Facsimile and static presentation processing – Facsimile – Recording apparatus
Patent
1994-01-27
1995-03-28
Reinhart, Mark J.
Facsimile and static presentation processing
Facsimile
Recording apparatus
358523, H04N 121
Patent
active
054022452
ABSTRACT:
A system selectively enables a printer to deposit on a sheet C, M, Y and K color dots at each of the plurality of pixel locations to produce a color image. The system comprises a memory for storing C, M, Y and K color values for each pixel in the color image and a processor for controlling selective deposition of the C, M, Y and K colors. The processor determines a gray value for each pixel location from values stored in the C, M, and Y color planes. The processor subtracts the determined gray value from the C, M, and Y values which correspond to the pixel location and then determines a relationship of the gray value to a non-linear function and in dependence upon the relationship alters the C, M and Y pixel values accordingly. The processor either (1) adds the gray value back to the C, M, and Y values for the pixel location, or (2) adds a first portion of the gray value to the C, M, and Y values for the pixel location and a second portion of the gray value to the K value for the pixel location; or (3) adds all of the gray value to a K value for the pixel location. As a result, the C, M, Y and K values are altered in accordance with the determined gray value. The altered color values are then prioritized and the processor determines which colors should be printed at each pixel location and diffuses color error values to neighboring pixel locations after such determination. The prioritization procedure enables print priority to be given to either the brightest color dot or to the color dot that is most visible to the human eye.
REFERENCES:
patent: 4680645 (1987-07-01), Dispoto et al.
patent: 4743959 (1988-05-01), Frederiksen
patent: 4866514 (1989-09-01), Yeomans
"HP DeskWriter C Printer Driver Development", W. Allen, et al., Hewlett-Packard Journal, Aug. 1992, pp. 93-102.
"Ink and Print Cartridge Development for the HP DeskJet 500C/DeskWriter C Printer Family", C. Maze et al., Hewlett-Packard Jour., Aug. 1992, pp. 69-76.
"Low-Cost Plain-Paper Color Inkjet Printing", D. Kearl et al., Hewlett-Packard Journal, Aug. 1992, pp. 64-68.
Dispoto Gary J.
Fitzhugh Andrew E.
McGuire Michael D.
Motta Ricardo J.
Hewlett--Packard Company
Reinhart Mark J.
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