Canon Kabushiki Kaisha

Eri Goto

Hiromitsu Yamaguchi

Tsuyoshi Shibata

Takashi Ochiai

Satoshi Wada

Yoshitomo Marumoto

Yasunori Fujimoto

Makoto Akahira

Ryoki Jahana

In a multipass printing system, a quality image is printed even when the number of passes is reduced to increase a printing speed. For this purpose, in a multipass printing system which repetitively alternates a printing scan, which causes the print head to eject ink from the nozzles as it moves in the main scan direction, and a feeding operation, which feeds a print medium in a sub scan direction, the feed distance of the print medium is set according to a density of an image being printed on the print medium.

Ink jet printing apparatus and ink jet printing method

A printing apparatus divides printing elements of a printhead into blocks, time-divisionally drives the printing elements, and prints a halftone image on a printing medium in accordance with a result obtained by performing digital-halftoning for input multi-valued image data in each matrix of a predetermined size. The apparatus includes a scanner for reciprocally scanning the printhead, a conveyor for conveying the printing medium in a direction different from a scanning direction of the printhead, and a controller for printing a halftone image in each matrix. An arrayed direction of the printing elements is the convey direction of the conveyor. The controller sets a size of the block to be equal to or an integral multiple of a size of the matrix in the convey direction. The digital-halftoning increases the number of dots from a center of the matrix as a density expressed by the multi-valued image data increases.

Printing apparatus and printing method

A spliced ink-jet head including head chips, each of which is capable of discharging inks of two or more colors, and which are spliced in a staggered manner which restrains the occurrence of splice streaks, white streaks caused by deflection at ends or uneven colors attributable to different landing orders of ink droplets in spliced portions of different colors when one-pass recording is carried out. The head chips is arranged such that, in a relationship between two adjoining head chips, at least one discharge port of one head chip and one discharge port of the other head chip for the same color tone ink in end portions overlap on a line in a recording material feeding direction, while discharge ports for different color tone inks do not overlap.

Ink-jet head and ink-jet recording apparatus using the head

An inkjet printing apparatus which performs time-divisional driving poses the following problem for at least some gray levels when halftoning control by the unit matrix is performed. More specifically, the shape of a dot cluster in each unit matrix periodically changes due to the mismatch between the unit matrix size and the unit section size of time-divisional driving. For this reason, periodical density unevenness is generated and appears as degradation of the image quality. In order to prevent degradation of the image quality, according to this invention, image data is shifted in accordance with the unit section of time-divisional driving, or the discharge timing of ink from a printhead is shifted.

In an inkjet printing apparatus which generates satellites droplets, problems in an image attributable to the satellites are mitigated as far as possible. For this purpose, each parameter is adjusted to satisfy a relationship such that the distance between positions of placement of a main droplet and a satellite substantially agrees with an integral multiple of the width of an index pattern. As a result, a satellite is likely to be placed in a position overlapping a dot formed by a main droplet printed in the same area of a pixel located in the vicinity of the satellite, which prevents satellites from placement blank positions where no dot should be printed. Thus, the influence of satellites is mitigated, and problems in an image attributable to satellite are reduced.

Growing community of inventors

Yokohama, Japan

Eri Goto