Image forming apparatus having a toner carrying member

Abstract

The difference between the light reception output signals representing the amounts of regularly and irregularly reflected light as measured, with optical detecting means that can measure the amount of regularly and irregularly reflected light simultaneously, when no toner is adhered to a transfer belt is set as a reference value, a corrected output value is calculated by correcting, based on the reference value, the difference between the light reception output signals representing the amounts of regularly and irregularly reflected light as measured when a toner image is formed, and the amount of toner adhered to the transfer belt is calculated based on the corrected output value. With transfer belts of different colors, if their surface gloss is equal to or lower than a predetermined value, the relationship between the coverage ratio and the toner adhesion amount remains approximately identical. Thus, when a transfer belt whose initial surface gloss is equal to or lower than 20 at a measurement angle of 60 degrees, the amount of toner adhered can be measured precisely until the expiration of the warranted use period of the belt.

Dependencies are inferred from the claim text.