Xerox Corporation

Vaughan Louis Dewar

Lesley P Dudek

Michael C Ferringer

Dale R Ims

Peter A Torpey

An ink jet printing system utilizes a heated rotary printing drum for mounting and carrying paper to be printed by one or more thermal ink jet printheads to achieve black or full color printing at high speed. As printing and drying are achieved prior to any transfer of the sheet from the drum, smudging of images is prevented. Such a printing system is capable of producing dried prints that can be immediately stacked and handled without smudging using slow-drying black inks and fast-drying color inks at speeds exceeding 10 pages per minute for color and 20 pages per minute for monochrome black text or images. Hold down of the sheet onto the drum can be achieved using vacuum or electrostatic forces to precisely retain the sheet on the drum until printing and drying are completed. Partial tone printing on multiple passes of the heated drum is provided to eliminate mottle on large solid areas. Heating of the drum can be performed internally or externally.

Heated drum for ink jet printing

A color ink jet printing device capable of substantially reduced intercolor bleeding includes an ink jet printer having at least one printhead and at least three separate ink supplies in communication with the printhead. A first ink supply contains a slow drying black ink. A second ink supply contains a fast drying black ink. A third ink supply contains a fast drying non-black color ink. Prior to printing, black image potions are determined. The black portions are printed using a pixel priming process, a border substitution process or a combination thereof to reduce intercolor bleed. The pixel priming process first prints a quartertone or halftone pattern using fast drying black ink, followed by subsequent whole tone printing superposed on the primed black image area using a slow drying black ink. The border substitution process analyzes a neighboring matrix of pixels surrounding each black pixel, preferably at least a 5.times.5 matrix, to determine if color pixels other than black are present. If so, that black pixel is printed using the fast drying black ink to reduce intercolor bleed. Otherwise, the black pixel is printed using slow drying black ink. This printing may be further improved by checkerboarding the black image portions. This involves printing a partial tone checkerboard pattern in a first pass and printing a complementary checkerboard pattern on a second pass to provide a whole tone of the image portions.

Growing community of inventors

Bartlett, TN, United States of America

Vaughan Louis Dewar