| 摘要 |
PURPOSE:To obtain an easy-to-see copy image which has an invariably small blank by providing a copy magnification setting means which compares a detected image data area with the size of copy paper and sets copy magnification automatically. CONSTITUTION:A microprocessor 55 receives respective sensor outputs, the output of a reflection density detector 35, and respective timing signals at respective input port and outputs respective control signals from resepctive output ports to set copy density and copy magnification. The reflection density of each picture element in the image area is detected by the photodetecting element group 71 of the reflection density detector 35 and the image area is obtained from the borner between sets of picture elements with a high and a low reflection factor. This image area is compared with the copy paper size obtained with cassette size input keys 571-573; when copy paper of the same size is found, a copy of same size is taken and when not, the microprocessor 55 makes a proper selection of reduction or enlargement to take a copy with specific magnification. In this case, an input voltage corresponding to the maximum and minimum values of reflection factors in the set of picture elements with the low reflection factor is appllied to an irradiation lamp to determine the potential of a drum 1, thereby obtaning a copy image with density determined by development characteristics. |
