Dainippon Screen Mfg. Co., Ltd.

Takuya Yamaguchi

Osamu Kitagawa

Toshio Kasamatsu

An apparatus records a halftone area and a solid area in a single image with respective, different screen angles. Encoders (13, 14) and a coordinate value generator (16) generate coordinate values (U, V) on an image plane on a recording drum. An address generator (17), a pattern data memory (18) and a comparator (19) generate a first halftone dot signal (S.sub.da) for the halftone area. An address generator (22) and a pattern data memory (23) generate a second halftone dot signal (S.sub.db) for the solid area. A threshold data setter (20) and a comparator (21) generate a detection signal (S.sub.s) which indicates whether or not an image signal (S.sub.i) corresponds to the solid area. One of the first and second halftone dot signals (S.sub.da or S.sub.db) is selected by a selector (24) according to the detection signal (S.sub.s).

Method of and apparatus for recording halftone image

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.

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Kyoto, Japan

Takuya Yamaguchi