Abstract: Compensation is performed for nonuniformity in a printer. The printer has a photoreceptor and a print head with a plurality of different light sources, each light source capable of producing a plurality of different levels of light. A plurality of stored gain control signals for each light source are related to the light output of that light source. Print job data includes screened pixel levels and a halftone screen specification. The stored gain control signals are adjusted based on the halftone screen specification. The screened pixel levels are modified using the adjusted gain control signals to provide engine pixel levels. Those levels are provided to corresponding light sources to expose the photoreceptor in respective pixel areas with light corresponding to the compensated pixel levels.

Abstract: A method for forming a tactile printed image on a receiver medium using an electrographic printer, comprising forming a sequence of toner particle images on one or more primary imaging members, the sequence of toner particle images including a plurality of annular shapes having associated inner and outer sizes. The inner and outer sizes of the annular shapes varying in a monotonic sequence, such that when the sequence of toner particle images are transferred in register onto the receiver medium the annular shapes are substantially concentric and overlapping, thereby forming a tactile image feature having a hollow core; which is then fixed to permanently attach the transferred toner particle images to the receiver medium.

Abstract: An electrographic printing system for forming a tactile printed image on a receiver medium, comprising an image processing path, one or more printing modules and a fixing subsystem. The image processing path provides a sequence of image patterns including a plurality of annular shapes having associated inner and outer sizes, the inner and outer sizes of the annular shapes varying in a monotonic sequence. The printing modules are controlled to form a sequence of toner particle images corresponding to the sequence of image patterns, and to sequentially transfer the sequence of toner particle images in register onto the receiver medium such that the annular shapes in the toner particle images overlap to form a tactile image feature having a hollow core. The fixing subsystem is used to permanently attach the transferred toner particle images to the receiver medium.

Abstract: Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using respective period sensors. The printed test image is measured along a selected measurement direction and a reproduction error signal representing deviation from aim density is determined. For each period sensor, the autocorrelation of the reproduction error signal for the corresponding period is determined. If the determined autocorrelation exceeds a selected threshold, the reproduction error signal is decomposed at the corresponding period to extract the variation from the measured component. The remaining error signal is separated by frequency terms. The variations from the data at measured periods and the remaining error signal are used to produce a correction signal.

Abstract: A method for forming a tactile printed image on a receiver medium using an electrographic printer, comprising forming a sequence of toner particle images on one or more primary imaging members, the sequence of toner particle images including a plurality of annular shapes having associated inner and outer sizes. The inner and outer sizes of the annular shapes varying in a monotonic sequence, such that when the sequence of toner particle images are transferred in register onto the receiver medium the annular shapes are substantially concentric and overlapping, thereby forming a tactile image feature having a hollow core; which is then fixed to permanently attach the transferred toner particle images to the receiver medium.

Abstract: An electrographic printing system for forming a tactile printed image on a receiver medium, comprising an image processing path, one or more printing modules and a fixing subsystem. The image processing path provides a sequence of image patterns including a plurality of annular shapes having associated inner and outer sizes, the inner and outer sizes of the annular shapes varying in a monotonic sequence. The printing modules are controlled to form a sequence of toner particle images corresponding to the sequence of image patterns, and to sequentially transfer the sequence of toner particle images in register onto the receiver medium such that the annular shapes in the toner particle images overlap to form a tactile image feature having a hollow core. The fixing subsystem is used to permanently attach the transferred toner particle images to the receiver medium.

Abstract: Apparatus for depositing a texture on a receiver includes a data source that provides multilevel input tint data values. A lossy compressor produces compressed multilevel tint data values from the multilevel input tint data values. A decompressor produces multilevel decompressed tint data values from the compressed multilevel tint data values. A texture memory receives those values from the decompressor and provides corresponding multilevel texture pixel data values. A print engine deposits at each of a plurality of pixel sites on the receiver an amount of texture-forming material corresponding to the respective multilevel texture pixel data value. A loader loads into the texture memory a texture set including multilevel texture pixel data values for each of a plurality of textures, and each texture in the texture set corresponds to a respective selected range of multilevel decompressed tint data value.

Abstract: By using a high or low viscosity transparent toner, with respect to the other color toners, and different amounts of transparent toner lay-down, the gloss of an image printed by an electrophotographic device may be adjusted. By also applying the transparent toner as a negative mask, the differential gloss of the image may be reduced while still adjusting the gloss of certain portions of the image. Further, because different gloss levels may appear different at different viewing angles, transparent toner may be laid down to encode a transparent image within the image being printed. Such a transparent image may be useful as, for example, an authentication means for a document. Additionally, by varying the gloss levels on particular aspects of a printed image, multiple images of different gloss levels, which are prominent at different viewing angles can be made, thereby, a three-dimensional image effect can be achieved on the printed page.

Abstract: One or more printers or printing systems are connected to a scanning device. Each printer includes one or more color modules that are used during a printing operation. A printer prints a target for each color module or color channel. The printed targets are then scanned by the scanning device. The printed targets may be rotated to any angle and then scanned by the scanning device. The scanned raster data is processed by a controller to detect non-uniformities in at least one density image and to generate one or more correction profiles for the printer. When an image is to be printed, one or more controllers receive the image data and use the one or more correction profiles to correct or compensate for the non-uniformities during the exposure process.

Abstract: Screened hardcopy reproduction apparatus for applying toner to a receiver using a print engine that may not apply toner uniformly, so the toner applied to the receiver has a non-uniformity. A controller receives an input pixel level and a corresponding input pixel location; a tone-reproduction unit calculates an output pixel level from the input pixel level and a corresponding output pixel location from the input pixel location; a compensator calculates a compensated pixel level from the output pixel level and the output pixel location; and a screening unit calculates a screened pixel level and a screened pixel location from the compensated pixel level, the output pixel location, and a selected screening pattern. The print engine applies an amount of the toner corresponding to the screened pixel level and the non-uniformity to the receiver at a toner location corresponding to the screened pixel location to compensate for the non-uniformity.

Abstract: Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using respective period sensors. The printed test image is measured along a selected measurement direction and a reproduction error signal representing deviation from aim density is determined. For each period sensor, the autocorrelation of the reproduction error signal for the corresponding period is determined. If the determined autocorrelation exceeds a selected threshold, the reproduction error signal is decomposed at the corresponding period to extract the variation from the measured component. The remaining error signal is separated by frequency terms. The variations from the data at measured periods and the remaining error signal are used to produce a correction signal.

Abstract: Toner is applied to a receiver having an area to be folded and a separate area not to be folded. Non-fold and fold-area screening patterns are selected. The non-fold screening pattern has a toner coverage greater than 50% and the fold-area screening pattern has a toner coverage less than 50%. Image data to be applied to the receiver in the area to be folded and the area not to be folded are received. The image data in the area not to be folded are processed using the non-fold screening pattern and the image data in the area to be folded are processed using the fold-area screening pattern to provide screened data. Toner corresponding to the screened data is applied to the receiver. The applied toner is fused to the receiver, so that the area to be folded includes fused toner.

Abstract: A method of printing a job having a type using an electrophotographic (EP) printer includes receiving the job and its type. A processor is used to automatically select a first or a second job mode based on the job type; the first job mode indicates aggressive gray component replacement (aGCR) is used but not clear toner, and the second job mode indicates clear toner is used but not aGCR. The data of the job are processed using the processor according to the selected job mode to provide six separations corresponding to respective colorants. Toner corresponding to the six separations is then applied to the receiver using at least one EP printing module in the EP printer to produce a print image of the job.

Abstract: Electrographic printing wherein raised information, with a distinct tactile feel, can be printed by electrographic techniques. Such electrographic printing comprises the steps of forming a desired print image, electrographically, on a receiver member utilizing standard size marking particles; and in an area of the formed print image, where desired tactile feel, raised information is to be formed, selectively forming such tactile feel, raised information utilizing marking particles of a substantially larger size than the standard size marking particles of the desired print image.

Abstract: Apparatus for depositing a texture on a receiver includes a data source adapted to receive a job specification and provide corresponding texture identification data values. A texture memory receives the texture identification data values from the data source and provides corresponding multilevel texture pixel data values. A loader loads into the texture memory a texture set including multilevel texture pixel data values for each of a plurality of textures, each texture in the texture set corresponding to one or more of the texture identification data values. A print engine deposits at each of a plurality of pixel sites on the receiver an amount of texture-forming material corresponding to the respective multilevel texture pixel data value.

Abstract: Apparatus for depositing a texture on a receiver includes a data source that provides multilevel input tint data values based on a job specification. A lossy compressor produces compressed multilevel tint data values from the multilevel input tint data values. A decompressor produces multilevel decompressed tint data values from the compressed multilevel tint data values. A texture memory receives those values from the decompressor and provides corresponding multilevel texture pixel data values. A print engine deposits at each of a plurality of pixel sites on the receiver an amount of texture-forming material corresponding to the respective multilevel texture pixel data value. A loader loads into the texture memory a texture set including multilevel texture pixel data values for each of a plurality of textures, and each texture in the texture set corresponds to a respective selected range of multilevel decompressed tint data value.

Abstract: Apparatus for depositing a texture on a receiver includes a data source that provides multilevel input tint data values. A lossy compressor produces compressed multilevel tint data values from the multilevel input tint data values. A decompressor produces multilevel decompressed tint data values from the compressed multilevel tint data values. A texture memory receives those values from the decompressor and provides corresponding multilevel texture pixel data values. A print engine deposits at each of a plurality of pixel sites on the receiver an amount of texture-forming material corresponding to the respective multilevel texture pixel data value. A loader loads into the texture memory a texture set including multilevel texture pixel data values for each of a plurality of textures, and each texture in the texture set corresponds to a respective selected range of multilevel decompressed tint data value.

Abstract: Compensation is performed for nonuniformity in a printer. The printer has a photoreceptor and a print head with a plurality of different light sources, each light source capable of producing a plurality of different levels of light. A plurality of stored gain control signals for each light source are related to the light output of that light source. Print job data includes screened pixel levels and a halftone screen specification. The stored gain control signals are adjusted based on the halftone screen specification. The screened pixel levels are modified using the adjusted gain control signals to provide engine pixel levels. Those levels are provided to corresponding light sources to expose the photoreceptor in respective pixel areas with light corresponding to the compensated pixel levels.

Abstract: A method of printing a job having a type using an electrophotographic (EP) printer includes receiving the job and its type. A processor is used to automatically select a first or a second job mode based on the job type; the first job mode indicates aggressive gray component replacement (aGCR) is used but not clear toner, and the second job mode indicates clear toner is used but not aGCR. The data of the job are processed using the processor according to the selected job mode to provide six separations corresponding to respective colorants. Toner corresponding to the six separations is then applied to the receiver using at least one EP printing module in the EP printer to produce a print image of the job.

Abstract: Methods of improving image quality by reducing grain and texture in a printed image are provided. According to one embodiment, a method of reducing grain and texture in an image includes the steps of providing a light color toner and a dark color toner, providing an aperiodic micrononuniformity map, using the aperiodic micrononuniformity map to determine an acceptable domain that includes a plurality of combinations of the light color toner and the dark color toner, and forming an image by selecting one combination of the light color toner and the dark color toner from the plurality of combinations of the light color toner and the dark color toner.