the at least one orifice in one of the two reactor hoods, and the product gas mixture which comprises the target product which results through partial gas phase oxidation of the organic starting compound to be oxidized partially to the desired target product as it flows through the fixed catalyst bed disposed in the reaction tubes is removed via the at least one orifice of the other reactor hood, while at least one (generally liquid) heat exchange medium is conducted around the reaction tubes on the jacket side of the tube bundle reactor. Normally, in the case of use of at least one liquid heat exchange medium, it is conducted around the reaction tubes such that each of the two surfaces of the two tube plates facing one another is wetted by liquid heat exchange medium. The at least one (for example liquid) heat exchange medium is typically conducted into the reaction tube surrounding space with a temperature THin and back out of the reaction tube surrounding space with the temperature of THout.
The statement that the reaction tubes are sealed into the passage orifices in the upper and lower tube plate means that there is no means of passage for the heat exchange medium between the reaction tube outer wall and the bore wall (i.e. wall of the passage orifice or else shell of the passage orifice). Such a seal can be effected, for example, as described in DE-20 2006 014 116 U1.
In principle, the at least one heat exchange medium may also be conducted in gaseous form or in the boiling state through the reaction tube surrounding space. Examples of such tube bundle reactors and heterogeneously catalyzed partial gas phase oxidations performed therein are disclosed, for example, by EP-A 700 893, DE-A 44 31 949, WO 03/057 653, EP-A 16 95 954, WO 03/055 835, WO 03/059 857, WO 03/076 373, DE 699 15 952 T2, DE-A 10 2004 018 267, DE 20 2006 014 116 U1 and DE 10 2007 019 597.6, and also the prior art cited in the aforementioned documents.
In general, the components of the tube bundle reactor are manufactured from steel. Useful manufacturing steel is both stainless steel (for example of DIN materials number 1.4541 or 1.4571) and black steel or ferritic steel (for example DIN materials 1.0481, 1.0315 or material 1.0425). Frequently, all components of the tube bundle reactor are manufactured from the same steel type. In many cases, the reactor hoods are manufactured from ferritic steel and plated on their inner side with stainless steel. In some cases, the reactor jacket is also manufactured from a different steel type from the remaining part of the tube bundle reactor, since rolled steel can be used for its production.
In this document, the reaction tube surrounding space is defined as the space delimited by the exterior of the reaction tubes, the two tube plates and the reactor jackets together, within which the at least one (generally liquid) heat exchange medium is conducted. In the simplest manner, in the reaction tube surrounding space, only one (preferably liquid) heat exchange medium is conducted (such a procedure is also referred to as a one-zone method in the one-zone tube bundle reactor). It is typically fed to the reaction tube surrounding space at its upper or at its lower end with its entrance temperature THin through orifices in the reactor jacket, and conducted back out of the reaction tube surrounding space at the opposite end with an exit temperature of THout through orifices in the reactor jacket.
As a result of the exothermicity of the gas phase partial oxidations, during the performance of a heterogeneously catalyzed partial gas phase oxidation, THout≧THin (equality relates to the case of evaporative cooling). With the aid of a heat exchanger, heat is typically withdrawn from a portion or the entirety of the (preferably liquid) heat exchange medium conducted out of the reaction tube surrounding space before it is fed back to the reaction tube surrounding space with the temperature THin.
In the reaction tube surrounding space, the (preferably liquid) heat exchange medium can in principle be conducted around the reaction tubes in simple co- or countercurrent to the reaction gas mixture flowing within the reaction tubes. However, it can also be conducted around the reaction tubes in a meandering manner with the aid of corresponding deflecting plates, such that only over the entire reaction tube surrounding space does a cocurrent or countercurrent to the flow direction of the reaction gas mixture in the reaction tubes exist. When the heat exchange medium used is liquid under the use conditions, it should, appropriately from an application point of view, have a melting point in the range from 0 (or from 50) to 250° C., preferably from 120 to 200° C.
Useful such liquid heat exchange media include, for example, melts of salts such as potassium nitrate, potassium nitrite, sodium nitrite and/or sodium nitrate, and also melts of metals such as potassium, sodium, mercury and alloys of different metals. However, it is also possible to use ionic liquids (in which at least one of the oppositely charged ions comprises at least one carbon atom) or heat carrier oils (e.g. high-boiling organic solvents such as mixtures of Diphyl® and dimethyl phthalate). Useful gaseous heat exchange media include, for example, steam under elevated pressure or else flue gases. Evaporative cooling can, for example, also be undertaken with boiling water under pressure.
To improve the selectivity of target product formation, the heterogeneously catalyzed partial gas phase oxidation of an organic compound can also be performed as a multizone method (for example two-zone method) in a multizone tube bundle reactor (for example in a two-zone tube bundle reactor). In this case, within the reaction tube surrounding space, (for example two), essentially spatially separate (preferably liquid) heat exchange media (which are normally of the same type) are conducted (these may, for example, be separated by separating tube plates which have corresponding passage orifices for the reaction tubes and are inserted into the reaction tube surrounding space).
The reaction tube longitudinal section over which the particular (preferably liquid) heat exchange medium extends represents a temperature zone or reaction zone (the one-zone tube bundle reactor correspondingly has only one reaction zone).
Within the particular temperature zone, the (preferably liquid) heat exchange medium can be conducted as in the one-zone method (also relative to the flow direction of the reaction gas mixture). For the difference between THout and THin, the statements regarding the one-zone method apply in an essentially identical manner to the individual temperature zone.
A graphic distinction between a one-zone method and a two-zone method (between a one-zone tube bundle reactor and a two-zone tube bundle reactor) is shown schematically, for example, by the figures of DE 102007019597.6 and the figures of EP-A 1695954. Aside from these, multizone methods are described, for example, in documents EP-A 1734030, DE-A 10313214, DE-A 10313219, DE-A 10313211, DE-A 10313208 and in the prior art cited in these documents. They are advantageous in particular when a high loading of the fixed catalyst bed with the organic compound to be oxidized partially is selected. The loading of the fixed catalyst bed with reaction gas mixture or with one reaction gas mixture component is understood to mean the amount of reaction gas mixture or reaction gas mixture component in standard liters (I (STP); the volume that the corresponding amount would theoretically take up in gaseous form at 0° C. and 1 atm) which is conducted through one liter of fixed catalyst bed per hour (pure inert beds are not included).
The temperature THin of the at least one (preferably liquid) heat exchange medium in heterogeneously catalyzed partial gas phase oxidations of organic starting compounds is typically in the range from 200 to 500° C., frequently in the range from 250 to 400° C. and in many cases in the range from 250 to 310° C.
The working pressure in a heterogeneously catalyzed partial gas phase oxidation may be either below standard pressure (for example up to 0.5 bar; the reaction gas mixture is sucked through) or above standard pressure. Typically, the aforementioned working pressure will be at values of from 1 to 5 bar, frequently from 1.5 to 3.5 bar (in each case absolute). Normally, the working pressure in a heterogeneously catalyzed partial gas phase oxidation of an organic starting compound will not exceed 100 bar.
The reaction gas input mixture (or else reaction gas entry mixture) itself may, in the different procedures in the tube bundle reactor, be conducted either from the top downward or from the bottom upward in the reaction tubes (i.e. the at least one feed orifice may be disposed either in the upper reactor hood or in the lower reactor hood). The same applies to the conduction of the (preferably liquid) heat exchange medium.
The reaction gas input mixture may, on entry into the reaction tubes, in principle be preheated to the temperature of the heat exchange medium flowing on the corresponding tube plate underside.
The temperature of the reaction gas entry mixture, on entry into the reaction tubes, may, though, also be below this temperature of the heat exchange medium. This is advisable when the reaction tubes, in flow direction of the reaction gas mixture, are charged first with a longitudinal section of shaped bodies inert to the partial oxidation, before the catalytically active section of the fixed catalyst bed comprising shaped bodies having catalytically active composition begins. In the course of flow through this inert section, the reaction gas entry mixture may then be heated to the temperature of the heat exchange medium which flows around the corresponding catalytically active reaction tube section. In principle, the reaction gas entry mixture (the product gas mixture) can also be fed in (removed) via more than one feed orifice (removal orifice) present in the corresponding reactor hood. In general, though, both the feed of the reaction gas entry mixture and the removal of the product gas mixture are each effected via only one orifice in the corresponding reactor hood.
Frequently, a heterogeneously catalyzed partial gas phase oxidation of an organic compound can, in spatial terms, be connected immediately downstream of a heterogeneously catalyzed partial gas phase oxidation of another organic compound (in this case, the target product of the preceding partial oxidation is normally the organic compounds to be oxidized partially in the downstream partial oxidation) or connected upstream of it. In particular, in these cases, the feeding or removing reactor hood can be reduced to a cylindrical tube orifice (designed as a cylindrical tube opening), which may, for example, form a cylindrical transition to an aftercooler (cf., for example, DE-A 10 2004 018267 and DE 102007019597.6).
It will be appreciated that it is also possible to perform two heterogeneously catalyzed partial gas phase oxidations which are two successive gas phase partial oxidation steps in immediate succession in the reaction tubes of a multizone tube bundle reactor (for example in a two-zone tube bundle reactor), in which case the charge of the fixed catalyst bed in the reaction tubes of the multizone tube bundle reactor normally changes in a corresponding manner at the transition from one reaction step to the next reaction step (cf., for example, the performance of multistage heterogeneously catalyzed partial gas phase oxidations in the so-called "single reactor" according to EP-A 1388533, U.S. Pat. No. 6,069,271, EP-A 990636, US-A 2006/0161019 and EP-A 1106598). Examples of the performance of such multistage heterogeneously catalyzed partial gas phase oxidations in the multizone tube bundle reactor (for example two-zone tube bundle reactor) are the heterogeneously catalyzed partial gas phase oxidation of propylene to acrylic acid and of isobutene to methacrylic acid.
In addition to molecular oxygen and the organic starting compounds to be oxidized partially as reactants, the reaction gas input mixture of a heterogeneously catalyzed partial gas phase oxidation generally also comprises a diluent gas which behaves essentially inertly under the conditions of the heterogeneously catalyzed gas phase partial oxidation. In this document, this is understood to mean those diluent gases whose constituents, present in the reaction gas mixture, under the conditions of the heterogeneously catalyzed partial gas phase oxidation—each constituent taken alone—remain unchanged to an extent of more than 95 mol %, preferably to an extent of more than 99 mol %. They have the task firstly of absorbing some of the heat of reaction and conducting it out of the tube bundle reactor as a constituent of the product gas mixture, and secondly of ensuring that the reaction gas mixture is generally outside the explosion range. Inert diluent gases typically suitable for heterogeneously catalyzed partial gas phase oxidations of organic starting compounds are, for example, N2, CO2, steam, noble gases and in many cases also saturated hydrocarbons (for example in a partial oxidation of unsaturated organic compounds) or mixtures of all or of some of the aforementioned possible inert diluent gases.
The reactants present in the reaction gas mixture of a heterogeneously catalyzed partial gas phase oxidation (O2 and the organic starting compound) are converted as the reaction gas mixture passes through the fixed catalyst bed disposed in the reaction tubes during the residence time of the reactants over the catalyst surface.
The reaction tubes in the tube bundle reactor are, as already mentioned, generally manufactured from ferritic steel or from stainless steel and frequently have a wall thickness of a few mm, for example from 1 to 3 mm. Their internal diameter is usually a few cm, for example from 10 to 50 mm, frequently from 15 to 30 mm, or from 20 to 30 mm. The tube length extends normally to a few meters (a typical reaction tube length is in the range from 1 to 10 m, frequently from 2 to 8 m or from 2 to 6 m, in many cases from 2 to 4 m).
Appropriately from an application point of view, the number of reaction tubes accommodated in the tube bundle reactor is at least 1000, frequently at least 3000 or 5000 and in many cases at least 10 000. Frequently, the number of reaction tubes accommodated in the tube bundle reactor is from 15 000 to 30 000, or to 40 000, or to 50 000. Tube bundle reactors having a number of reaction tubes above 50 000 are usually the exception. Within the reaction tube surrounding space, the reaction tubes are normally arranged in essentially homogeneous distribution, the distribution appropriately being selected such that the distance of the central internal axes of mutually adjacent reaction tubes (the so-called reaction tube pitch) is from 25 to 55 mm, frequently from 35 to 55 mm.
Especially in the case of tube bundle reactors with a relatively large cross section of their tube plates, it is appropriate from an application point of view to leave a region without tubes in the center of the tube bundle reactor, and instead to support the upper tube plate within this region.
In principle, the total number of reaction tubes is distinguished into working tubes (the overwhelming majority of the reaction tubes) and into thermal tubes. While the working tubes are those reaction tubes in which the heterogeneously catalyzed partial gas phase oxidation in the actual sense is performed, thermal tubes primarily serve the purpose of monitoring and controlling the reaction temperature as a representative of the other reaction tubes (the working tubes). For this purpose, the thermal tubes, in addition to the fixed catalyst bed, normally comprise a thermowell which is conducted along the center of the thermal tube and is charged merely with a temperature sensor (for example a multithermoelement or an axially movable single thermoelement) (this is in many cases, but not necessarily, compensated for by an elevated internal diameter of the thermal tubes compared to the working tubes). In general, the number of thermal tubes in a tube bundle reactor is very much smaller than the number of working tubes. Normally, the number of thermal tubes is ≦20. In this context, it is of particular significance that the thermal tubes are charged with fixed catalyst bed such that the profile of the reaction temperature along the interior of a thermal tube corresponds very accurately to the profile of the reaction temperature along the interior of a working tube (cf. EP-A 873 783 and EP-A 1270 065).
The profile of the reaction temperature in the reaction tubes is determined firstly by the evolution of heat caused by the exothermicity of a heterogeneously catalyzed partial gas phase oxidation and secondly, inter alia, by the transfer of this heat of reaction to the at least one heat exchange medium conducted within the reaction tube surrounding space.
Since heterogeneously catalyzed partial gas phase oxidations are typically markedly exothermic reactions, and the heat of reaction is transferred to the at least one heat exchange medium at a finite rate, the temperature of the reaction gas mixture in the course of reactive passage thereof through the fixed catalyst bed is normally different from the temperature of the fluid heat exchange medium which flows around the fixed catalyst bed outside the reaction tubes. It is typically above the entrance temperature of the heat exchange medium THin into the corresponding reaction zone (temperature zone) and, along a reaction zone, generally passes through an absolute maximum (hotspot maximum) or falls proceeding from an absolute maximum value (if appropriate via further relative maxima). These maximum values of the reaction temperature (of the temperature of the reaction gas mixture) are typically referred to as so-called "hotspot temperatures".
The hotspot temperature is therefore of particular significance because, where the reaction temperature in the reaction tube is elevated (the temperature of the fixed catalyst bed corresponds essentially to the temperature of the reaction gas mixture at the particular point), the irreversible aging processes in the fixed catalyst bed also proceed at an increased rate and cause accelerated deactivation of the fixed catalyst bed.
In this regard, it is known from the prior art that heterogeneously catalyzed partial gas phase oxidations in the reaction tubes of a tube bundle reactor which have been charged with a fixed catalyst bed can be performed over comparatively long periods (up to several years) in the case of careful operation without the fixed catalyst bed in the reaction tubes having to be renewed (freshly charged) (cf., for example, DE-A 10 350 822, DE-A 10 2004 025 445, EP-A 17 34 030 and the prior art acknowledged in these documents). The irreversible deactivation of the fixed catalyst bed is counteracted under otherwise essentially unchanged operating conditions typically by an increase in THin and/or an increase in the working pressure in the reaction tubes (cf., for example, EP-A 11 06 598, DE-A 10 351 269, EP-A 17 34 030, EP-A 990 636, DE-A 10 2004 025 445). These measures allow the target product space-time yield to be retained over prolonged operating times. However, they cause the aging process of the fixed catalyst bed to be accelerated further to an increasing extent (particular aging processes within the catalysts which contribute to aging proceed, for example, more rapidly). On attainment of a maximum value of THin, the fixed catalyst bed finally has to be exchanged completely (cf. also DE-A 10 232 748, EP-A 11 06 598 and DE-A 10 2007 010 422).
However, a disadvantage of such a complete exchange is that it is comparatively complicated. The process for target product preparation has to be interrupted for a prolonged period and the costs of catalyst preparation are likewise considerable.
What are likewise desired are therefore procedures which are helpful in as far as possible prolonging the lifetime of the fixed catalyst bed in the tube bundle reactor.
As already mentioned, the above is possible to a certain extent in the case of careful operation. Careful operation is understood in the prior art to mean operating the tube bundle reactor, within the context of what is possible, overall, such that, within the individual reaction tubes, as far as possible, a uniform reaction behavior and hence also a very uniform profile of the reaction temperature (of the temperature of the reaction mixture and of the temperature of the fixed catalyst bed) is present along the individual reaction tubes.
EP-A 14 71 046, DE-A 20 2006 014 116 U1 and WO 03/059857 recommend, in this regard, performing the heterogeneously catalyzed partial gas phase oxidation of an organic starting compound in tube bundle reactors whose reaction tubes are of very uniform construction.
According to the teaching of JP-A 2006-142288, the reaction tube inner surface should additionally have a very low surface roughness in order to ensure very uniform charging of the reaction tubes with fixed catalyst bed.
Such a very uniform charging of the reaction tubes with the same fixed catalyst bed is also recommended by the documents U.S. Pat. No. 4,701,101, EP-A 14 66 883, WO 03/057653, US-A 2006/245992, US-A 2002/136678, WO 2005/051532, WO 03/076373 and JP-A 2004/195279.
At the same time, it is quite generally attempted in heterogeneously catalyzed gas phase reactions to minimize the energy demand required for the conveying of the reaction gas. As a measure for achieving this objective, preference is given to using annular shaped catalyst bodies for the configuration of the fixed catalyst bed, since they cause a particularly low pressure drop in the course of passage of the reaction gas through the fixed catalyst bed (cf., for example, WO 2005/03039). A further advantage of annular shaped catalyst bodies normally consists in reduced diffusion pathways and, resulting from this in many cases, in an improved target product yield.
In the simplest case, such an annular shaped catalyst body consists only of catalytically active composition which may, if appropriate, be diluted with inert material (which is, for example, in many cases incorporated for reinforcement reasons) (if appropriate, shaping assistant is also present; for example graphite). Such annular geometric shaped catalyst bodies are typically referred to as annular unsupported catalysts.
However, a disadvantage of annular unsupported catalysts is their generally not fully satisfactory mechanical stability in the course of filling into the reaction tubes. Although this can be improved by an increase in their wall thickness, a disadvantage of relatively large wall thicknesses is that they are accompanied by a lengthening of the diffusion pathway out of the reaction zone, which promotes undesired subsequent reactions and hence reduces the target product selectivity.
A resolution of the contradiction which exists in the case of unsupported catalyst rings between required mechanical stability (increasing wall strength) on the one hand and limiting of the diffusion pathway out of the reaction zone (decreasing wall strength) on the other hand, while maintaining the otherwise particularly advantageous ring geometry, is opened up by annular coated catalysts. These are annular shaped catalyst bodies which consist of an annular (mechanically particularly stable) (catalytically inactive) shaped support body which is generally inert with regard to the gas phase partial oxidation and a catalytically active composition (active composition) applied to its surface.
It can be prepared, for example, by coating the annular shaped support bodies (generally consisting of catalytically inactive (frequently oxidic (e.g. hard-fired)) material; consisting of inert material) with finely divided active composition using a generally liquid binder. Alternatively (or in a mixture with finely divided precursor composition), the shaped support bodies may also be coated with a finely divided precursor composition of the active composition using a generally liquid binder, and the conversion to the active annular shaped catalyst bodies can be effected by subsequent (for example oxidative and/or reductive) thermal treatment (if appropriate in an atmosphere comprising molecular oxygen). The coating can be effected in the simplest manner, for example, by moistening the surface of an inert annular shaped support body (or else simply just "support body") by means of a liquid binder and then adhering finely divided (pulverulent) active composition or finely divided (pulverulent) precursor composition on the moistened surface. Subsequently, normally at least a portion of the liquid binder (generally under the action of heat) is volatilized before the annular coated catalysts are ready to charge a reaction tube (a further thermal treatment can be effected, for example, within the reaction tubes (for example for the purpose of removing residual binder [cf., for example, DE-A 102005010645])). Alternatively, the annular shaped support bodies can also be sprayed with a suspension of finely divided active composition and/or finely divided precursor composition.
Instead of coating the generally inert annular shaped support body with finely divided active composition or with finely divided precursor composition, the annular shaped support body can in many cases also be impregnated with a solution (a molecular and/or colloidal solution) of the catalytically active substance or with a solution of a precursor substance and then the solvent can be volatilized and, if appropriate, a chemical reduction and/or thermal treatment (if appropriate in a molecular oxygen-comprising atmosphere) can follow. The annular shaped catalyst bodies which result in this way are frequently also referred to as supported or impregnated catalysts in the literature. However, they will likewise be encompassed in this document under the generic term "coated catalysts".
Descriptions of processes for preparing annular coated catalysts which are suitable as catalysts for heterogeneously catalyzed partial gas phase oxidations can be found, for example, in the documents DE-A 290 9671, EP-A 714 700, German application 102007017080.9, WO 2004/108267, DE 10 2005 010 645 A1, DE-A 103 13 209, DE-A 103 25 488, DE-A 103 60 058, DE-A 103 51 269, DE-A 103 50 822, WO 2007/009922, DE-A 100 49 873, German application 102007010422.9, DE-A 40 06 935, DE-A 198 23 275, DE-A 198 39 001, DE-A 198 23 262, DE-A 103 44 844, US 2006/0205978 and EP-A 758 562, and the prior art acknowledged in these documents.
An unwanted by-product, which, though, generally cannot be avoided completely, in the preparation of annular coated catalysts is the formation of adhering pairs of annular coated catalysts. These are two coated catalyst rings which adhere firmly to one another. Their formation is attributable ultimately to the fact that the normally liquid binder typically used to apply the active composition coating to the annular support body in the preparation of coated catalysts is capable of bringing about not only the bonding of active composition and shaped support body but, to a limited degree, also the unwanted bonding of two annular coated catalysts. Essentially, the formation of such adhering pairs is restricted to two types: a) fused adhering pairs and b) tandem adhering pairs.
In the fused adhering pairs, two annular coated catalysts (an annular coated catalyst has the geometry E×I×H (external diameter×internal diameter×height)) adhere to one another by their cylindrical shells (outer walls) essentially over the entire height H. They essentially adhere to one another resting alongside one another at the same height (their outer surfaces adhere to one another).
In the tandem adhering pairs, two annular coated catalysts adhere to one another by their annular cross-sectional areas which delimit the particular coated catalyst ring at the top and at the bottom. The upper ring surface of one coated catalyst ring adheres on the lower ring surface of one coated catalyst ring adheres (sticks) on the lower ring surface of the other coated catalyst ring. In this way, what is effectively formed is a coated catalyst super-ring which has the same external diameter E and the same internal diameter I as the two coated catalyst rings which constitute it, but whose height is 2 H.
While the formation of tandem adhering pairs in the preparation of annular coated catalysts is essentially unavoidable, fused adhering pairs form in the preparation of annular coated catalysts essentially (in particular) when H is at least >0.5 E.
Overall, the total amount M of adhering pairs of coated catalyst rings formed in the preparation of one production charge of annular coated catalysts, based on the total weight of the production charge, is ≦5% by weight. Usually, M, on the same basis, is even ≦4, or ≦3, or ≦2, or ≦1% by weight. In the case of careful preparation of annular coated catalysts, M, on the same basis, may even be ≦0.8% by weight, or ≦0.5% by weight, or ≦0.3% by weight, ≦0.2% by weight, or ≦0.1% by weight. In general, M is, however, on the same basis, >0, usually ≧0.005 and frequently even ≧0.01% by weight.
Owing to the aforementioned comparatively low amounts of adhering pairs of coated catalyst rings formed, no increased significance was attributed to their presence in the use of production charges of annular coated catalysts for the configuration of the fixed catalyst bed in the reaction tubes of tube bundle reactors.
However, extremely careful investigations by the applicant with regard to the configuration of fixed catalyst beds in reaction tubes of tube bundle reactors using annular coated catalysts have led to the result that, in the case of an unfavorable position of an adhering pair of coated catalyst rings in the fixed catalyst bed disposed in a reaction tube of a tube bundle reactor, the hotspot temperature in this reaction tube can be increased perceptibly merely by the presence of a single adhering pair of coated catalyst rings in the fixed catalyst bed.
However, an elevated hotspot temperature means accelerated aging of the corresponding fixed catalyst bed charge of a reaction tube. In order to compensate at least temporarily for such an accelerated aging process with regard to the desired space-time yield of target product in a heterogeneously catalyzed partial gas phase oxidation performed in a tube bundle reactor, an accelerated increase of THin of the at least one heat exchange medium is required, which in turn causes an additional acceleration of the aforementioned aging process. The ultimate overall effect which results is a reduced lifetime of the fixed catalyst bed charge of the tube bundle reactor, which is undesired for the reasons already described.
The presence of one (or else more) adhering pair(s) of coated catalyst rings is particularly disadvantageous in the fixed catalyst bed of a thermal tube. The profile of the reaction temperature within the thermal tubes arranged in the tube bundle reactor to be representative of all working tubes forms, as already stated, the basis for the control of the overall operation of a tube bundle reactor (for example the control of the loading of the fixed catalyst bed with reaction gas, the control of the composition of the reaction gas mixture, the setting of the particular THin etc).
In general, the control of the overall operation, for safety reasons, is directed to those thermal tubes whose operating data are the most marginal. When these operating data are representative of the operating data of the corresponding working tubes only to a limited degree owing to the presence of adhering pairs of coated catalyst rings in the fixed catalyst bed of the corresponding thermal tubes, this normally leads to the effect that the overall tube bundle reactor is not operated in its optimal operating state.

Process for introducing a portion withdrawn from at least one production charge of annular coated catalysts K into a reaction tube of a tube bundle reactor


In an early-middle stage of a photosensitive drum life cycle, an image forming apparatus uses only a second semiconductor laser having an oscillation wavelength 660 nm to perform writing of an electrostatic latent image on a photosensitive drum surface. In a middle-late stage of the photosensitive drum life cycle, the image forming apparatus starts using a first semiconductor laser having an oscillation wavelength of 440 nm in addition to the second semiconductor laser to perform writing of an electrostatic latent image on the photosensitive drum surface with a combined exposure spot formed at the same position. An exposure control unit gradually increases an output rate of the first semiconductor laser according to an increase in total output of the first and second semiconductor lasers.

1. Field of the Invention
The present invention relates to an image forming apparatus that can perform multiple-exposure processing for forming an electrostatic latent image on an image carrier surface. More specifically, the present invention relates to an intensity control for exposure spots placed one upon another at the same exposure point.
2. Description of the Related Art
A conventional image forming apparatus can form an electrostatic latent image on a charged image carrier surface by performing scanning exposure using a plurality of laser beams and can develop a toner image with charged toner particles supplied onto the electrostatic latent image formed on the carrier surface. For example, a conventional apparatus can use a plurality of laser beams to form an image at the same position on an image carrier.
As discussed in Japanese Patent Application Laid-Open No. 11-326798, using semiconductor lasers differentiated in the size of optical spot is useful to smoothly reproduce a peripheral region of a latent image and form a combined toner image in a desired manner. As discussed in Japanese Patent Application Laid-Open No. 09-169136, a first beam having a beam diameter of 30 μm and a second beam having a beam diameter of 60 μm can be combined with each other while setting the ratio of 5:3 in the light quantity of light emission.
In general, the distribution of exposure amount at an exposure spot formed on an image carrier surface is a Gaussian distribution having a peak value at the center and peripheral values gradually decreasing as the distance from the center increases. Therefore, the electrostatic latent image of an exposure spot formed when electric charge is discharged with a current value corresponding to the exposure amount has an electric potential distribution (distribution of electrostatic charge amount) having a peak value at the center and peripheral values gradually approaching to a charging potential, which reflects the distribution of exposure amount.
The development of a toner image is dependent on a relationship between the potential distribution of an electrostatic latent image at the exposure spot and a development voltage set for a developing device. The potential distribution of an electrostatic latent image has an effect on the size or the density of a developed toner image (refer to FIGS. 9A and 9B). The size or the density of a toner image, even if the electrostatic latent image is the same, changes if any variation occurs in the development voltage or in the electrostatic charge amount of a developer.
More specifically, the size of a toner image if formed by developing an electrostatic latent image at the exposure spot is variable according to the potential distribution of an electrostatic latent image, the development voltage, or the electrostatic charge amount of a developer. If any change occurs in the size of a toner image resulting from the exposure spot, the line width of the toner image obtainable by scanning the exposure spot changes correspondingly. The density of an image formed by arraying development lines is also changed.
As described below, if the image carrier goes into a late stage of its life cycle, an electrostatic latent image having the same potential distribution cannot be reproduced even if the exposure is performed under the same conditions. The line width and the image density cannot be reproduced correctly for the same toner image.
Furthermore, depending on usage conditions of a developing device (e.g., deterioration in toner particles as a recording material) or if any change occurs in environmental conditions, the line width and the image density cannot be reproduced accurately for the same toner image to be produced from the same electrostatic latent image.
Furthermore, as discussed in Japanese Patent Application Laid-Open No. 2003-323009, the exposure of a pixel can be realized by a plurality of lasers. According to the configuration discussed in Japanese Patent Application Laid-Open No. 2003-323009, in order to accurately combine toner images, toner images formed by respective light beams are equalized. It is also required to equalize a combined toner image formed by placing light beams one upon another with each toner image formed by each light beam. Hence, to maintain the latent image potential at an appropriate level, the output power adjustment for each laser is performed every time the number of sheets reaches a predetermined value.
However, according to the configuration discussed in Japanese Patent Application Laid-Open No. 2003-323009, each laser has the same spot size and, if the laser power is adjusted to attain a target density level when the potential distribution changes due to deterioration, the line width of a latent image (potential distribution) changes correspondingly and the line width of a toner image is also changed. On the contrary, if the laser power is adjusted to maintain the same line width, the target density cannot be maintained.

Image forming apparatus having a exposure control unit capable of changing an exposure ratio between a first exposure ratio and a second exposure ratio different from the first exposure ratio when a first exposure unit or second exposure unit exposes an image carrier on the basis of image data for forming an image with a certain density


A shipping cradle for seedlings and the like is both nestable and stackable. When stacked, a gap is formed between vertically-adjacent cradles to permit insertion and removal of trays of seedlings, and to permit visual inspection of the seedlings. A drainage system includes a series of channels and openings that prevent water from draining onto seedlings positioned in the lower cradles. The cradles are lightweight, and can be shipped in the nested position to substantially reduce shipping costs.

Trays of seedlings and the like have been shipped in steel carts having a plurality of shelves and wheels. However, such carts are quite heavy and expensive, and also take up substantial space. Thus, substantial expense is incurred in returning the empty carts due to the weight of the carts and the space required. Furthermore, such carts are quite expensive, and are often lost or stolen during the shipping process, such that substantial additional expense can be incurred due to the replacement cost. Seedlings or other plants have also been shipped in cardboard boxes and the like. However, such boxes may be prone to damage during shipping due to impacts, or to water damage if the seedlings are watered.

Shipping cradle for trays of seedlings and the like


A trailer electronic braking system includes a braking device capable of generating a braking force on a wheel on the trailer, a brake force into the brake cylinders being controllable by a braking ECU. The braking ECU is connected to a standards compliant communication bus on said trailer and is adapted to receive data inputs from sensors on the trailer. An interface to trailer electronics and a communications interface are also provided. The brake system is further adapted to transmit a trailer identifier such as an SSID, such that the trailer identifier can be paired with a further device, such as a mobile telephone associated with a tractor driver, the further device having previously been provided with the trailer identifier.

The trend in modern distribution systems is towards having large distribution depots located on the outskirts of towns and cities near main trunk roads. These large distribution depots have a number of significant logistical advantages for the operators in terms of stock control and speed and ease of distribution of goods. However, depots have become larger with many having dozens or even hundreds of trailers on site and allocated a job at any one time. In particular for larger companies, it has become difficult to track the trailer use in the depot due to the sheer number of trailers and due to the use of standardized trailers having identical appearance.
Furthermore, trailers for many goods are loaded and then moved from a known loading bay to a parking area to await a tractor or prime mover to take it to its destination. Trailers used in this environment will be assigned a trailer number or identifier. To reduce the risk that a driver takes the wrong trailer, there is usually an independent manual check at the exit gate that the driver has taken the correct trailer.
Patent document WO 2005/115811 discusses an anti-theft system for a trailer comprising an immobiliser which is adapted to communicate with an identified mobile telephone.
This system has given rise to significant logistical efficiencies but is still prone to human error and has a high degree of manual input. This slows down the operation of the trailer depot and results in additional costs for operators due to the inefficient use of resources.

KNORR-BREMSE SYSTEM FUR NUTZFAHRZEUGE GMBH


A thin film transistor array substrate is provided. The substrate includes an insulating substrate, a first signal line formed on the insulating substrate, a first insulating layer formed on the first signal line, a second signal line formed on the first insulating layer while crossing over the first signal line, a thin film transistor connected to the first and the second signal lines, a second insulating layer formed on the thin film transistor, the second insulating layer having dielectric constant about 4.0 or less, and the second insulating layer having a first contact hole exposing a predetermined electrode of the thin film transistor, and a first pixel electrode formed on the second insulating layer while being connected to the predetermined electrode of the thin film transistor through the first contact hole.

(a) Field of the Invention
The present invention relates to a liquid crystal display and, more particularly a thin film transistor array substrate with a low dielectric insulating layer, and a method of fabricating the same.
(b) Description of the Related Art
Generally, a thin film transistor array substrate is used as a circuit substrate for independently driving the respective pixels in a liquid crystal display or an organic electroluminescence display. The thin film transistor array substrate has generally gate lines for carrying scanning signals, data lines for carrying picture signals, thin film transistors connected to the gate and the data lines, pixel electrodes connected to the thin film transistors, a gate insulating layer covering the gate lines, and a passivation layer covering the thin film transistors and the data lines. Each thin film transistor is formed with a gate electrode connected to the gate line, a channel-forming semiconductor layer, a source electrode connected to the data line, a drain electrode, a gate insulating layer, and a passivation layer. The thin film transistor functions as a switching circuit where the picture signal from the data line is transmitted to the pixel electrode in accordance with the scanning signal from the gate line.
Liquid crystal displays are now widely used by consumers and the larger the size and the higher the definition of the display, the more popular. However, signal deformation becomes a problem with the larger size and capacity of the displays due to increased parasitic capacitance. Furthermore, as demand for liquid crystal displays for notebook computers having reduced power consumption and increased demand for liquid crystal display TVs with increased brightness, the opening ratio of the liquid crystal displays need to be increased.
To increase the opening ratio, the pixel electrodes over the data line assembly have to be extended to overlap with the data line assembly. In such case, the parasitic capacitance between the pixel electrodes and the data lines is increased. To avoid increases in parasitic capacitance, there should be sufficient vertical spacing between the pixel electrodes and the data lines. To provide such spacing, a passivation layer is usually formed with an organic insulating film. However, there are problems associated with the formation of the passivation layer using the organic insulating film. First, the material cost is high because there is a large amount of material loss from the spin coating process. Second, the organic insulating film has limited thermostability. Third, the formation of layer using an organic insulating film involves high frequency of occurrence of impure particles. Fourth, the organic insulating film is weaker in adhesive strength with respect to the neighboring layers. Fifth, when pixel electrodes are formed on the passivation layer, there is a high chance of etching error. Accordingly, a need exists for a method and a thin film transistor array substrate having a high opening ratio but without the above problems.

Thin film transistor array substrate using low dielectric insulating layer and method of fabricating the same


Conventional fuel cell systems had the problem of impurity gases flowing back from a buffer tank and a reduction in the voltages of unit cells when the supply pressure of an anode gas is caused to pulsate at startup. An operating method include setting any one of the amplitude and cycle of the pulsation of the supply pressure of the anode gas to a fuel cell stack (FS) in accordance with the permeability of a nitrogen gas from a cathode side to an anode side. The method makes it possible to suppress unnecessary pulsation of the supply pressure of the anode gas at startup, and thus to maintain the concentration of a hydrogen gas in the fuel cell stack (FS) at an optimum level while preventing degradation in the mechanical strength of a membrane electrode structure that constitutes each unit cell (FC) of the fuel cell stack (FS).

A fuel cell system described in, for example, Patent Literature 1 is a conventional fuel cell system of a non anode-gas circulation type. The fuel cell system described in Patent Literature 1 includes a fuel cell stack formed by stacking multiple unit cells, and also includes a hydrogen tank, a supply shut-off valve and a pressure regulation valve as a supply system for an anode gas to the fuel cell stack. Moreover, the fuel cell system includes a storage tank (buffer tank) and an exhaust shut-off valve (purge valve) as an exhaust system for an anode off-gas from the fuel cell stack.
The above fuel cell system sets a first control state where the amount of supply of the anode gas to the fuel cell stack is small and a second control state where the amount of supply is large, and switches the first and second control states back and forth. In other words, the supply pressure of the anode gas is caused to pulsate. Thereby, the fuel cell system reduces the accumulation of impurities in some of the unit cells, and pumps and exhausts the anode off-gas to the storage tank.


Volume dimensioning employs techniques to reduce multipath reflection or return of illumination, and hence distortion. Volume dimensioning for any given target object includes a sequence of one or more illuminations and respective detections of returned illumination. A sequence typically includes illumination with at least one initial spatial illumination pattern and with one or more refined spatial illumination patterns. Refined spatial illumination patterns are generated based on previous illumination in order to reduce distortion. The number of refined spatial illumination patterns in a sequence may be fixed, or may vary based on results of prior illumination(s) in the sequence. Refined spatial illumination patterns may avoid illuminating background areas that contribute to distortion. Sometimes, illumination with the initial spatial illumination pattern may produce sufficiently acceptable results, and refined spatial illumination patterns in the sequence omitted.

Volume dimensioning systems are useful for providing dimensional and/or volumetric information related to three-dimensional objects. The objects may, for example take the form of parcels or packages intended for transit via a carrier (e.g., courier) or other items intended for transit. Dimensional and/or volumetric information is useful for example, in providing users with accurate shipping rates based on the actual size and volume of the object being shipped. Dimensional and/or volumetric information may be used by the carrier in selecting and scheduling appropriately sized vehicles and/or delivery routes. The ready availability of dimensional and/or volumetric information for all objects within a carrier's network assists the carrier in ensuring optimal use of available space in the many different vehicles and containers used in local, interstate, and international shipping.
Such may be of particular significant in today's economy where many businesses rely on "just in time" manufacturing. Typically, every supplier in the supply chain must be able to ship necessary components or resources on demand or with very little lead time. Thus, efficient handling of cargo is required. It does a supplier no good to have the desired goods on hand, if the supplier cannot readily ship the desired goods.
Automating volume dimensioning can speed parcel intake, improve the overall level of billing accuracy, and increase the efficiency of cargo handling. Unfortunately, parcels are not confined to a standard size or shape, and may, in fact, have virtually any size or shape. Additionally, parcels may also have specialized shipping and/or handling instructions (e.g., fragile, this side up) that must be followed during shipping or handling to protect the objects during shipping.
There exists a need for new dimensioning systems that may accurately perform volume dimensioning of objects including parcels and packages as well as other objects.

This patent is subject to a terminal disclaimer.

Volume dimensioning system and method employing time-of-flight camera


A digital submodule is included in a software programmable common receive module for receiving IF signals and producing a serial bit stream. The digital submodule is programmable based on a selected application of a plurality of radio applications and, if present, a selected function of a plurality of functions of the selected radio application. The digital submodule may include an analog to digital converter for converting IF signals received from an analog submodule into digital signals. The digital signals are supplied to a programmable signal processing unit which is configured, according to the selected radio application and, if present, the selected function, to perform control functions, processing and analysis of the digital signals and generate output signals. The output signals are then formatted by a formatting unit producing formatted digital signals. The formatted digital signals are then supplied to a system bus. The programmable signal processing unit may include a digital downconverter for selective use depending on the selected application of radio communication, for generating a base signal. Additionally, a central processing unit is included to perform further signal processing for selected radio application.

1. Field of the Invention
The present invention is directed to a digitally programmable receive module including an analog converter submodule and a digital processing submodule of a receive module in a radio that can be digitally reconfigured to operate over a broad radio band and with different signal formats and, more particularly, to a receive module of a system that provides dynamically programmable and configurable channels using digital channel components to maximize reconfiguration flexibility.
2. Description of the Related Art
Many commercial and military applications require multiple communication, navigation, and identification (CNI) or telemetry radio frequency (RF) functions to be performed at a single location. Table 1 lists examples of Communication, Identification, Navigation and Telemetry Radio functions.
TABLE 1 ______________________________________ CNI and Telemetry Radio Functions ______________________________________ Communication Identification HF Clear Voice/Data ATCRBS/IFF Transpond HF AJ IFF Interrogate HF Link 11 Mode S VHF AM TCAS VHF AM Encrypted VHF FM Navigation VHF Encrypted Omega Nav** SINCGARS Loran-C** VHF ACARS ILS Localizer UHF Clear ILS Glideslope UHF Encrypted ILS Marker Beacon Havequick Versions VHF Omni-Range (VOR) Military UHF SATCOM PLRS/EPLRS Airphone TACAN JTIDS Distance Measuring Equipment (DME) Commercial SATCOM Precision DME RAM Mobile Data GPS Cellular GLONASS Citizens Band Radar Altimeter* PCS Microwave Landing System (MLS)* Commercial TV Automatic Direction Finding (ADF)** Telemetry ACMI ______________________________________ *Indicates that a block converter is used in an antenna interface unit to convert a radio signal to a selected input range. **Indicates that either a block converter in the antenna interface unit o a direct internal connection to the analogto-digital converter is used.
The conventional method for servicing multiple CNI functions is to use independent radio frequency (RF) receive modules, each covering a specific portion of the RF band corresponding to a specific CNI function.
Various applications require greater than 10 different types of CNI radios. At one extreme, communication, navigation and identification (CNI) multi-radio suites are comprised of independent and different type radio channels for each radio functional thread. At the other extreme, integrated programmable radio systems, now in development, cross-couple various elements of multiple channels, which results in a highly complex system of tightly coupled resources.
Both approaches, including hybrids of the two approaches, have advantages as well as major disadvantages. For example, when redundancy is required, the independent channel systems must have separate and different backup radios for all important systems, such as instrument landing systems (ILS), which can be very costly. Further, size and weight of the system precludes implementation of multiple CNI functions in many manpack and vehicular applications. The cross-coupled systems are extremely difficult to maintain because fault isolation is difficult due to the complexity of signal distribution and switching and discourages addition of new or modified functions due to a high cost of system redesign and recertification.
A programmable common digital radio is needed which provides an integrated solution for many different types of multi-function CNI suites provided in a small size, with a light weight at a low cost, without the disadvantages suffered by other architectures as described above.

Common receive module for a programmable digital radio


A water level sensor includes a magnetic tube and a float disposed on a vertical oval rod portion of the magnetic tube. A magnetic switch is contained in the magnetic tube and connected with a power cord. The float has a center hole for the vertical oval bar to extend therein, an inner annular wall extending down to define the center hole with an outer annular wall, and an open lower end closed with a cap. And a magnetic ring is fixed around the center hole on an upper surface of the float. When the float moves down to a preset lower level in water of a tank, the magnetic ring and the magnetic switch produce induction to turn off the power to prevent the tank from burning owing to no water therein.

This invention concerns a water level sensor, particularly keeping a water level at a preset height in a tank for preventing the tank from burning owing to no water therein.
Conventional drink water dispensers are provided with a tank disposed with a water level sensor to prevent the tank from burning. As the tank keeps water therein at a certain temperature or boils it, and if water in the tank becomes too little or is used up, the tank will be burned unless a water level sensor senses the water level and activates to turn off electric power.
A conventional water level sensor shown in FIG. 5 includes a magnetic tube 11, a sleeve 14 and a float 15 combined together. The magnetic tube 11 has straight projections 111 on an outer surface, an annular groove 112 for an elastic ring 113 to fit therein for keeping the sleeve around the magnetic tube 11. A magnetic switch 12 is disposed inside the magnetic tube 11 and connected with a power cord 13.
The sleeve 14 is a hollow tube, having straight grooves 141 in an inner surface, a vertical bar 142 formed to extend up from a center portion having straight projections 143 on an outer surface, an annular groove 144 near an upper end for an elastic ring 145 to fit therein for keeping the float 15 combined with the vertical bar 142.
The float 15 is shaped cylindrical, having a lower end open, an inner annular wall 150 defining a center hole for the vertical bar 142 to extend therein, two straight grooves 151 in the inner surface of the inner annular wall, an annular cavity 152 defined between the inner annular wall 150 and an outer annular wall, several annular engage members 153 on a lower end surface for fitting annular rings 16 therein, and then gaskets 17, 18 fitted around an inner surface and an outer surface and closed with a bent cap 19 on the lower open end of the float 15.
In using, referring to FIG. 6, as the water level sensor 1 is fixed with a side wall of a tank at the magnetic tube 11, and the sleeve 14 is combined with the magnetic tube 11 by means of the straight grooves 141 engaging the straight projections 111, and the elastic ring 113 fitted in the annular groove 112 to position the sleeve 14 in place. Then the vertical bar 142 is inserted in the float 15, letting the straight grooves 151 engaging the straight projections 143. Then the elastic ring 145 is fitted in the annular groove 144 to limit the position of the float 15, which moves up and down according to a water level. When the water level is too high or low, the float 15 moves also to activate the magnetic switch 13 to cut off the power coming from the power cord 13. Thus the tank can be prevented from burning with no water therein.
The conventional water level sensor has too many components and thus its cost is comparatively high. Besides, when the water level falls to a preset certain location, the magnetic ring 16 and the magnetic switch 12 produce induction to activate the power to be cut off. However, the magnetic switch 12 is separated from the magnetic ring 16 by the thickness of the magnetic tube 11 and the inner annular wall 150 so that magnetic force may sometimes not be transmitted well, causing induction impossible to be produced and failing to cut off the power even if the water level should fall down below the preset certain level.


The Hamming distance of an array of storage devices is increased by generating a parity check matrix based on column equations that are formed using an orthogonal parity code and includes a higher-order multiplier that changes each column. The higher order multiplier is selected to generate a finite basic field of a predetermined number of elements. The array has M rows and N columns, such that M is greater than or equal to three and N is greater than or equal to three. Row 1 through row M−2 of the array each have n–p data storage devices and p parity storage devices. Row M−1 of the array has n−(p+1) data storage devices and (p+1) parity storage devices. Lastly, row M of the array has N parity storage devices.

1. Field of the Invention
The present invention relates to storage systems. In particular, the present invention relates to a system and a method that utilizes a modified parity check matrix for increasing the number of storage-unit failures that the array can tolerate without loss of data stored on the array.
2. Description of the Related Art
The increased storage capacity of Hard Disk Drives (HDDs) and HDD-based storage systems are being used for storing large quantities of data, such as reference data and backup data, in a rare write, infrequent read access (near-line storage) configuration. Another exemplary application storing a large amount of data is the Picture Archive and Communication System (PACS) with which about 6600 hospitals in the U.S. yearly generate nearly 1 PB of medical imaging data. Yet another exemplary application storing a large amount of data is an e-mail system, such as Microsoft Hotmail e-mail system, which is purportedly approaching a PB in size. Accordingly, the increased storage capacity places stringent failure tolerance requirements on such HDD-based storage systems.
A known system uses low-cost HDDs that are configured in a RAID 5 blade as the basic building block. Multiple blades are then configured as a further array, such as in a RAID 1 or RAID 5 configuration, for enhancing the failure tolerance. Such an arrangement has the appearance of being a product of two parity codes, yet implementation as a nested array significantly reduces failure tolerance.
For example, FIG. 1 shows an exemplary array 100 of fifteen HDDs configured as three blades. Each blade contains five HDDs in a 4+P RAID 5 configuration. The blades are further configured as a 2+P RAID 5. Accordingly, blade 101 includes HDDs D11, D12, D13, D14 and P15, in which HDDs D11, D12, D13 and D14 store data and HDD P15 stores parity information for blade 101. Blade 102 includes HDDs D21, D22, D23, D24 and P25, in which HDDs D21, D22, D23, D24 store data and HDD P25 stores parity information for blade 102. Blade 103 includes HDDs P31, P32, P33, P34 and P35, in which HDDs P31, P32, P33, and P34 respectively store parity information for columns 111–114 and HDD P35 stores parity information for blade 103 (and for column 115). As indicated in FIGS. 1–5, 6 and 8, the first digit of an HDD designator represents the blade or row number of the HDD and the second digit represents the column number of the HDD.
The general arrangement of FIG. 1 is commonly referred to as a product code because it is the product of two parity codes. The minimum distance of a product code is the product of the individual distances or, in this case, 4. In a product code, many reconstructions must be performed iteratively.
FIG. 2 depicts exemplary array 100 of FIG. 1 having four HDDs failures that are correctable as the product of two parity codes. In FIG. 2, HDDs D11, D12, D22 and D23 have failed, as indicated by an X through each failed HDD. While a nested array configured as a RAID5(RAID5) is also distance 4, in general, such a configuration cannot recover from the particular failure arrangement shown in FIG. 2. In the case of the nested array, Blades 101 and 102 are both unable to correct the two failures with the inner RAID, and the outer RAID cannot recover from two blade failures. In contrast, a product code can recover from the failure arrangement shown in FIG. 2 because the HDDs are not viewed as virtual HDDs. HDD D11 is recovered by the column 111 parity, and HDD D23 is recovered by the column 113 parity. Following these two operations, blades 101 and 102 each have only a single failure, and can be recovered by the respective row parity. While stronger than a nested array, the product code is still only distance 4.
In general, product codes of this type are called products of parity stripes, and are known. There are, however, many failure combinations that product codes cannot correct. For example, FIG. 3 depicts exemplary array 100 of FIG. 1 in which HDDs D12, D13, D22 and D23 have failed, as indicated by an X through the HDD. This particular set of disk failures is not correctable because the product of two parity codes does not provide a linearly independent set of parity equations.
What is needed is a technique for improving the fault tolerance of an array of HDDs beyond to the capability of conventional product code techniques.

Generalized parity stripe data storage array

International Business Machines Corporation


The present invention is a part positioning mechanism configured to insert a protruding portion constituting a part of a second sheet metal part into an opening formed in a first sheet metal part. The first contact portion which contacts the first convex portion of the first sheet metal and the second contact portion which contacts the second convex portion of the first sheet metal are disposed to be shifted in an orthogonal direction which intersects orthogonally with the plate thickness direction and an insertion direction for the protruding portion. The edge of the opening of the first sheet metal part has a first edge which is distant from the protruding portion increases from the first convex portion to the second convex portion, and a second edge which is distant from the protruding portion increases from the second convex portion to the first convex portion.

As in a case of a main body frame of a conventional image forming apparatus such as copiers and laser beam printers, when a frame is constituted by sheet metal parts, the sheet metal parts are normally positioned.
Now an assembly of a main body frame, which is constituted by left and right side plates and sheet metal parts and molded units disposed between the left and right side plates, will be described. In the case of assembling this main body frame, the left and right side plates are temporarily held by an assembling jig at positions outside the assembly position. At this time, sheet metal parts and molded units are temporarily held by the assembling jig between the left and right side plates. Then the left and right side plates are moved inward by a slider mechanism of the assembling jig, so that the sheet metal parts and the molded units are positioned with respect to the left and right side plates and fixed to the left and right side plates by a clamp, and then tightened by screws.
For a positioning structure in such a case, a positioning structure, in which a protruding portion of one sheet metal part is inserted into a hole of the other sheet metal part so as to support the protruding portion at three points inside the hold, is known, as disclosed in the following PTL 1 and PTL 2.

Part positioning mechanism and image forming apparatus