Lexmark International, Inc.

International Business Machines Corporation

Jeffrey A Minnick

Warren J Spina

Brian Wesley Damon

Cuong Manh Hoang

Christopher Mark Songer

Stephen R Troyer

Terry W Ringle

John Francis Gostomski

Bryan Leslie Ethington

To process bit maps for full color and other data-intense bit maps for printing, a data processing routine (FIG. 4) determines if a block at data within a page is not in color or is otherwise in a single value. Such data is stored in DRAM (28) in one bit per pel form. Other blocks are stored with eight bit for each pel. A table is then developed defining the contiguous order in a page (FIG. 6). An ASIC (32) then transfers the pel information in order of printing to a video RAM (40) with the eight bits restored for data stored in one bit per pel form. The data applied to that ASIC is decompressed.

Printer with high bandwidth compression architecture

A clock circuit (12) normally couples clock pulses to a microprocessor (11), which is capable of accessing memory devices (13,14) having different access times. Access of a 'slow' memory device 14 is detected by the clock circuit, and in response thereto, one or more clock pulses are not coupled to the microprocessor. This suspends operation of the microprocessor for a suitable amount of time so that the microprocessor reads valid data from the slow memory device. The number of clock pulses blocked from reaching the microprocessor can be set in a delay circuit (28) in the clock circuit.

Digital processor clock circuit

A printer having a print engine (13) and a bit map memory (12) including a number of page image areas (31) into which information to be printed is rasterized and from which information for the print engine is serialized. A digital processor (11) controlling the print engine is operable to reduce a page image area (31) to a modified page image area (37) based upon the highest and lowest addresses at which information has been written into the page image area. The digital processor (11) is also operable to begin rasterization of a new page image area when a sufficient amount of an existing page image area (41) has been serialized to make available the requisite bit map memory for the new page.

Bit map memory management for a page printer

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Lexington, KY, United States of America

Jeffrey A Minnick