| 摘要 |
PROBLEM TO BE SOLVED: To provide an image density control method for an electrophotographic copying device capable of preventing the low density part or the blank part of an original picture from being fogged on a copy image and stably obtaining high image quality for a long time in the copy image of the original picture of every kind, that is, both in a character mode and a photographic mode. SOLUTION: As for this copying device; plural reference density marks 1 are put on an original platen glass 2, and the developed image density of plural marks 1 on a photoreceptor 5 is measured by an image density detection sensor 11 and compared and judged by a CPU circuit 12 so as to set optimum grid voltage, exposure and developing bias to perform image forming processing. The optimum image desired by a user is obtained by controlling two or more pairs of target image density by a pair of image density detection sensors 11 and a pair of reference density marks 1. |
