Patent ID: 6658221
Filing Date: 2003-12-02
Classification: G03G

Abstract:
A toner quantity measuring apparatus for measuring the quantity of toner adhering to a belt-shaped image carrier which is stretched across a plurality of rollers, comprising:a sensor, including a light emitting element for irradiating light upon said belt-shaped image carrier, which receives light reflected by said belt-shaped image carrier and outputs a signal which corresponds to the quantity of the received light; and toner quantity deriving means which calculates the quantity of the toner adhering to said belt-shaped image carrier based on the output from said sensor, wherein said light emitting element is positioned to face one of said plurality of rollers across said belt-shaped image carrier, and irradiates light upon a wind area, out of a surface area of said belt-shaped image carrier, in which said belt-shaped image carrier rests on a sensor-facing roller which is positioned to face said light emitting element, wherein said belt-shaped image carrier rotates one round while said sensor-facing roller rotates two or more rounds, wherein said toner quantity deriving means samples the output from said sensor at predetermined sampling intervals while said belt-shaped image carrier rotates at least one round and calculates eccentric components of said rollers based on sampling output before forming a toner image, and wherein for calculation of the image density of said toner image on said belt-shaped image carrier, using said eccentric components, said toner quantity driving means corrects the output from said sensor which receives light reflected by said belt-shaped image carrier and calculates the image density of said toner image based on a correction value.