Hewlett-packard Development Company, L.p.

Ramon Borrell

Antoni S Murcia

Ramon Vega

Xavier Girones

Emiliano Bartolome

Ferran Vilanova

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.

Hardcopy apparatus and method

An arbitrary 3D or 2D shape is formed by construction from colorant in a volume&mdash;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&mdash;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&mdash;the array moving at equal but opposite velocity so that the image is stationary. The frame is a passive sump for colorant recovery, or has a pump for returning colorant to the array for reuse&mdash;in which case the array best ejects colorant of plural properties and the device has filters to separate retrieved colorant by those properties. In some forms, colorant is stroboscopically lighted to display apparent motion of an image element. A force field can be used to control, or help control, colorant position after ejection.

Three- and two-dimensional images formed by suspended or transitory colorant in a volume

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&mdash;selected from many such modules&mdash;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. Interactive effects of environmental conditions and module characteristics are preferably also accounted for. If the printing medium in use has a sensitivity to excessive colorant deposition of colorant, at least one environmental condition that affects that sensitivity of the medium to excessive deposition is also automatically sensed, just before printing; and this information is then automatically used to modify printer operation, to limit the amount of colorant deposited. Instructions for automatic operation are placed in a nonvolatile device at the time of manufacture. Sensitivity data are empirically assembled from test patterns and used, preferably in algebraically signed form in regression calculations, to find coefficients for use in polynomials used to calculate the transfer functions.

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Barcelona, Spain

Ramon Borrell