| 摘要 |
PURPOSE:To always form an exact image by detecting a load current or voltage of an electrostatic charger, and controlling a high-voltage generating means for driving the charger and detecting its abnormality in accordance with the detected output. CONSTITUTION:Control voltage produced from a primary high voltage control circuit 18 is fed to one terminal of the primary coil 31 of the transformer 30 of a primary high voltage generator 21, and voltage generated with the secondary coil 32 is rectified and smoothed and applied to the primary charger 2 of an image forming device. The other end of the coil 32 is grounded through a resistor R1, and voltage Vf across the resistor R1 is fed back to the circuit 18 and an A/D conversion circuit 9. The circuit 18 controls a circuit 21 in accordance with data sent from a microcomputer 15 through a D/A circuit 16, and the voltage Vf. The output voltage Va' of the circuit 16 and that Vc of the circuit 18 are fed back through the circuit 9 to the computer 15. It observes voltages Vf, Vc to detect abnormality of the circuit 21 and displays it, and it can change display of abnormality and control of the circuit 21 to always execute exact image formation.
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