Creating composite page images from compressed data

#This invention relates to a printer. More particularly, the invention relates to a printhead controller for controlling printing of an image by a printhead and to a method of controlling a printhead.

#According to a first aspect of the invention, there is provided a printhead controller for controlling printing of a page by at least one printhead, the printhead controller being connected, in use, via a data communications link to a printer controller for receiving data, in a compressed format, relating to the page to be printed, the data including a page description comprising a bi-level black layer and a contone color layer, the printhead controller including

#a first decoding means for expanding compressed data relating to the bi-level black layer;

#The invention is now described by way of example with reference to the accompanying drawings in which,

#FIG. 1 shows a plan view of a printer, in accordance with the invention;

#FIG. 2 shows a front view of the printer;

#1 S-Print Overview

#The invention will be described with reference to a high-speed duplex network color printer intended for high-volume office use. It features 2000-sheet motorized paper trays, 120 page-per-minute operation, and 1600 dpi photographic-quality output. We refer to the printer as the “S-print” and we shall refer to it as such or as the printer below.

#With 20 times the speed of the best network color laser printers, and 4 times the speed of the best network monochrome laser printers, S-print effectively targets the $40 billion desktop laser printer market. With its high performance and photographic-quality output, it also competes against offset printing for print runs smaller than 5000 copies.