Patent ID: 9002245
Filing Date: 2015-04-07
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a movable image bearing member; an image forming unit configured to form a toner image on the image bearing member; a pre-transfer charging member configured to charge the toner image of the image bearing member, facing the image bearing member on a downstream side of the image forming unit in a movement direction of the image bearing member; a power supply configured to apply a voltage to the pre-transfer charging member; and a transfer member configured to form a transfer nip for transferring the toner image of the image bearing member to a recording material by pressing the image bearing member on a downstream side of the pre-transfer charging member in the movement direction of the image bearing member; and an execution unit configured to execute a first mode when a toner image is to be printed on a first side of the recording material, and execute a second mode when a toner image is to be printed on a second side of the recording material, wherein the execution unit sets a voltage of the power supply applied to the pre-transfer charging member as a first voltage in a period during which at least a specific region passes through a position facing the pre-transfer charging member and setting a voltage of the power supply applied to the pre-transfer charging member as a second voltage whose absolute value is lower than that of the first voltage after a second position of the image bearing member passes through the position facing the pre-transfer charging member in the first mode, and the execution unit sets a voltage applied to the pre-transfer charging member as the second voltage without switching the voltage at the second position in the second mode, and wherein a first position is a position of the image bearing member on an upstream side in the movement direction of the image bearing member, apart by a length corresponding to the transfer nip length from a position of the image bearing member overlapping with a leading edge of the recording material at the transfer nip, and the second position is a position on an upstream side at a predetermined distance which is shorter than a length of the recording material, from the first position, and the specific region is a region of the image bearing member between the first position and the second position.