Xerox Corporation

James W Stevens

David Mark Kerxhalli

John Frank Walsh

Thomas M Baretsky

Anne Fitzpatrick

Michael John Martin

Mark A Scheuer

John A Durbin

Jess Robert Gentner

Terri A Clingerman

Rosario A Bracco

Mark Petrush

Carlos O Alva

Wayne A Morganti

Siddharth Rajiv Inamdar

Thomas A Hayes

Rod Stair

Ramakanth Desani

Systems and methods are provided for aligning a video clock with the raster output scanner start-of-scan signal in printing systems. A system and method is proposed to align the pixel clock to an asynchronous reference signal generated in the raster output scanner. The proposed system and method adjusts a phase for a static phase value while performing a dynamic phase shifting for the start-of-scan signal alignment.

Apparatus for alignment of video clock with the ROS start of scan sensor signal in printing systems

A magnification adjustment method for a document processing system having a fixed frequency clock source providing a fixed frequency output signal to a plurality of raster output scanners (ROSs) and a numerically controlled oscillator (NCO)-based adjustable frequency clock source providing an adjustable frequency output signal to the ROSs is disclosed. The method includes: using a controller to determine a frequency setting for a phase increment control input signal to the adjustable frequency clock source; starting the document processing system; using the controller to set a phase accumulator control input to the frequency setting; sending a message to a ROS control module prior to imaging, including the correct clock source to use for the next image, the correct clock source being either the fixed frequency clock source or the adjustable frequency clock source; and applying the correct clock source synchronously to the beginning of an inter image panel zone.

Method and apparatus for process magnification adjustment

Document processing systems and duplex printing methods are presented in which sideto sideprocess magnification errors are compensated for by selective use of two raster output scanner clocks for latent image generation of images destined for first and second sides of a printed substrate, with the second clock speed being increased to compensate for substrate shrinkage due to fusing station heating for two-sided printing.

System and method for printing system process magnification adjustment

A system and method for determining a color separation registration error in a multi-color printing system are provided. The system and method provide for instructing first and second color separations to mark a substrate with first and second fine-periodic-patch images to determine color separation registration error(s). The system and method further provide for determining whether at least an about half-period color separation registration error exists between the first and second color separations.

System and method for determining and correcting color separation registration errors in a multi-color printing system

Reflex writing is a group of algorithms developed to maintain color registration in xerographic systems using multiple imagers, in which sequential color separations are written based on events in the spatial domain. The imaging system includes a raster output scanner imager for the black station and a light emitting diode bar for the color station. A simulated machine clock signal is generated based on a running average of a plurality of actual machine clock periods determined from pulses received from a photoreceptor module drive roll encoder. For each black scanline written the distance the belt travels is tracked using the simulated machine clock signal, and when the black latent image scanline has traveled the known distance between the two imagers, the light emitting diode scanline is written registered with respect to the raster output scanner scanline.

Hybrid imager printer using reflex writing to color register an image

A method for varying a scanline rate of a digital scanner while maintaining a constant integration period. The scanner scans a scanline of an image, integrates an array of photosensors after a first predetermined period of time has elapsed and after a second predetermined period of time has elapsed. One of the predetermined periods is equal to an integration period of the array of photosensors, and the other period is equal to a difference between a time needed to process a scanline of image data and the integration period of the array of photosensors. The scanner produces a scanline of valid image data and a scanline of image data corresponding to the first scanned scanline. The scanner then scans the next scanline of the image. By having a variable dummy or garbage integration period in conjunction with the analog image unit's constant rated integration period to form the scanline period, a scanner can utilize a variable scanline period while maintaining a constant integration period and a synchronous scanning operation so as to capitalize on the increase efficiency of new photosensors and faster microprocessors and other processing circuitry.

Device and method for maintaining image scanner data output rate without

An image input terminal synchronously transfers image data to an image processing system when the effective image data generation rate of the image input terminal exceeds the throughput rate of the image processing system. The image input terminal scans the document at a constant rate, but the constant rate is slower than the normal scan rate for the image input terminal, thereby effectively scanning the document at a higher resolution. To realize an effective image data generation rate equal to the throughput rate, the image input terminal periodically discards D scanlines or skips N-D scanlines of valid image data to give the image processing system ample time to complete the processing of valid image data. The image input terminal, to facilitate a synchronous transfer of image data, will skip D scanlines of valid image data out of N scanlines of valid image data.

Device and method for controlling the scan speed of an image input

An image input terminal synchronously transfers image data to a host terminal when the internal data transfer rate of the image input terminal exceeds the data transfer rate of the host terminal. The image input terminal scans the document at a constant rate, but the constant rate is slower than the normal scan rate for the image input terminal, thereby effectively scanning the document at a higher resolution. To realize an apparent internal data transfer rate equal to the data transfer rate of the host terminal, the image input terminal periodically discards or skips scanlines of valid image data to give the host terminal ample time to complete the transfer of valid image data. The image input terminal, to facilitate a synchronous transfer of image data, will skip N-1 scanlines of valid image data out of N scanlines of valid image data such that N is determined by the data transfer rate of the host terminal.

Method and system for transferring image data between two devices having

A halftone conversion system for converting digital pixels to binary pixels in which individual matrices in a memory having progressively changing x, y matrices of binary pixels are addressed by an address composed of a block of x pixels including the pixel being processed, a block of y lines including the line containing the pixel being processed, and the digital value of the pixel being processed, the pixel located at the x, y coordinates of the addressed matrix providing the binary pixel output.

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Rochester, NY, United States of America

James W Stevens