# US 8,570,543 B2 · Device and method for improving xerographic voltage uniformity for an image recording apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,543 B2 - Document ID: US8570543B2 - Status: Granted - Kind: B2 - Application number: 13/028,703 - Filed: 2011-02-16 - Published: 2012-08-16 - Granted: 2013-10-29 - Earliest claimed: 2011-02-16 - Assignees: Xerox Corporation - Applicants: John R. Washington - Inventors: John R. Washington - Web page: https://patentgrep.com/patent/US8570543B2 ## CPC - G03G 15/043: with means for controlling illumination or exposure (G03G15/041 takes precedence) - G06K 15/1247: {using an array of light sources, e.g. a linear array} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract An image recording apparatus including a memory element and a processor for a specially programmed general purpose computer. The memory element stores correction data for a plurality of locations on a photoreceptor for the image recording apparatus. The processor is for: inducing a charge on the photoconductive layer; receiving image data including, for said each location in the plurality of locations, a first or second desired voltage level; calculating, using the correction and image data, respective desired output power levels for a LED printbar for the apparatus, aligned with the plurality of locations, to discharge each location to the one of the first or second desired charge level, the respective desired output power levels selected to compensate for variances of respective induced charge levels at the plurality of locations; and supplying respective power inputs to the plurality of LEDs to generate the respective desired output power levels. ## Claims ### Claim 1 A computer-based method for improving xerographic voltage uniformity in an image recording apparatus, comprising: storing, in a memory element for at least one specially programmed general purpose computer, correction data for a plurality of locations on a photoconductive layer of a photoreceptor for the image recording apparatus; inducing a charge, using a processor for the at least one specially programmed general purpose computer, on the photoconductive layer; receiving, using the processor, image data for producing an image using the apparatus, the image data including, for said each location in the plurality of locations, one of a first or second desired voltage level; calculating, using the processor, the correction data, and the image data, respective desired output power levels for a plurality of light emitting diodes (LEDs) in a printbar for the apparatus, aligned with the plurality of locations, to discharge said each location to the one of the first or second desired charge level, the respective desired output power levels selected to compensate for variances of respective induced charge levels at the plurality of locations; and, supplying, using the processor, respective power inputs to the plurality of LEDs to generate the respective desired output power levels. ### Claim 2 (depends on 1) The computer-based method of claim 1 wherein the correction data includes, for each location in the plurality of locations, a respective variance, with respect to a desired induced charge level for the photoconductive layer, of a respective actual induced charge level. ### Claim 3 (depends on 1) The computer-based method of claim 1 wherein: the first desired charge level is for a print area for the image; and, the second desired charge level is for a blank area for the image. ### Claim 4 (depends on 1) The computer-based method of claim 1 wherein: the plurality of locations on the photoreceptor is across a width, orthogonal to a process direction, of the photosensor; or, the plurality of locations on the photoreceptor is along a length, parallel to a process direction, of the photosensor. ### Claim 5 (depends on 1) The computer-based method of claim 1 wherein a thickness of the photoconductive coating is different at said each location. ### Claim 6 A computer-based method for improving xerographic voltage uniformity in an image recording apparatus, comprising: storing, in a memory element for at least one specially programmed general purpose computer, correction data for a plurality of locations across a width of a photoconductive layer for a photoreceptor for the image recording apparatus, the correction data including respective variances, with respect to a desired induced charge level, of respective actual induced charge levels; applying, using a processor for the at least one specially programmed general purpose computer, voltage to the photoconductive layer such that the respective actual induced charge levels differ from the desired induced charge level according to the respective variances; receiving, using the processor, image data including respective desired charge levels for the plurality of locations, the respective desired charge levels being one of a second or third charge level; storing, in the memory element, respective output power levels for a plurality of light emitting diodes (LEDs) in a printbar for the apparatus, the plurality of LEDs aligned with the plurality of locations; determining, using the processor, the stored respective output power levels, and the correction and image data, that the respective output power levels for the plurality of LEDs are insufficient to discharge the plurality of locations to be within a first range of the second desired charge level or to be within a second range of the third desired charge level; and, modifying, using the processor and the correction and image data, power supplied to the plurality of LEDs such that the respective output power levels of the plurality of LEDs are sufficient to discharge the plurality of locations to be within the first range of the second desired charge level or to be within the second range of the third desired charge level. ### Claim 7 (depends on 6) The computer-based method of claim 6 wherein: the first desired charge level is for a print area for the image; and, the second desired charge level is for a blank area for the image. ### Claim 8 (depends on 6) The computer-based method of claim 6 wherein a thickness of the photoconductive coating is different at each location in the plurality of locations. ### Claim 9 A computer-based method for improving xerographic voltage uniformity using a module installable in and removable from an image recording apparatus, comprising: storing, in a memory element for the module, correction data for a plurality of locations on a photoconductive layer of a photoreceptor included in the module; installing the module in the image recording apparatus; inducing a charge, using a processor for at least one specially programmed general purpose computer, on the photoconductive layer; receiving, using the processor, image data for producing an image using the apparatus, the image data including, for said each location in the plurality of locations, one of a first or second desired voltage level; calculating, using the processor, the correction data, and the image data, respective desired output power levels for a plurality of light emitting diodes (LEDs) in a printbar for the apparatus, aligned with the plurality of locations, to discharge said each location to the one of the first or second desired charge level, the respective desired output power levels selected to compensate for variances of respective induced charge levels at the plurality of locations; and, supplying, using the processor, respective power inputs to the plurality of LEDs to generate the respective desired output power levels. ### Claim 10 (depends on 9) The computer-based method of claim 9 wherein the correction data includes, for each location in the plurality of locations, a respective variance, with respect to a desired induced charge level for the photoconductive layer, of a respective actual induced charge level. ### Claim 11 (depends on 9) The computer-based method of claim 9 wherein: the first desired charge level is for a print area for the image; and, the second desired charge level is for a blank area for the image. ### Claim 12 (depends on 9) The computer-based method of claim 9 wherein: the plurality of locations on the photoreceptor is across a width, orthogonal to a process direction, of the photosensor; or, the plurality of locations on the photoreceptor is along a length, parallel to a process direction, of the photosensor. ### Claim 13 (depends on 9) The computer-based method of claim 9 wherein a thickness of the photoconductive coating is different at said each location. ### Claim 14 An image recording apparatus with improved xerographic voltage uniformity, comprising: a memory element for at least one specially programmed general purpose computer for storing correction data for a plurality of locations on a photoconductive layer of a photoreceptor for the image recording apparatus; and, a processor for the at least one specially programmed general purpose computer for: inducing a charge on the photoconductive layer; receiving image data for producing an image using the apparatus, the image data including, for said each location in the plurality of locations, one of a first or second desired voltage level; calculating, using the correction data and the image data, respective desired output power levels for a plurality of light emitting diodes (LEDs) in a printbar for the apparatus, aligned with the plurality of locations, to discharge said each location to the one of the first or second desired charge level, the respective desired output power levels selected to compensate for variances of respective induced charge levels at the plurality of locations; and, supplying respective power inputs to the plurality of LEDs to generate the respective desired output power levels. ### Claim 15 (depends on 14) The apparatus of claim 14 wherein the correction data includes, for each location in the plurality of locations, a respective variance, with respect to a desired induced charge level for the photoconductive layer, of a respective actual induced charge level. ### Claim 16 (depends on 14) The apparatus of claim 14, wherein: the first desired charge level is for a print area for the image; and, the second desired charge level is for a blank area for the image. ### Claim 17 (depends on 14) The computer-based method of claim 14 wherein: the plurality of locations on the photoreceptor is across a width, orthogonal to a process direction, of the photosensor; or, the plurality of locations on the photoreceptor is along a length, parallel to a process direction, of the photosensor. ### Claim 18 (depends on 14) The computer-based method of claim 14 wherein a thickness of the photoconductive coating is different at said each location. ### Claim 19 An image recording apparatus with improved xerographic voltage uniformity, comprising: a memory element for at least one specially programmed general purpose computer for: storing correction data for a plurality of locations across a width of a photoconductive layer for a photoreceptor for the image recording apparatus, the correction data including respective variances, with respect to a desired induced charge level, of respective actual induced charge levels; and, storing respective output power levels, for a plurality of light emitting diodes (LEDs) in a printbar for the apparatus, the plurality of LEDs aligned with the plurality of locations; and, a processor for the at least one specially programmed computer for: applying voltage to the photoconductive layer such that the respective actual induced charge levels differ from the desired induced charge level according to the respective variances; receiving image data including respective desired charge levels for the plurality of locations, the respective desired charge levels being one of a second or third charge level; determining, using the stored respective output power levels and the correction and image data, that the respective output power levels for the plurality of LEDs are insufficient to discharge the plurality of locations to be within a first range of the second desired charge level or to be within a second range of the third desired charge level; and, modifying, using the correction and image data, power supplied to the plurality of LEDs such that the respective output power levels of the plurality of LEDs are sufficient to discharge the plurality of locations to be within the first range of the second desired charge level or to be within the second range of the third desired charge level. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein: the first desired charge level is for a print area for the image; and, the second desired charge level is for a blank area for the image. ### Claim 21 (depends on 19) The apparatus of claim 19 wherein a thickness of the photoconductive coating is different at each location in the plurality of locations. ### Claim 22 A module for an image recording apparatus, comprising: a photoreceptor with a photoconductive layer; and, a memory element for storing correction data for a plurality of locations on the photoconductive layer of the photoreceptor, wherein: the module is insertable into and removable from the image recording apparatus; and, when the module is installed in the image recording apparatus, a processor for at least one specially programmed general purpose computer is for: inducing a charge on the photoconductive layer; receiving image data for producing an image using the apparatus, the image data including, for said each location in the plurality of locations, one of a first or second desired voltage level; calculating, using the correction data and the image data, respective desired output power levels for a plurality of light emitting diodes (LEDs) in a printbar for the apparatus, aligned with the plurality of locations, to discharge said each location to the one of the first or second desired charge level, the respective desired output power levels selected to compensate for variances of respective induced charge levels at the plurality of locations; and, supplying respective power inputs to the plurality of LEDs to generate the respective desired output power levels. ### Claim 23 (depends on 22) The apparatus of claim 22 wherein the correction data includes, for each location in the plurality of locations, a respective variance, with respect to a desired induced charge level for the photoconductive layer, of a respective actual induced charge level. ### Claim 24 (depends on 22) The apparatus of claim 22, wherein: the first desired charge level is for a print area for the image; and, the second desired charge level is for a blank area for the image. ### Claim 25 (depends on 22) The computer-based method of claim 22 wherein: the plurality of locations on the photoreceptor is across a width, orthogonal to a process direction, of the photosensor; or, the plurality of locations on the photoreceptor is along a length, parallel to a process direction, of the photosensor. ### Claim 26 (depends on 22) The computer-based method of claim 22 wherein a thickness of the photoconductive coating is different at said each location.