Abstract: A multifunction image-transfer system with printing, scanning, digital copying, and facsimile capabilities detects skew as sheet media is fed. A skew processor digitally skews image data as a function of sheet-feed skew detected by skew detectors. In the context of a scanning operation, an image-bearing document is fed to a scanner device, which generates a digital raster image. A buffer stores portions of the digital image as it is transferred. The image data in the buffer is digital skew-compensated before it is transferred to a host computer. In the context of a printing operation, raster print data is stored in the memory buffer and then skew compensated before the image is printed to the print media. The digital skew compensation allows mechanical tolerances in such systems to be relaxed and system lifetimes to be lengthened since “true” images can result despite moderate media skew.

Abstract: A system and method for minimizing distortion in printed images due to toner explosion receives the incoming image bit stream and monitors the stream for horizontal lines and edges that would be particularly susceptible to toner explosion distortion. When such features are determined, the bit stream is modified to print an outlined area with a fill pattern therein. This decreases the amount of toner used to print the horizontal line or edge. As less toner is required, toner piles transferred to the paper are shorter and, therefore, tend to generate less distortion when toner explosions occur.

Abstract: An image forming device having a fast draft mode accomplished by speeding up the media through the image forming device but not changing the image data rate. The image data is scaled to compensate for the increased media speed. The image data may also undergo enhancement processes to increase the quality of the printed image.

Abstract: An improved system and method for data compression/decompression are disclosed. A data compression system may comprise an input memory, a plurality of data compressors, and a controller. In preferred embodiments, the controller selectively forwards data compressed with the most efficient data compressor over sub-portions of a data stream. A data decompression system may be implemented with an input memory, a data compression method identifier, and a plurality of data decompressors. In preferred embodiments, the data compression method identifier selectively applies an appropriate data decompressor over sub-portions of a compressed data stream. A method for compressing data can be summarized by the following steps: receiving a data stream; applying a plurality of data compression algorithms to the data stream; determining which of the plurality of data compression algorithms was most effective; buffering the compressed data; and generating a record indicative of which the applied data compression algorithms.

Abstract: An improved system and method for data compression/decompression are disclosed. A data compression system may comprise an input memory, a plurality of data compressors, and a controller. In preferred embodiments, the controller selectively forwards data compressed with the most efficient data compressor over sub-portions of a data stream. A data decompression system may be implemented with an input memory, a data compression method identifier, and a plurality of data decompressors. In preferred embodiments, the data compression method identifier selectively applies an appropriate data decompressor over sub-portions of a compressed data stream. A method for compressing data can be summarized by the following steps: receiving a data stream; applying a plurality of data compression algorithms to the data stream; determining which of the plurality of data compression algorithms was most effective; buffering the compressed data; and generating a record indicative of which the applied data compression algorithms.

Abstract: An image forming device having a fast draft mode accomplished by speeding up the media through the image forming device but not changing the image data rate. The image data is scaled to compensate for the increased media speed. The image data may also undergo enhancement processes to increase the quality of the printed image.

Abstract: Color optical image scanners, optical scanners, and methods of scanning color images are described. In one embodiment, variations in a velocity profile of a moving object to be scanned are compensated for by selecting for illumination during greater velocity regions, colors having lesser degrees of sensitivity to a human eye. In another embodiment, manipulation of color planes of a scanned object takes place to provide improved images with reduced color artifacts.

Abstract: A method of sending a facsimile of a document includes diffusing a grayscale image to produce a binary, black-and-white image having on/off image values corresponding to a first spatial resolution. When communicating with a remote facsimile device that supports a lower resolution, the black-and-white image is converted to a lower resolution. To perform this conversion, a scaled value for each image value of the lower-resolution image is calculated by interpolating between neighboring dots of the original black-and-white image. The resulting scaled values are then error diffused to create a black-and-white image.