Abstract: A printer processor prints out two sheets of test prints by printing a test pattern on two recording sheets of different lengths. The test pattern consists of eight straight-linear lines that are parallel to a main scan direction or a sub scan direction of an exposure section. Dimensions of designated portions of the test pattern are measured on each of the test prints, to detect skew characteristics of the recording sheets, deviations of print starting positions in the main and sub scan directions and fluctuations in transport speed of the recording sheets. Based on the detected values, a skew correcting section, the exposure section and a conveyer device for the recording sheets are controlled to correct skew of the recording sheets, the print starting positions in the main and sub scan directions and the transport speed.

Abstract: The method and system for printer color calibration use a combination of a full-width array (FWA) or similar page-scanning mechanism in conjunction with a spectrophotometer color measurement system in the output path of a color printer for measuring colors with or without requiring any manual operations or operator involvement. The automatic color balance control system produces spatial tonal reproduction values for the primary colors by printing patches, measuring colors using the sensor combination and automatically readjusting the spatial tone reproduction curves until a satisfactory level of printed color accuracy and uniformity are obtained.

Abstract: A method and system for rotation-dependent halftone rendering. An image input is received from a scanning system or other source, the received image being either a contone image or an error-diffused mage. If a following right-angle image rotation is to be performed, the image is clustered by a clustering method which yields reduced file sizes with respect to the rotated orientation of the image. If no following right-angle image rotation will be performed, the binary image is clustered by an alternate clustering method which yields reduced file sizes with respect to the non-rotated image. The selective clustering includes dividing the image into a tessellation of cells and then concatenating like bits in each cell in a preferred direction for the rotated or non-rotated image. The clustered image is then rotated if necessary, and compressed.