Abstract: The present disclosure relates to a method, system and apparatus for calibrating an image forming device using a toner patch sensor which emits and detects light in at a given wavelength. A plurality of toner patches may be deposited onto a control surface, wherein the toner patches include a first toner patch including a first toner, a second toner patch including the first toner deposited over a second toner, and a third toner patch including the second toner. Signals indicative of the reflectivity of the plurality of toner patches and the control surface may be measured by emitting light of a given wavelength in the infrared spectrum and detecting the amount of incident light reflected from said plurality of toner patches and said control surface. The signals indicative of reflectivity may then be used to adjust operating parameters of the image forming device which may then control toner mass density.

Abstract: The present disclosure relates to a method, system and apparatus for calibrating an image forming device using a toner patch sensor which emits and detects light in at a given wavelength. A plurality of toner patches may be deposited onto a control surface, wherein the toner patches include a first toner patch including a first toner, a second toner patch including the first toner deposited over a second toner, and a third toner patch including the second toner. Signals indicative of the reflectivity of the plurality of toner patches and the control surface may be measured by emitting light of a given wavelength in the infrared spectrum and detecting the amount of incident light reflected from said plurality of toner patches and said control surface. The signals indicative of reflectivity may then be used to adjust operating parameters of the image forming device which may then control toner mass density.

Abstract: Methods and systems for estimating single or multi-colored toner coverage on a printed page. One method includes generating color plane bitmaps corresponding to each color in a contone bitmap and calculating pixel coverage values for each of the color plane contone bitmaps. Another method includes receiving image data to be printed, generating color separations for the image data corresponding to available toner colors, printing each color separation on a printed page, scanning each printed page comprising the color separation and calculating toner coverage on each of the scanned printed pages.

Abstract: An electrophotographic device comprises a printhead having at least one laser associated with a corresponding photoconductive surface. Where multiple laser beams are associated with the same photoconductive surface, the laser beams are spaced a predetermined distance from one another in a process direction, which is orthogonal to a scan direction in which the laser beams are swept. The electrophotographic device operates at one of at least two image transfer rates. A controller in the electrophotographic device selectively directs image data to the printhead based, at least in part, upon the selected image transfer rate, the facet resolution, and/or the desired output image resolution. The print speed can thus be adjusted over a relatively wide range.

Abstract: Heat accumulation in a thermal printhead is controlled by printing blocks of data along the print line in two passes when examination of the data shows the potential of excessive heating. The proportion of heat intensive or black parts in each block is determined by data processor 17 by examining the data for a line in memory 19. An accumulation is made assigning blocks having high heat density minus 2, blocks having intermediate heat density minus 1 and blocks having low heat density plus 1. When that figure is at minus two the next block is not printed until a second pass and the accumulation is set to zero. Where the accumulation is minus 1, print power is reduced for the next block, which is printed in the first pass. Excessive heat in the printhead results in machine damage and impaired print quality. A second pass is completely avoided where the data is such that this is unnecessary.

Abstract: Wear on the elements (5) of a printhead (3) is spread by shifting the region of use of the printhead line by line. Font (13) provides information as to whether any character in a line employs the upper three pels or the bottom three pels of a line. For each line which can be printed from different shift positions of the printhead, selection logic controls paper feed (15) to index platen (9) to the least used of a shifted position of printhead. Only those electrodes over the print line in each shifted position are used for printing. This distributes wear without requiring any special ribbon feed. The three pel height is at least as wide as the serifs on most characters, which avoids some electrodes being used for the serifs of given characters in more than one shift position.