Hewlett-Packard Company

Hewlett-Packard Development Company, L.p.

Michael S Gray

Matthew Grant Lopez

Jason R Arbeiter

D Bradley Short

David Bradley Short

Mark A Overton

Mathew G Lopez

A method of an embodiment of the invention is disclosed that determines calibration factors for a fluid-ejection mechanism that is capable of ejecting differently colored fluids onto media. The energy used to eject fluid for each of at least one of the fluid colors is adjusted based on the calibration factors, so that fluid drop ejections of the fluid colors yield fluid drop masses having a consistent ratio.

Adjustment of fluid-ejection energy to yield fluid drop masses having consistent ratio

A swath printing system and under/overprinting method compensate for the effects of defective printing elements by adjusting the under/overprinting map used during printing regions of a uniform color, typically black, to minimize the adverse impact on print quality of unprinted 'white space' caused by the defective printing elements. A printing element quality detector determines which printing elements are functional and which are defective. Based on this information, a print controller then selects or constructs an under/overprinting map having under/overprinting pixel positions chosen to reduce these adverse effects on print quality caused by the defective printing elements, thus maintaining high image quality for the printed output.

Variable density under/overprinting maps for improving print quality

A device for calibrating a scanner, including a transparent plate installable in the scanner, for supporting a document containing indicia to be transferred, and an elongated calibration label fixed to the plate adjacent to, and parallel, with an edge thereof. The label includes an opaque white substrate having a bottom surface which includes a first zone containing white calibration ink and a second zone containing black calibration ink. The white ink contains machine readable information comprising data for controlling skew, magnification, and document reference while the black ink contains data for controlling black calibration. The top surface of the calibration label includes reference indicia for aiding a user in operating the scanner. The first and second zones are surrounded by an adhesive zone for adhering the label to the plate and for isolating the zones from environmental contaminants. A method is provided for fixing the label to a scanner plate for installation in a scanner bezel.

Image transfer device calibration label and method of making and using same

A method for improving the quality of printing processes involving black pixel depletion by printing composite ink in pixel spaces where a black pixel depletion process leaves unfilled pixel spaces. Black pixel depletion data are employed (for example, a depletion mask is inverted) to generate a composite printing mask which designates pixel spaces which are candidates for being filled in with a composite ink. In a preferred embodiment, edge pixels of black fill areas are excluded from the candidate pixels. In a preferred embodiment, the white pixel spaces are filled in by printing a plurality of different colored inks (e.g., cyan/magenta/yellow or cyan/magenta) within these unfilled pixel spaces. In a preferred embodiment, the composite printing mask additionally serves as an under/overprinting (UOP) map.

Method for improving the quality of printing processes involving black pixel depletion

A swath printing system and pixel depletion methods compensate for the effects of defective printing elements by adjusting the pixel depletion mask used during printing to minimize the amount and location of extraneous unprinted spaces caused by the defective printing elements. A printing element quality detector determines which printing elements are functional and which are defective. Based on this information, an image processor then selects or constructs a depletion mask having depleted pixel positions chosen to reduce the adverse effects on print quality caused by the defective printing elements, thus maintaining high image quality for the printed output. Pixel depletion is preferably performed at the image pixel level, but can alternatively be performed at the color plane pixel level.

Adaptive depletion masks for improving print quality

A document scanner carriage drive belt tensioner includes a pivotally mounted base with integrally formed retainers on the base and scanner housing for holding the base in one of three positions comprising a tensioner spring removal position, a carriage belt installation position and an operative or carriage belt tensioning position, all without the necessity of disconnection of any tensioner fasteners. The tensioner is therefore easily operable by an unskilled user to replace the tensioner spring or scanner carriage drive belt when necessary.

Scanner belt tensioning system

A document scanner having a scanner carriage with an integrally formed light monitor window and tab provides a positive, reliable feedback path for adjusting digital image gain controls to provide a uniform digital image during and after an initial lamp warm up period of time.

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Encinitas, CA, United States of America

Michael S Gray