Dainippon Screen Mfg. Co., Ltd.

Masayuki Sasahara

Hiroshi Shibazaki

Hideaki Kitamura

Katsuya Yamaguchi

Yoshio Sugimoto

Each image area in a total image is assigned with a screen angle mode Ms indicating whether screen angles of magenta and cyan separations are to be adjusted or not. Screen angle data representing screen angles of magenta and cyan are produced according to the screen angle modes Ms. A dot signal for recording a halftone image of each of the magenta and the cyan separations is generated by comparing screen pattern data of a certain screen angle specified by the screen angle data with image data for each color separation. Accordingly, the present invention effectively prevents a moire in any image area included in a printing image.

Method and apparatus for generating halftone images with adjusted screen

An original image which is painted with at least first and second colors is subjected to a coloring process wherein a pixel block of M.times.N pixels in an original image is replaced by a representative pixel to generate a low density image. Then a subject image area is specified in the low density image, and the subject image area is painted with a desired color. The low density image is then magnified to form a high density image, and the high density image and the original image are compared with each other whereby another image is composed from the two images. Black image areas in the composed image area are finally changed to white. In the composed image, the desired color is allocated to pixels which have the desired color in the high density image and which are black in the original image while 'white' is allocated to the other pixels. Pin holes, which are not specified as subject image areas, are not filed with the desired color, and are eliminated simultaneously when the subject image area is filled with the desired color.

Coloring of designated image area and pinhole elimination by image

An original mounting sheet attached to a scanner drum for positioning originals for reading a plurality of originals in an image reproducing apparatus such as a color scanner comprises a first reference line along a subscanning direction of a scanner, two second reference lines along the main scanning direction and a third reference line intersecting the first reference line for specifying at least two intersecting sides of the original. The original is positioned on the original mounting sheet with at least one intersecting corner specified.

Layout position designating sheet and method of mounting original using

An original image is represented in a run-length format. Run-length of each image region is compared with a predetermined reference value, and if the former is smaller than the latter, the run-length (l) is divided into two values (l.sub.1, l.sub.2). The two values are added to the run-length of image regions adjacent thereto, respectively. As a result, a linework (R1) included in the original image is erased without leaving a blank on the erased area.

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Kyoto, Japan

Masayuki Sasahara