Abstract: One or more reactive color inks are printed under and over black text and graphics areas. That is to say, one or more reactive color inks are first printed in a selected area in which black text and/or graphics are to be printed, then the black text and/or graphics are printed, and finally one or more reactive color inks are then printed over the black text and/or graphics. The use of under- and over-printing of black text and/or graphics by reactive color inks improves several important characteristics of inkjet printing. Specifically, the following improvements are obtained: dry-time, finger smudge, media independence/print quality, waterfastness, strikethrough, less noticeable missing/misdirected nozzles, and no dedicated pens are required. Alternatively, either underprinting alone or overprinting alone may be used.

Abstract: A black printhead is installed in a scanning carriage with at least one primary color printhead on both sides of the black printhead. To reduce the drying time of a printed black ink pattern and to achieve other benefits, a first one of the primary color inks underprints the black ink in a first scan direction, and a second one of the primary color inks underprints the black ink in an opposite second scan direction. To minimize hue shifts due to the different underprinted colors, the black ink is overprinted, during the same scan that printed the underprinted ink and black ink, by a color ink that is different from the underprinted ink, so that the resulting black image printed in both scan directions will contain the same three color components. In one embodiment, the order of print cartridges in the scanning carriage, as viewed from the front of the printer, is cyan, black, magenta, and yellow. Other orders may also be used, and additional colors may be used.

Abstract: A media handling system having an endless belt which carries a media sheet through a print zone achieves improved media advance accuracy by including closed loop feedback control. The position of either a drive shaft which rotates the endless belt or the endless belt itself is monitored to provide feedback to a drive motor. The drive motor is linked to the drive shaft through a gear train. The endless belt is rotated by the drive shaft, either directly, or through rollers mounted to the drive shaft.

Abstract: Accurate advance of a media sheet is achieved by carrying the media sheet on a belt loop support. An upstream pinch roller holds the media sheet to the belt upstream of the print zone. A downstream pinch roller holds the media sheet to the belt downstream of the print zone. A guide shim extends along the media path from a position upstream of the upstream pinch roller, passed the upstream pinch roller under a printhead adjacent to the print zone. The location of a lead edge of the guide shim relative to the print zone determines the minimum bottom margin for the inkjet printing device. The guide shim presses the media sheet to the belt support and keeps the media sheet flat under the inkjet printhead as the printhead moves over the media sheet.