Patent ID: 8447212
Filing Date: 2013-05-21
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: plural latent image carriers configured to carry latent images; plural developing units configured to develop the latent images on the latent image carriers; an endless belt member; a drive unit configured to supply a rotating drive force to the endless belt member so as to move the endless belt member in an endless manner; a first detecting unit configured to detect a rotating speed of the drive unit; a second detecting unit, provided on a driven unit, configured to detect an endless transport speed variation of the endless belt member due to a diameter change in the drive unit caused by temperature change; and a control unit configured to perform a drive control operation for controlling the rotating speed of the drive unit based on a first detection signal from the first detecting unit or a second detection signal from the second detecting unit selectively depending on a selection condition, wherein the drive unit supplies the rotating drive force to at least one of the plural latent image carriers in addition to the endless belt member, and wherein the control unit is configured to, upon selection of the first detection signal in accordance with the selection condition, correct the rotating speed of the drive unit using the second detection signal such that an average value of the endless transport speed of the endless belt member approaches a target average value.