Image forming apparatus that control the reflected light detected by an optical scanner in response to a gradation area percentage of a toner patch

摘要

An image forming apparatus that prepares a toner patch including a predetermined gradation area percentage on an image support to detect a developing concentration. An optical sensor detects reflected light from the background of the image support and reflected light from the toner patch prepared on the image support. The reflected light detected by the optical sensor is then controlled in response to the gradation area percentage of the prepared toner patch.