| 摘要 |
PURPOSE:To select a copy density accurately with one operation when the copy density is set manually, by providing an indicator where the copy density adjusted automatically in accordance with the density of an original to be copied is displayed and allowing an operator to recognize the correspondence between the original and the copy density. CONSTITUTION:An optical sensor 15 is provided on a blocker of a lens 8 as the sensor which detects the original density during dummy scanning before the copy scan cycle for the original at an automatic copy density adjustment time. The optical sensor 15 converts the quantity of light to a voltage, and the photoelectric conversion output is given to an A/D converter 17 through an interface 16 and is converted to a digital signal and is given to a central processing unit CPU18 as data indicating the original density. The CPU18 gives a control signal to a developing bias control circuit 19 of a developing device 11 to adjust automatically the copy density in accordance with the original density detected beforehand by dummy scanning. A control signal is given to a display device 20 to display the copy density corresponding to the original density, and the operator recognizes the correspondence between the original and the copy density. |
