Image forming apparatus

摘要

A controller controls a voltage to be applied to the transfer member when there is a recording material having a predetermined largest width at a secondary-transfer position, so that a constant-voltage element maintains a predetermined voltage, whereby it is possible to prevent transfer defect due to short of a primary-transfer electric field at a primary-transfer portion when a toner image is secondary-transferred onto the recording material.

主权项

1. An image forming apparatus comprising:
an image bearing member configured to bear a toner image; an intermediary transfer member configured to carry the toner image primary-transferred from the image bearing member at a primary-transfer position; a transfer member, provided contactable to an outer peripheral surface of the intermediary transfer member, configured to secondary-transfer the toner image from the intermediary transfer member onto a recording material at a secondary-transfer position; a constant-voltage element, electrically connected between the intermediary transfer member and a ground potential, configured to maintain a predetermined voltage by passing of a current therethrough; a power source configured to form, by applying a voltage to the transfer member to pass the current through the constant-voltage element, both of a secondary-transfer electric field at the secondary-transfer position and a primary-transfer electric field at the primary-transfer position; and a controller configured to control a voltage to be applied to the transfer member by the power source when the toner image is secondary-transferred onto the recording material having a predetermined largest width with respect to a widthwise direction perpendicular to a feeding direction, so that the constant-voltage element maintains the predetermined voltage.