Abstract: Image rotation systems and methods optimally rotate high addressability binary images by transforming the high addressability image to a quasi-grayscale image having normal addressability. A degree of low-pass filtering may be used in conjunction with resampling the image in the process of generating the normal addressability image for rotation. The quasi-grayscale image is then rotated. The rotated quasi-grayscale image is then converted back to a high addressability binary image using a high addressability halftoning process. The systems and methods provide a process wherein high addressability binary images are rotated without introducing gray-level contours or pattern artifacts such as moiré. Further, the apparatus and method provide compact rotation of high addressability images. The density and edge integrity of the processed image are maintained without introducing false contours.

Abstract: Image rotation systems and methods optimally rotate high addressability binary images in a compact manner. High addressability bit pixels are clustered to form multi-bit pixels. The multi-bit pixel image is rotated +/−90°. A pixel mapping method is employed that realigns high addressability pixels within each target group of pixels in a manner that maintains edge integrity, maintains density, and does not introduce additional false contours. Information regarding neighboring pixel values is used to determine edge information about a given high addressability target pixel group. The edge information includes an edge slope and edge location of the high addressability target pixel group. Based on the rotation angle and the edge information of the pixel group, the target high addressability pixel group is mapped to a preferred pattern. After mapping to a preferred pattern, the high addressability pixel group is rotated.

Abstract: Arrays of light emitting diodes, and LED printbars and electrophotographic marking machines that use arrays of light emitting diode, that have active area geometries that produce compact irradiance profiles. Compact irradiance profiles are achieved by placing the diode electrodes along the outer periphery of the light emitting active areas. When used with gradient index lenses, such light emitting diodes produce light spots having more compact irradiance profiles. When such light emitting diodes and gradient index lenses are incorporated into LED printbars, and when those printbars are used in expose stations of electrophotographic marking machines, improved composite images can result.

Abstract: A light emitting diode structure is thermally stabilized by passing current through heater elements along the sides of the light emitting diode. A heater element is adjacent to and corresponding to each light emitting diode. The heater elements may be a resistive region or a p-n junction. The heater elements may be adjacent along one side of the light emitting diodes or on alternating sides of the individual light emitting diodes. The heater elements may be a single heater strip adjacent and along the length of the array of the light emitting diodes.

Abstract: A method and apparatus are shown for improving bit-image quality in video display terminals and xerographic processors. In one embodiment, each scan line of a source image is ANDed with the scan line above to remove half-bits and thin halftones. In other embodiments, entire blocks of data are processed by bit-block transfer operations, such as ANDing a copy of the source image with a copy of itself shifted by one bit. Also, a source image can be compared to a shifted copy of itself to locate diagonal lines in order to place gray pixels bordering these lines.