Patent ID: 7877031
Filing Date: 2011-01-25
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image carrier adapted to be formed with an electrostatic latent image; a developing unit adapted to develop the electrostatic latent image formed on said image carrier using a developer including toner; a detection unit which has a light emitting unit adapted to irradiate light onto the developer in said developing unit and a light receiving unit adapted to receive light reflected by said developer, said detection unit being adapted to output a signal corresponding to a toner density representing a toner ratio in the developer; and a determination unit adapted to determine whether or not a difference between a signal output from said detection unit when said detection unit detects a developer having a predetermined density and a signal output from said detection unit when said detection unit detects a reference member having a density different from the predetermined density falls within a predetermined range; wherein said detection unit is disposed so as to face a toner bearing member in said developing unit and adapted to detect the density of toner on said toner bearing member, the reference member is disposed on a surface of a shutter member which is irradiated by said light emitting unit, said shutter member is disposed between said toner bearing member and said detection unit to protect a light receiving surface of said light receiving unit, and said shutter member is openable and closeable.