Patent ID: 9097587
Filing Date: 2015-08-04
Classification: G01J,G03G

Abstract:
1. An image forming apparatus comprising: an image forming unit configured to form a measurement image on a sheet; a measurement unit configured to radiate light on the measurement image via a transparent window, and measure the light reflected from the measurement image; a white reference plate of which a white level is measured by the measurement unit; a black member of which a black level is measured by the measurement unit; a calculation unit configured to calculate spectral reflectivity of the measurement image by correcting a measurement result of the measurement image measured by the measurement unit, based on the white level and the black level; and a determination unit configured to determine, based on a change in a measurement result of the white reference plate and a change in a measurement result of the black member measured by the measurement unit, whether the white reference plate, the black member, or the transparent window is dirty, wherein the determination unit determines that the transparent window is dirty, in a case where it has not been determined that the black member is dirty in a previous determination result, and a measurement result of the white reference plate measured by the measurement unit has changed from a prescribed value by at least a predetermined value, and a measurement result of the black member has changed from an initial value of the measurement result by at least a predetermined value.