Patent ID: 8213815
Filing Date: 2012-07-03
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a sheet conveying path configured to convey a sheet from a paper feeding tray to a transfer position; an image transfer unit configured to transfer an image onto the sheet conveyed to the transfer position via the sheet conveying path; a dirty-spot-information acquiring unit that has light emitting elements which irradiate a predetermined region of the sheet and light receiving elements which receive the reflected light of light irradiated on the predetermined region from the light emitting elements, the dirty-spot-information acquiring unit configured to acquire information concerning a dirty spot on the sheet by calculating a reflectance of the predetermined region based on input and output of both the light emitting elements and the light receiving elements in a detection position located further on an upstream side in a conveying direction than the transfer position in the sheet conveying path; and a determining unit configured to determine that at least one dirty spot is present in the predetermined region, if the area from which the information concerning the dirty spot is acquired by the dirty-spot-information acquiring unit has an area equal to or larger than a predetermined area.