Patent ID: 9256166
Filing Date: 2016-02-09
CPC Classification: G03G

Claim Text:
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 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 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 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; a detecting portion configured to detect the current passing through the transfer member; an executing portion configured to execute a test mode in which when no recording material exists at the secondary-transfer position, a test voltage is applied to the transfer member by the power source to detect the current by the detecting portion; and a controller configured to control, on the basis of the current detected by the detecting portion in the test mode, a voltage to be applied to the transfer member by the power source when the recording material exists at the secondary-transfer position, wherein the controller controls the test voltage applied by the power source so that the constant-voltage element maintains the predetermined voltage in a period of the test mode.