Abstract: In a printer, a controller keeps track of the imager's operation. The original image is transferred into a continuous tone image by using a tone reproduction curve. That signal is encoded into gray pixel data by a halftoner. The pixel data contains the pixel location and the desired darkness of gray, i.e., amount of toner deposited. An imager uses the pixel data to generate the final halftoned image in a printer. A controller generates a feedback signal based on the printer's operation and the quality of the final halftoned image. The imager uses the feedback signal to modify the encoded gray pixel data in order to adjust the final halftoned image. The original coding of the image into gray pixel data is generic and does not depend on the characteristics of the printer being used. This invention reduces the computation of gray pixel data and allows the imager to be separate from the apparatus generating the gray pixel data.

Abstract: A gray pixel encoding scheme is used in combination with a halftoner and an imager to produce halftoned images. A halftoner and an imager can be totally separate because the gray pixel encoding allows the imager to decode them at any time. The encoded gray pixels require less bandwidth than explicit gray pixels and can be decoded by the imager in an optimal fashion for the characteristics of the specific printer being used. An imager produces a small partial pixel within a spot boundary. The subpixel produced is called a gray pixel. The gray pixel is allowed to grow from a zero width to a full spot width and is allowed to start anywhere within the spot. The pixel codes describe the starting positions of the gray pixels, the locations of the gray pixels within the spot, and the gray pixel width required. The imager uses the encoded gray pixel from the halftoner to produce a final halftoned image.

Abstract: A technique to identify colorimetric properties of toner contained within a cartridge in a reproduction machine by embedding in a PROM within the cartridge specific coordinates of a color coordinate system and entering the color coordinate information into the data base of the machine to accurately map color data from one color domain such as a full color domain to another color domain such as a highlight color domain.

Abstract: A document background control system having a sensor in the optical path of a reproduction machine to sense the background of a document in the copy mode during the scanning of the document to adjust the illumination of the document and also includes a control to adjust the charging potential on the photoconductor in response to document background that is non-white.

Abstract: An improved single component magnetic toner composition with a resistivity of from about 10.sup.13 to about 10.sup.16 ohm/cm, at 1,000 volts, and comprised of:(a) first resin particles of a styrene methacrylate copolymer grafted with or containing a low molecular weight wax composition;(b) second resin particles of a styrene, acrylate, acrylonitrile terpolymer;(c) a major amount of magnetite particles; and(d) islands or patches of carbon black particles in an amount of from about 0.1 percent to about 1 percent by weight, contained on the surface of the resin particles.