Dainippon Screen Mfg. Co., Ltd.

Shinji Shiraishi

Yutaka Tamura

In order to prevent a line break phenomenon in reproduction of an image of an original in halftone dots, RGB signals of an original (2) are contour-enhanced by a USM circuit (10), and inputted in a halftone dot signal producing circuit (30) and an edge signal producing circuit (40). The halftone dot signal producing circuit (30) converts image signals (Y-IMA to Bk-IMA) to halftone dot signals (DOT1 to DOT10) at the timing of a clock signal (CL1), to output the halftone dot signals (DOT1 to DOT10) to a synthesizing circuit (11) in response to a first output start signal (ENST). However, an output start time is delayed from the time of receiving the signal (ENST) by a time required for the halftone dot processing. On the other hand, an edge signal producing circuit (40) produces a contour signal (BE, WE) from the image signals at the timing of a clock signal (CL2) having a higher frequency than the clock signal (CL1), and outputs the same in response to a second output start signal (ENSTD) which is delayed by the aforementioned time from the signal (ENST). The synthesizing circuit (11) synthesizes the halftone dot signals (DOT1 to DOT10) with the contour signal (BE, WE), thereby producing exposure signals (EX1 to EX10).

Growing community of inventors

Kyoto, Japan

Shinji Shiraishi