Copying device

Abstract

Abstract PURPOSE:To adjust development density to a proper value automatically by providing a selecting circuit which selects and outputs only a signal corresponding to an original image with the lowest density among signals outputted by respective detecting elements at the same time and a control means which controls development density by using the signal that the selecting circuit outputs. CONSTITUTION:When an original 1 is replaced with an original having a gray background part, detecting elements s1-s4 detect it and their outputs e1-e4 decrease in maximum value. The density variation of the background part is detected as a signal voltage e0, which is compared by a comparator 23 in a control circuit with a reference voltage es to increase the quantity of exposure of a light source 3 immediately, thereby performing compensation so that the background part has specific development density. Consequently, even if an original has extremely deviating density variation, the density of its background part is detected securely and the quantity of exposure is adjusted automatically so as to obtain proper background density.

Inventors

• 👤 Shigeyoshi Takenaka
• 👤 竹中　成嘉
• 👤 Hiroyuki Sugimoto
• 👤 裕之 杉本

Bibliographic Details