Patent ID: 9042752
Filing Date: 2015-05-26
Classification: G03G

Abstract:
1. An image forming apparatus configured to form an image on a recording material, the image forming apparatus comprising: an image bearing member; a charging device configured to contact the image bearing member; a power source capable of outputting a plurality of alternating-current voltages differing in peak-to-peak voltage and configured to apply a voltage obtained by superimposing an alternating-current voltage and a direct-current voltage on each other to the charging device; and a control unit configured to execute an initial rotating operation to rotate the image bearing member in a first speed before the image bearing member becomes a ready state in which rotation of the image bearing member is stopped, and execute a preparatory rotating operation to rotate the image bearing member in a same speed as a speed during image formation after the image forming apparatus is released from the ready state and before the image forming apparatus starts image formation, wherein the control unit performs first control during said initial rotating operation to cause the power source to apply at least one alternating-current voltage of the plurality of alternating-current voltages to the charging device and to detect a value of current flowing through the image bearing member, wherein when the image bearing member is to be rotated at a second speed higher than the first speed during the preparatory rotating operation, the control unit performs second control during the preparatory rotating operation to cause the power source to apply at least one alternating-current voltage to the charging device, and, to detect a value of current flowing through the image bearing member, and to determine a peak-to-peak voltage of an alternating-current voltage to be applied to the charging device at the time of image formation based on the detected current value in the second control, wherein a peak-to-peak voltage of an alternating-current voltage applied to the charging device in the second control is determined according to the current value detected in the first control.