| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of properly suppressing a charging processing condition of a photosensitive member at each of image forming speeds when the image forming speed is changed, and also suppressing the lowering in image productivity due to a control operation of the charging processing condition varying depending on the change in the image forming speed. SOLUTION: The image forming apparatus has: a rotatable photosensitive member; a charging member for electrically charging the photosensitive member; applying means for applying a charging bias in the form of a DC voltage biased with an AC voltage to the charging member; toner image forming means for forming a toner image on the photosensitive member charged by the charging member; setting means for setting a frequency of the first charging bias at the first frequency in the first mode in which the photosensitive member is rotated at the first speed to effect image formation and for setting a frequency of the second charging bias at the second frequency being different from the first frequency in the second mode in which the photosensitive member is rotated at the second speed slower than the first speed to effect image formation; detection means for detecting a current passing between the charging member and the photosensitive member during application of a test bias to the charging member; and adjusting means for adjusting the second charging bias on the basis of an output of the detection means when the photosensitive member is rotated at the first speed and a test bias having the second frequency is applied to the charging member when forming an image by switching from the first mode to the second mode. COPYRIGHT: (C)2010,JPO&INPIT |
