Landa Corporation Ltd.

David Tal

Shahar Klinger

Alon Siman-Tov

Mattetyahu Litvak

Embodiments of the invention relate to techniques whereby sufficient compensation is provided to counteract the deleterious effects of a malfunctioning nozzle (i.e. which might create a white streak within the printed ink image) in a manner that is faithful to/harmonious with the underlying AM or FM screening. In this manner, it is possible to minimize the negative impact a failed or malfunctioning nozzle has upon the printed ink image.

Method and system for compensating for a malfunctioning nozzle

Printing an image, using a printing system having a malfunctioning or inoperative nozzle corresponding to a column of affected positions in a half-toned digital image, includes modifying the half-toned digital image, using a pre-print digital processor of the printing system to compute a modified version of the half-toned digital image, such that droplet sizes are increased only in the two neighboring columns and according to a value of a compensation function, and printing the modified half-toned digital image on the target surface. Values of the threshold-based compensation function are based on a luminance-debt function defined by an iterative row-by-consecutive-row computation procedure, where for each iteration step the luminance-debt function is re-calculated according to data representing the ink values of affected positions and data representing the instant value of the compensation function.

Methods and systems for compensating for a malfunctioning nozzle in a digital printing system

Some embodiments relate to a method of measuring a magnitude of a yaw angle of print head(s) or of a supporting print-bar thereof relative to cross-print direction. In some embodiments, a 1D-representation (1D-rep) of an ink-calibration image is transformed into the frequency domain (e.g. by FFT) characterized by peak profile. The yaw angle magnitude may be computed from relative energies of a primary and secondary peak of the peak profile of the frequency domain.

YAW measurement by spectral analysis

Apparatus and methods for printing multi-level and multi-color digital image are disclosed herein. In some embodiments, first and second level AM half-tone screens are respectively applied to first and second multi-level color-components of the multi-level and multi-color input digital image to respectively generate first and second target binary images. The first and second target binary images are printed respectively using first and second inks (e.g. of different colors) onto a common surface. Specific properties of the AM half-tone screens as well as techniques for producing the AM half-tone screens are disclosed herein. In some embodiments, the techniques overcome objectionable textures derived from rounding errors in divisional of conventional AM supercells.

AM Screening

Some embodiments relate to a digital printing system and method for depositing ink droplets onto a target surface in dependence upon a received electrical printing signal containing data indicating the desired image to be printed while improving the uniformity of intended tone reproduction of the printed image.

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Rehovot, Israel

David Tal