An image forming apparatus comprising:
- an image bearing member configured to bear a toner image;
- an intermediate transfer belt that is rotatable, endless, and onto which the toner image is to be transferred from the image bearing member;
- a primary transfer member configured to primarily transfer the toner image from the image bearing member onto the intermediate transfer belt by supplying a primary transfer current to the intermediate transfer belt at a primary transfer portion;
- a first power source configured to apply a voltage to the primary transfer member;
- a first detecting unit configured to detect a current supplied from the first power source;
- a secondary transfer member configured to secondarily transfer the toner image from the intermediate transfer belt onto a recording material by supplying a secondary transfer current to the intermediate transfer belt at a secondary transfer portion;
- a second power source configured to apply a voltage to the secondary transfer member;
- a second detecting unit configured to detect a current supplied from the second power source;
- a discharge member configured to supply a discharge current to the intermediate transfer belt at a discharge portion downstream of the secondary transfer portion and upstream of the primary transfer portion in a rotation direction of the intermediate transfer belt;
- a third power source configured to supply the discharge current;
- and
- a control unit configured to control the third power source,
- wherein, during execution of a print job of continuous image formation in which the toner image is continuously transferred onto a first recording material and a second recording material following the first recording material, the control unit controls the third power source such that the discharge current is subjected to constant current control based on a detection result detected by the first detecting unit during the print job and a detection result detected by the second detecting unit during the print job, and
- wherein, when changing the discharge current from a first discharge current to a second discharge current, the control unit controls the third power source such that, after an image forming region of a first image to be transferred onto the first recording material passes through the primary transfer portion, a trailing edge of a first discharge current supply region on the intermediate transfer belt, to which the first discharge current is supplied, initially passes through the primary transfer portion, and also controls the third power source such that, before an image forming region of a second image to be transferred onto the second recording material passes through the primary transfer portion, a leading edge of a second discharge current supply region on the intermediate transfer belt, to which the second discharge current is supplied, initially passes through the primary transfer portion.