Hewlett-packard Company

Anthony D Parkhurst

Alpha N Doan

Padmanabhan Ramchandran

Thomas J Halpenny

In one embodiment of the invention, the conventional three-step ROP process for filling in arbitrary shapes with a pattern is modified to require less computation and memory. In a preferred embodiment, a printer driver routine installed in the host computer converts the conventional ROP instructions into a modified set of instructions which are then transmitted and processed by the printer. A masking buffer in the printer supports the process. The improved method only requires the fill pattern to be transmitted once to the printer instead of twice, resulting in memory savings of up to 50% and speeding up the print time significantly. In contrast to the three-step ROP process, the first step (ROP 90) of XORing the fill pattern with the destination area is deleted. The arbitrary shapes for being filled are transmitted to the printer, and these shapes are stored in a temporary masking buffer. The fill pattern is then transmitted to the printer and ANDed with the mask so that only the fill pattern coinciding with the area of the mask is forwarded for printing.

Arbitrary masking technique for filling in shapes for display

Quality of printed images as produced by an ink-jet printer (10) is improved by staggering applications of ink dots (30) to pixel locations (36) such that overlapping ink dots are printed on successive passes of a printhead (16) and such that swaths (38) are partially printed on overlapping passes of the printhead. Quality of multi-colored or multi-shaded images is further improved by grouping pixels (36) into super pixels (42), and applying various combinations of colored ink dots to the various pixels within each super pixel in a staggered sequence.

Interlace printing process

A plotter continuously performs a dynamic sort on incoming vectors to be plotted and stores the sorted vectors by color in bins within a memory. At the same time that the sort is being performed, the plotter selects the bin containing the most vectors and plots all of the vectors from that bin before selecting another bin.

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Oceanside, CA, United States of America

Anthony D Parkhurst