Abstract: In a method of printing with overlapping printhead dies, artifacts in the printed image caused by the printing nozzles in the overlapping region are removed, either by measuring the width of the band produced in the overlapping region and selecting an appropriate depletion or propletion printing mask for subsequent printing operations, or by printing out a test pattern in which areas corresponding to a range of depletion and propletion masks are printed out and the optimal mask is selected for subsequent printing operations. The dies overlap by only a few rows of nozzles. The method may be employed in fixed printhead apparatus (e.g. page wide arrays) or in a scanning printhead apparatus.

Abstract: In a method of printing with overlapping printhead dies, artifacts in the printed image caused by the printing nozzles in the overlapping region are removed, either by measuring the width of the band produced in the overlapping region and selecting an appropriate depletion or propletion printing mask for subsequent printing operations, or by printing out a test pattern in which areas corresponding to a range of depletion and propletion masks are printed out and the optimal mask is selected for subsequent printing operations. The dies overlap by only a few rows of nozzles. The method may be employed in fixed printhead apparatus (e.g. page wide arrays) or in a scanning printhead apparatus.

Abstract: One invention form is a method using all input data for one or preferably plural colorants, one time to control colorant deposition in forming a pixel array on a printing medium, and at least one other time to control deposition of more of the same colorants. At least one “applying” includes choosing data-array pixels to deposit added colorant. The two data-usage times can be associated directly with depositing colorant in respective printer passes; or may be done at (or near) rendition, sending output data to printmasking for pass allocation. Selection preferably includes setting maximum density on the medium—and choosing locations for that density, best by analyzing data to find locally dense areas, e. g. counting neighboring pixels. Selecting also includes defining locations to receive particular density, and creating additional density levels based on densities in the data array.

Abstract: Apparatus defines a dither mask (DM) and printmask (PM) with corresponding dimensions. In one invention form the DM dimension is not an integral factor or multiple of the PM dimension. The two dimensions may be lengths or widths; preferably the apparatus manages both; the corresponding dimensions differ by at least three pixels, and by a multiple of two pixels—more preferably eight or a multiple of eight. Preferably one dimension is an integral multiple of 256 pixels differing by eight pixels from the other. Another invention form has a scanning printhead making multiple passes across a print medium to form swaths of marks, a mechanism to define an offset smaller than at least one of the two dimensions, and a unit to index one mask by that offset between forming of successive swaths. This is valuable if DM and PM are established by preprogrammed circuits (e.g.

Abstract: An arbitrary 3D or 2D shape is formed by construction from colorant in a volume—which may be cylindrical, annular, or of arbitrary cross-section, depending on form of the invention. In some forms, a 2D-extended array of colorant-ejecting nozzles is disposed in a particular linear direction relative to the volume, and a programmed processor controls ejection of colorant from the nozzles to pass through the volume. A 2D colorant-retrieving frame (ideally back-to-back with the array) is disposed in a second linear direction opposite to the one particular direction, from the array, to recover the colorant and thus erase the image—which can then be refreshed, with animation changes if desired, by the writing array. Colorant is moved through the volume by gravity, or by continuous ejection of material from the array and suction at the frame to form a suspending fluid flow—the array moving at equal but opposite velocity so that the image is stationary.

Abstract: At least one environmental condition that affects color of a printed image is automatically sensed, just before printing. That information is then used to modify printer operation, to compensate specifically for effects of the condition on color. This is preferably accomplished using a transfer function calculated just before printing. Also preferably taken into account is a principal color-calibration profile, not prepared just before printing but rather substantially constant. If a replaceable colorant-placing module is in use—selected from many such modules—and the particular module has a characteristic property (such as drop weight or age of an inkjet pen) which affects the color of printed images, then preferably information about that property of the particular module is also automatically used to modify printer operation, to compensate for effects of the distinctive property on color.

Abstract: In the course of the operation of a bi-directionally printing inkjet printer, travel of the printhead in the left-to-right direction results in the ability to apply colored ink droplets onto a pixel location in one sequence. However, when the printhead moves right-to-left, the sequence by which the colors may be applied is reversed. Therefore, hue shift alters the appearance of a pixel depending on the direction of printhead movement at the time of printing. In one implementation, a system and method of color data translation includes a first color mapping look-up table for left-to-right printhead travel and a second color mapping look-up table for right-to-left printhead travel. Accordingly, greater control over print output is obtained. In particular, hue shift between swaths, wherein each swath is associated with printhead travel in a particular direction, are avoided.

Abstract: The method enables swath-type bidirectional printing without hue shift, using plural scanning multiple-inkjet printheads (holding inks of different colors respectively) and printing-medium advance orthogonal to the scan axis. Inking is calculated and implemented for each position in the grid independently. Images appear as a pixel grid of columns and rows both spaced--i.e. in both the scan and media-advance directions--more finely than 300 dpi. In one aspect of the invention, both these resolutions are the same, and equal to the nozzle spacing. At least some of the nozzles are overlapping and respectively aligned along the advance axis, to be capable of printing on adjacent rows during a single pass. In another aspect of the invention, the nozzle arrays only partially overlap, so as to use significantly fewer than the total number of nozzles in each array.