| 摘要 |
PURPOSE:To simplify an operation by providing separately circuits for changing over a mode forming a positive image from a negative or positive original and increasing or decreasing developing bias and making the circuits adjustable by common adjusting means. CONSTITUTION:A mu computer 20 having a CPU, ROM, RAM and I/O is inputted with the signal for obtaining the positive (P) image from the negative (N) original or the P image from the P original from a detecting circuit 22 and controls a driving circuit 21. Electricity is conducted to a relay coil 4 via an inverter IN by the output signal out of the computer 20 to drive a relay RY which changes over a contact C to a contact NC or NO and connects the same to resistance circuits R3, VR2, R4 or R1, VR1, R2. The variable resistors VR1, RV2 are controlled to input a voltage signal VREM to a driving circuit 21 which feeds driving voltages HV1, HV2, HAC to electrostatic chargers 2, 5 as well as a sleeve 4a and a blade 4b. The VR1, VR2 are thus cooperatively operated in either of the N P or P P mode, by which the adjustment is made easy. |
