Dainippon Screen Mfg. Co., Ltd.

Seiko Epson Corporation

Dainippon Screen Manufacturing Co., Ltd.

Osamu Kitagawa

Seiji Mochizuki

Takashi Sakamoto

Masahiro Nakamura

Masayuki Murai

Takuya Yamaguchi

A printer has a head where outlets are arranged in a width direction perpendicular to a predetermined scan direction, and a printing paper moves under the head in the scan direction. In a basic dither matrix which is an array where element values are arranged in a column direction corresponding to the scan direction and a row direction corresponding to the width direction and positions in the row direction are associated with the outlets in the head, respectively, the element values are modified on the basis of variation in print densities with respect to the width direction caused by ejection from the outlets. In the printer, printing is performed with the modified dither matrix, it is therefore possible to print an image at high speed and easily, where unevenness caused by variation in ejection amounts of droplets from the outlets or the like is suppressed.

Printer, dither matrix generation method, and recording medium

In a head unit of a printer, a head (A) has outlet rows (and) arranged along a first tilt direction and a gap between outlets in the outlet rows (and) is interpolated with a outlet in the outlet rows (and) by a slight tilt. A head (C) adjacent to the head (A) is tilted in a second tilt direction opposite to the first tilt direction. In the printer, a plurality of dots are formed, being aligned on a piece of printing paper in the first tilt direction by performing an ejection control simultaneously for all outlets in each outlet row of the head (A) and subsequently a plurality of dots are formed, being aligned on the piece of printing paper in the second tilt direction by performing an ejection control simultaneously for all the outlets in each outlet row of the head (C), to make both rows of dots continuous. Through this operation, the printer can easily perform high-resolution printing without such a complicate ejection control as to control ejection of ink for each outlet ().

Printer and head unit fabricating method

Screen patterns for respective color components are represented by arrays of unit regions. The arrays for respective color components have a same array pitch and a same array orientation. Color component images are converted into color component halftone dot images through the screen patterns. When the density of the color component images is in a predetermined range, the color component halftone dot images have a plurality of linear dot elements in each unit region. The plurality of linear dot elements extend in a predetermined direction which is different for each color component.

Method of recording halftone dot image

A printed image (I.sub.t4) is produced with halftone images for respective color printers while so-called rosette moire and a color shift from an original iamge are prevented. Halftone dots (H.sub.m4, H.sub.c4, H.sub.k4) are formed in linear shapes extending in respective prescribed directions, thereby forming parallel lines with respective intervals (d.sub.m4, d.sub.c4, d.sub.k4). These extensional directions and intervals of parallel lines are so established that they effectively prevent the rosette moire and the color shift.

Method of and apparatus for recording halftone images and halftone

An original drum and a recording drum are driven independently by individual synchronous motors. Encoders output respective rotation timing pulses (P.sub.a, P.sub.b) at every rotation of the recording drum and the original drum. If an interval separating the timing pulses (P.sub.a, P.sub.b) becomes smaller than a prescribed value, a scanning line deviation control circuit generates a motor control signal (T.sub.b) which interrupts the delivery of electrical power to the faster moving motor for a limited period such as to restore a correct relationship between the timing pulses.

Method of and apparatus for preventing scanning line deviation in a

A method of recording register marks by a color scanner for the respective color separation pictures, wherein the register marks are produced by positive and negative linear pictures, or alternatively, by positive linear picture having omitted portions, thereby performing the registering work in an exact and efficient manner.

Method of recording register marks

A method of recording register marks by a color scanner for the respective color separation pictures, wherein the register marks are produced by positive and negative linear pictures, or alternatively, by positive linear pictures having omitted portions, thereby performing the registering work in an exact and efficient manner.

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Kyoto, Japan

Osamu Kitagawa