Image forming apparatus

摘要

The present invention relates to an image forming apparatus that forms an image by consecutively superposing toner images that have been formed on a plurality of photosensitive drums, on an intermediate transfer member or a transfer medium. The image forming apparatus is made compact and operates at a low cost. Since a current supply member supplies a current in a rotational direction of an intermediate transfer belt, multiple first transfer portions do not need corresponding voltage sources. Even in the case where a charging member supplies a current, the potential of the intermediate transfer belt is maintained at a predetermined potential by a constant-voltage element connected to support rollers.

主权项

1. An image forming apparatus comprising:
a plurality of image bearing members that each bear a toner image; a rotational endless intermediate transfer belt configured to second-transfer the toner image first-transferred from each of the plurality of image bearing members to a transfer medium; a plurality of support rollers that support the intermediate transfer belt; a current supply member that comes into contact with the intermediate transfer belt; a transfer power source configured to apply a voltage to the current supply member in order for the toner image to be second-transferred from the intermediate transfer belt to the transfer medium; a charging member that charges a residual toner remaining on the intermediate transfer belt without being second-transferred to the transfer medium; and a charging power source configured to apply a voltage to the charging member, wherein the intermediate transfer belt is a conductive belt that allows a current to flow to the plurality of image bearing members via the intermediate transfer belt from a portion that is in contact with the current supply member, in a rotational direction of the intermediate transfer belt, wherein the plurality of support rollers are connected to a constant-voltage element that maintains a surface potential of the intermediate transfer belt at a predetermined potential, and wherein, when a voltage is applied from the transfer power source to the current supply member, a current is allowed to flow from the current supply member to the plurality of image bearing members via the intermediate transfer belt, and thus the toner images are first-transferred from the plurality of image bearing members to the intermediate transfer belt.