Lexmark International, Inc.

Curt Paul Breswick

Bob Thai Pham

Thomas Jon Eade

David Allen Crutchfield

Mohamed Nooman Ahmed

James Ray Bailey

Gretchen Yvonne Gibson

Randall David Mayo

John Philip Bolash

Zachary Nathan Fister

John Booth Bates

Ronald E Garnett

James Alan Ward

David Keith Lane

David Steven Waldrop

Pixel characteristics, such as whether a pixel forms part of the background of an image, are evaluated by computing histograms from pixel color space components, by comparing pixel color space components to threshold values, or by other methods.

Intelligent hardware for detecting color value of an image

A method of transforming a n-bit data packet to a m-bit data packet with a lookup table. The lookup table includes at least one entry data packet and at least one respective delta value associated with each entry data packet. The method includes the acts of receiving an input data packet having n-bits, indexing the lookup table with at least a portion of the input data packet to obtain one of the at least one entry data packet, and decompressing the obtained entry data packet with the at least one respective delta value associated with the obtained entry data packet, thereby resulting in an output data packet having m-bits. The decompressing act includes using a portion of the input data packet to determine the number of delta values called for decompressing the obtained entry data packet. The method can be used in, for example, an image processor.

Method of an image processor for transforming a n-bit data packet to a m-bit data packet using a lookup table

Error diffusion is performed upon input image data. In one aspect, multiple error diffusion processing elements perform error diffusion on a selected pixel in parallel. In another aspect, the error diffusion logic is integrally formed with a fast local memory in the same electronic device, such as an ASIC. The error data produced by the error diffusion logic for a pixel is buffered in the fast local memory until it is to be used by the error diffusion logic on other pixels. In still another aspect, a first-in-first-out (FIFO) buffer regulates or buffers the color image data between the output of a color conversion system, such as a colorant lookup table, and the input an error diffusion processing element. In yet another aspect, the error diffusion logic has tagging logic that produces and stores an indicator, either in the output data stream itself or in a separate area, to indicate whether a raster contains printable data.

Systems and methods for error diffusion

An ink jet printer receives image data defining a pattern of dots in a non-square rectangular grid and prints the pattern of dots on a print medium based on the image data. The pattern of dots consists of at least four interlaced checkerboard arrays of dots printed in four passes of the print head across the print medium, where each one of the four checkerboard arrays is printed during a different one of the four passes. Each of the checkerboard arrays is offset from the other checkerboard arrays by a predetermined spacing in at least one of the first and second directions. The printer prints the second checkerboard array horizontally offset from the first checkerboard array by a distance substantially equivalent to {fraction (5d/4)}, where d is the diameter of the printed dots. The printer prints the third checkerboard array vertically offset from the second checkerboard array by a distance substantially equivalent to {fraction (&minus;d/2)} and horizontally offset by a distance substantially equivalent to {fraction (&minus;3d/4)}. The printer prints the fourth checkerboard array horizontally offset from the third checkerboard array by a distance substantially equivalent to {fraction (&minus;3d/4)}. This dot placement method optimally covers a grid having a resolution of {fraction (4/d)}&times;{fraction (2/d)} dpi with dots having diameters that are much larger than optimal for the resolution of the grid. Thus, the invention avoids excessive dot overlap which could lead to ink saturation of the print medium.

High resolution printing

A system and method for printing an image on a recording medium using vertically aligned printhead having at least one vertical column of nozzles, the image being divided into rows and columns. A raster portion of the image data is selected. The raster data is sectioned into print sections, wherein each print section represents data for one column of nozzles during one scan of the printhead across the print medium. The print sections are grouped into print passes wherein each print pass represents one scan of the printhead across the print medium. Each print pass is rotated and sent to the appropriate channel for printing on the recording medium.

System and method for separating raster data for printing

A print quality enhancement arrangement for a dot matrix printer such as a thermal ink jet printer. The arrangement includes a buffer for receiving 300 dots per inch (dpi) resolution data in the horizontal (print head movement) direction and creates 600 dpi resolution data using image enhancement techniques. The arrangement further includes correction of the higher resolution data to remove pels which are unprintable due to the frequency response of the print elements in the print head. The correction is performed using knowledge of the history of printed pels and the original 300 dpi data. The creation of the higher resolution data and its correction occur 'on-the-fly' as data is being fed to the print head, rather than through the creation of a 300 by 600 dpi bitmap.

Growing community of inventors

Georgetown, KY, United States of America

Curt Paul Breswick