| 摘要 |
PURPOSE:To prevent unnecessary operation by indicating that picture density is uncontrollable owing to an abnormal reflection factor and stopping printing operation when the picture density is adjusted by detecting reflection factors of the dark and bright parts of a master. CONSTITUTION:The master 110 is held around a drum 109, and charged by an electrostatic charger 107, toner development by a developing device 116, and transfer to paper 101 are carried out repeatedly to obtain electrostatically printed bodies 106. The passing of the blank and white parts provided at the front end part of the master 10 is detected by position sensors 114 and 115 to adjust a charged potential and a development bias on the basis of the detection result of their reflection factors by a density sensor 113. When it is recognized that the picture density is out of control lable range because the reflection factor of the black part or white part is too high or low, an alarm is generated to stop the device, stopping unnecessary operation. |
