| 摘要 |
PROBLEM TO BE SOLVED: To suppress a deterioration in a photoreceptor in the vicinity of an electrifier, after an image forming operation is completed and a device is stopped as well and to form an image without an image blur and density unevenness by keeping the concn. of a nitrogen oxide in the vicinity of the surface of the photoreceptor a specific value or below, after an image forming device is stopped as well. SOLUTION: A chemiluminescence type nitrogen oxide sensor 6 is used and its detection signal is transmitted to an A/D converter 17 through an amplifier 16. Then, a computer 18 decides the total current required to rotate a ventilating fan 15, from a concentration signal from the sensor 6. Then, output to the motor 14 of the ventilating fan 15 is attained through a D/A converter 19, to make the total current flow and execute exhaust from an exhaust duct 13. At this time, the ventilating fan 15 is controlled so that the concn. of the nitrogen oxide in the vicinity of the photoreceptor 4 after the image forming operation is completed and the rotation of the photoreceptor 4 is stopped becomes <=0.2ppm. Thus, the photoreceptive layer of the electrophotographic photoreceptor 4 in the vicinity of the electrifier is prevented from decomposing or deteriorating. |
