Color image forming device and method

Facsimile and static presentation processing – Static presentation processing – Attribute control

Reexamination Certificate

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Details

C358S003200, C358S003260, C358S533000, C358S536000

Reexamination Certificate

active

06972871

ABSTRACT:
A color image forming device and method prevent occurrence of pile height moires specific to electrophotographic images in low-frequency areas and conventional moires in a digital screen set of four colors. In the color image forming device, by at least one of a halftone generating part and scanning signal forming unit in an image processing unit, differences among screen angles of three dot patterns corresponding to cyan, magenta and black toner images are in the range about 25 to 40 degrees, preferably 30 degrees; the screen angle of a first dot pattern corresponding to a yellow toner image is made equal to that of a second dot pattern corresponding to the toner image of one of cyan, magenta and black; and the screen of the first dot pattern is brought about 150 to 210 degrees, preferably about 180 degrees out of phase with the screen of the second dot pattern.

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patent: 5291296 (1994-03-01), Hains
patent: 6641241 (2003-11-01), Inoue
patent: JP A 6-133156 (1994-05-01), None
patent: JP A 7-92659 (1995-04-01), None
patent: JP A 11-252388 (1999-09-01), None
patent: JP A 2000-85187 (2000-03-01), None
“Halftone-Angle Combinations for nColor Separations” by Mark Coudray, Screen Printing Journal vol. 3 No.11, Oct. 2003, p. 38-42.
Ide et al., “Pixel Reproduction on Various Screens”, Japan Hardcopy 199, pp.303-306.w/abstract.
Kawamura et al., Halftone Reproduction on Digital Color Printer Based on Electrophotography III—-I H Method and Expansion to the Case with Screen Angles.—-, ELECTROPHOTOGRAPHY, The Society Journal, vol. 25, no.1, 1986, pp.31-41. w/abstract.
Kaji, “Electronic Halftoning in prepress”, Japan Print Institute Journal, no.28, vol.1, pp.10-21. w/abstract.
Fuji Xerox Technical Report, no. 11, 1996, pp.26-33. w/abstract.

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