Abstract: A method and apparatus enhance a color or grayscale raster image in a printer by identifying a working pixel in the raster image for anti-aliasing, and then modifying luminance data of the working pixel in a luminance chrominance color space such that an anti-aliasing effect is achieved relative to the raster image. The luminance component of the raster image data is converted to a binary format to identify the working pixel using RET template matching. The luminance data of the working pixel is modified by utilizing luminance data of adjacent pixels to produce a new luminance value which is then assigned to the working pixel. One of the adjacent pixels defines an edge of the object being anti-aliased in the raster image, and the other of the adjacent pixels defines an edge of a region in the raster image that is adjacent the object.

Abstract: A printer performs both the processing and printing tasks efficiently using controller firmware with a single data path (i.e., one ASIC). The printer has a periodic print cycle in which data for one page or plane (if multi-colored) is printed during each cycle. The print cycle is typically longer than the time needed to print one page or plane. Thus, the print cycle can be segmented into a “printing phase” in which the printing mechanism prints data, and a “non-printing” phase in which the printing mechanism does not print data. The controller firmware interleaves printing operations with non-printing operations during the printing and non-printing phases of the print cycle, respectively. During the printing phase, the controller is dedicated to printing a page or plane. During the non-printing phase, the controller is free to perform other tasks, such as compressing raster data for subsequent printing.

Abstract: Fine pulse width modulation (PWM) adjustments in the output of a laser printer are accomplished by receiving values from a bit map and modifying the values in accordance with values in a lookup table (LUT). The lookup table is subdivided into a plurality of blocks, and a selection of the blocks is made in accordance with external values. This allows the output of a pulse width modulation circuit to be adjusted to a precision that is greater than that afforded by the bit size of the values from the bit map. The use of plural blocks in the lookup table permits adjustments in the output of the pulse width modulation circuit in accordance with external factors such as relative humidity, sensitivity of an optical photoreceptor, and developer life.