PURPOSE: To reproduce a block copy original including at least a halftone dot picture more than 100 lines per inch accurately by exposing a lithographic plate from the back of the light-transmissible block copy original having the halftone dot picture through a lens.
CONSTITUTION: A lighting light source (halogen lamp) is arranged on the back of an original setting board of an exclusive automatic plate making machine (reflecting mirror system) of a printing board independently of an already set-up light source (front side) for reflecting exposure. The reflected original and the transmitted original are exposed by the reflecting exposure light source and the transmitting exposure light source respectively so that 50% area of the halftone dot can be reproduced in plate making processing. In said method, the block copy original including the halftone dot picture 100 lines or more per inch can be accurately reproduced.
YAMAMOTO KIYOUNOSUKE
NISHINOIRI HIROSHI
| JPS5768832A | 1982-04-27 | |||
| JPS5241004A | 1977-03-30 | |||
| JPS51100808A | 1976-09-06 |