Abstract: A print data processing pipeline for use in a color electrophotographic printer optimizes print quality and minimizes memory usage by separately processing lossy and lossless print data. Lossy print data may include print data for images and lossless print data may include print data for text, line art, and graphics. Partitioning print data into lossy and lossless components allows application of the print data compression operations optimized for each type of print data. High compression ratios can be achieved on lossy print data by applying visually lossless compression operations designed for the lossy print data. In addition, high compression ratios can be achieved on the lossless print data by applying lossless compression operations designed for the lossless print data. A merge unit combines the lossy and lossless print data streams after decompression to reconstruct the original image.

Abstract: An apparatus for generating interpolator input data for a color space conversion from a RGB color space to a CMYK color space includes an address generator having eight outputs and a memory having eight inputs each connected to one of the address generator outputs. The inputs to the address generator are the three sets of four higher order bits, RH, GH, and BH, of the twenty four bit RGB color space value and two bits for selecting one of the dimensions in the CMYK space to which the conversion will be directed. From these inputs, the address generator can generate 19,652 addresses for accessing interpolator input data stored in the memory. The address generator simultaneously generates eight addresses for accessing interpolator input data stored in the memory.

Abstract: An apparatus for routing interpolator input data for a color space conversion from a RGB color space to a CMYK color space includes a selective two's complementer coupled to a hardware interpolator. The inputs to the selective two's complementer include three sets of four lower order bits, RL, GL, and BL of a twenty four bit RGB color space value and three least significant bits of three sets of four higher order bits, RH, GH, and BH. The inputs to the hardware interpolator include three outputs from the selective two's complementer and eight inputs for receiving interpolator input data from eight memory banks. The interpolation process can be regarded as determining a location within a cube of a cubic lattice formed from vertices represented by the interpolator input data values.

Abstract: A hardware implementation of a method of decompressing delta row compressed data to uncompressed data having line buffer memory 70 with incrementally advanceable current address 72. Offset counter 78 is used to determine the number of repeating bytes of data stored in line buffer memory 70 for a first row are to be reused in a second row, and replacement counter 76 is used to store the number of sequential replacement data bytes. A RAM controller state machine 84 reads data bytes from line buffer memory 70 to a laser printer engine, and after reading, checks through decompression state machine 82 to determine if a replacement data byte is called for at the current address in the next row of data, writing it in if called for, otherwise, merely incrementally advancing to the next current address in the line buffer memory.

Abstract: A laser printer includes a Resolution Enhancement driver for causing modulation of image edge pixels. The printer comprises a laser for discharging an electrophotographic surface in accordance with an applied modulation signal. A control processor applies modulation signals to the laser in accordance with received commands. A format controller determines if an image pixel resides at an edge of an image feature and, if so, selects a pixel modification to enhance a representation of the feature edge. The format controller, in conformance with the selected pixel modification, generates an encoded command to the control processor that enables the generation of an appropriate laser modulation signal.

Abstract: A fiber-hydratable cement composition comprising a uniform dispersion of from 0.0001 to 10 volume percent interground fiber in hydratable cement powder is prepared by introducing fiber precursors and cement clinker to a grinding mill and grinding the mixture until the clinker has been reduced to a fine powder. The fiber can be steel, alkaline resistant glass, ceramic, carbon or organic polymer, and preferably are steel, polyolefin or mixtures thereof.

Abstract: A multi-color, electrostatic, laser printing system employs a method for enhancing color representations at boundaries of pixels with different colors. The system employs a charged electrostatic surface that is selectively discharged by application of a modulated laser beam. The system performs the steps of: identifying a pixel of a first color that bounds a pixel of a second color, the first color being a secondary color; decreasing applied laser power to the electrostatic surface at the secondary color pixel site in the process of applying underprint and overprint toners to produce the secondary color; and inhibiting the decrease of applied laser power when applying the overprint toner if the second color pixel is a primary color that is the same as the color of the overprint toner of the secondary color pixel. A similar inhibition action occurs when an isolated primary color pixel or a thin pixel line is found so as to assure proper development.

Abstract: A concrete permeability testing core comprises a cylinder of polymeric foam enclosed within an elastomeric envelope under tension. When placed in a cylindrical concrete mold in an axially concentric orientation, it can be used to form a concrete test specimen with a cylindrical cavity. After the concrete is cured and the outer concrete mold is removed, the polymer foam can be collapsed by contacting it with solvent for the foam. The elastomeric envelope, being under tension, contracts to a smaller size, permitting easy removal from the concrete and leaving a nascent cavity surface.