Abstract: An optical assembly for an LED printhead includes a longitudinally extending linear lens array. A stiffener bar is attached to the lens array along a substantial longitudinal dimension of the lens array. A lens mount base plate supports the stiffener bar and a pin and slot connection is provided for permitting thermally induced dimensional change in two dimensions of the stiffener bar relative to the lens mount base plate.

Abstract: A method and apparatus for reproducing an original image, having a scanner which scans and digitizes the original image into pixels, a controller coupled to the scanner to receive the digitized original image, and which produces a first signal corresponding to a gray level halftoned representation of the digitized original image, and a printer coupled to the controller to receive the first signal and which produces a gray level halftoned reproduction of the original image. The controller groups the pixels into cells that each have a determined cell gray level, and controls the formation of dots within the pixels of an individual cell by the printer such that for each increase in cell gray level, a dot at at least one of the pixels in the cell forms to a larger dot-size. Sequential forming of the dots occurs at the pixels in the cell in a pre-defined order such that each dot is formed to a first dot-size less than a maximum dot-size before beginning the formation of a dot at another pixel within the cell.

Abstract: An LED Printhead having a row of LED's includes a binary architectured driver that drives each LED on for a series of sub-intervals related to a series of binary weighted recording clocking pulses to record a grey level pixel in accordance with an appropriate series of data bits latched in the driver. The series of data bits are formatted for presentation to the driver by a retransmit line buffer which transmits n times the data of one line of grey level pixels represented by n bits each to a process correction look-up table. Another look-up table provides a signal to the process look-up table as to the intensity characteristics of the particular LED which is to print the pixel. The corrected grey level data is then input to a multiplexer which selects one of the n bits for printing in accordance with count signals related to the binary weight of the recording clock pulses.

Abstract: A non-impact printer apparatus is described that includes a recording head having a plurality of recording elements such as LED's for recording on a recording medium. A plurality of driver chips are provided on the head and each includes a plurality of current driving channels for selectively driving a plurality of recording elements in accordance with respective image data signals. The driver chips each further include an extra current driving channel not associated with a recording element for generating a current related to that sent to said recording elements. Monitoring of the current in the extra channel is provided to permit for changes of current to the recording elements and/or corrected image data to provide fine tuned control over uniformity of the recording elements.

Abstract: A toner image that combines pictorial information with text or graphic information is made glossy only in the pictorial portion. A clear gloss enhancing toner is selectively applied to the portion of the image that is pictorial as determined by a suitable manual input or electronic analysis of the image.

Abstract: Method and apparatus for compressing and enhancing gray-level, halftone, image data in copiers and printers. The input data is digitally halftoned to provide input halftone cells containing a plurality of individual pixels. The pixel density distribution is examined to determine the relative position within the cell of the densest pixels. The gray-level density value for the entire cell is also ascertained. The distribution determines the particular threshold matrix which is used to convert the density value of the input cell into pixel density values which form an output halftone cell. The various matrices have distribution patterns which place the lower threshold values at the position in the output cell corresponding to the position of the densest pixels in the input cell. The cell density value and the matrix selection designator are stored in memory at different bit levels.

Abstract: An image processing system renders halftone images with an increased number of gray level steps without increasing the number of sub-elements in the halftone cells.

Abstract: An input scanner and print engine system corrects for color interpretation errors in the input scanner's color filter set and maps the requested input colors to an output color printable by the printer in a uniform color space. A 3.times.3 transform matrix partially corrects for the color interpretation errors of the color filter set as well as maintaining the neutrality in the transformation and a non-linearly loaded lookup table further corrects the color interpretation errors for outlying datapoints in the actual color space. A color gamut compression lookup table is used to perform non-linear compression for each axis of the color space. Inside the output color gamut, a substantially one-to-one correspondence is performed by the compression table but near the outer color gamut boundary, compression is non-linearly performed. In this manner, colors lying outside of the printable output color gamut are compressed to a region within or on the surface color of the printable color gamut.

Abstract: An LED printhead that includes a plurality of LED chip arrays arranged in a row has areas adjacent end LEDs on each array connected by wires to provide a direct thermal shunt to reduce a temperature gradient between these LEDs.

Abstract: A color image is recorded in narrow band segments by rotating an image member having a cylindrical electrostatographic surface, creating an electrostatic latent image segment on a narrow band of the surface of the rotating image member, developing the latent image segment in a first color, repeating these steps on axially abutting portions of the image member surface until all image segments have been developed in the first color, transferring the developed image to a receiver, and repeating the steps for at least one more color. The latent image segment may be developed by applying pigmented toner particles thereto from a development station having a width corresponding approximately to the width of the image segment. The electrostatic latent image segments may be created by a write head having a width corresponding approximately to the width of the image segment; moving the write head between the axially abutting portions of the image member.

Abstract: In a multi-color electrophotographic reproduction apparatus employing a non-impact electro-optic exposure source, good color balance is obtained by changing the exposure intensity of the recording elements for each different color being imaged. A dot printer apparatus produces a series of different color-resolved electrostatic latent images on a recording member. The apparatus includes an array of discrete elements for dot recording on the recording medium. The elements are selectively enabled for predetermined periods of time during a cycle of operation to form a color-resolved electrostatic latent image on the recording member. Each charged latent image is developed with selected toner particles according to its resolved color. A control signal representative at least in part of the resolved color of each latent image is produced, and the control signal determines the intensity of the elements during each cycle of operation according to each resolved color.

Abstract: A binary architectured LED printhead is driven in accordance with a multiple addressable, i.e., multiple sub-lines of recording, scheme to record grey level pixels. Respective sub-lines are recorded using a series of pulses that form a set of binary-weighted exposure strobe durations. Exposure durations for recording successive strobed sub-lines with a particular LED are ordered so that larger duration strobe pulses are followed by shorter duration strobe pulses. A plurality of strobe enable lines are provided to which respective recording elements are connected. A pulse from this set is generated during a sub-line exposure period on each enable line with each enable line having a pulse generated thereon that is of a different duration than that generated on the other enabling lines during the sub-line recording period and wherein during a sub-line exposure period the respective pulses on the enabling lines are substantially nonconcurrent.

Abstract: Apparatus and method for producing selectively edited reproductions of an original documents with high productivity. Selected areas of information on the originals are bounded by a loop of a first or second type of highlighting material to indicate the area for reproduction in one or more treatment modes such as color-accenting. Alphanumeric character codes, written using the highlighting means, designate the treatment(s) to be applied. The two types of highlighting material respectively indicate that the selected area is located within or outside the boundary. By scanning the highlighted originals, the boundaries are distinguished and the character codes are detected. The resulting output signals are processed using boundary detection and character recognition algorithms and the resulting information is stored in a bit map. The information is used to adjust a charged image version of the original on an image-bearing member using an LED or other light source.

Abstract: Apparatus and method for converting digital, gray-level, image input data into binary valued halftone cells and preserving some of the sharpness information of the original data. The data is first converted to input halftone cells in which the pixel density gradient is analyzed to determine the density distribution within the cells. Depending upon the gradient, particular threshold value templates are selected to be used for thresholding the input data. Each template develops the output pixels beginning at different regions of the output halftone cell. The template for each input cell is selected which grows the binary pixels in the same region occupied by the densest pixels in the gray-level input data.

Abstract: Apparatus and method for producing a page output from electronic input data consisting of text and line graphics information and of pictorial information. The text and graphics information is converted to two-bit per pixel data and stored in a page buffer. The pictorial information is originally stored at its originating pixel resolution and at a bit level sufficient to represent the full color content. This pictorial data is expanded to a finer pixel resolution at a four-bit level, per color, at the time data is to be merged with the text and graphics data. The merging is accomplished in a band or line buffer which combines the two-bit and four-bit data. A location table is used to keep track of the bit level transitions and to signal the output device that the data is in a particular format.

Abstract: Apparatus and method for producing a page output from electronic input data consisting of text and line graphics information and of pictorial information. The text and graphics information is converted to two-bit per pixel data and stored in a page buffer. The pictorial information is originally stored at its originating pixel resolution and at a bit level sufficient to represent the full color content. This pictorial data is expanded to a finer pixel resolution at a four-bit level, per color, at the time data is to be merged with the text and graphics data. The merging is accomplished in a band or line buffer which combines the two-bit and four-bit data. A location table is used to keep track of the bit level transitions and to signal the output device that the data is in a particular format.

Abstract: Automatic identification of continuous-tone segments of an original document so that such segments can be screened is accomplished by converting the original image into a series of electrical signals characteristic of the optical density gray level of image pixels, calculating the gray level histogram for pixels within defined regions of the original image, and providing signals related to the position of the continuous-tone segment on the basis of the gray level histograms for each region of the original image.

Abstract: A process is provided for the non-electrostatic transfer of a toned image. Using an intermediate transfer roll from an element to a receiver, a developed toned image on the surface of an element is transferred by pressure and heat to a transfer roll. The heat is sufficient to sinter the toner particles to each other. The roll is then positioned against a receiver and rolled thereover and the toned image is transferred to the receiver. If the combination of heat and pressure is sufficient, the transferred toned image is fused to the receiver during the transfer; if not, then the transferred image can be subsequently fused to the receiver. The process is suited for producing high resolution images from very small particle size toner powder on rough paper.

Abstract: A halftone threshold value supermatrix produces different screen frequencies between density steps, but at the same screen angle so as to provide image processing for rendering halftone images with an increased number of gray level steps without changing the apparent screen angle between density steps. A gray level pixel value is compared to a threshold value to make a print or no print decision. The threshold value may come from a j.times.k threshold value supermatrix divided into four equal submatrices of elements such that there is one more ON element in one of the submatrices than in the other three when there are an odd number of ON elements and there are the same number of ON elements in each of the submatrices when there are an even number of ON elements in the supermatrix.

Abstract: A master sheet for use in reproducing an original image in a xeroprinting system comprises a transparent supporting dielectric layer, a photoconductive layer, a transparent conductive layer between the dielectric and photoconductive layers, and a mask of opaque material deposited upon the exposed face of the dielectric layer in a predetermined pattern according to the original image. Exposure of the photoconductive layer to light directed through the mask causes a latent image to be formed on the master sheet. A xeroprinting drum assembly for use in a xeroprinting system is also provided wherein a rotatable support drum is wrapped with an electroluminescent (EL) sheet and then the master sheet. The drum assembly may be rotated while the EL sheet selectively exposes the photoconductive layer to provide a latent image. Alternatively, a slit light source may be used.