Patent ID: 7853179
Filing Date: 2010-12-14
Classification: G03G

Abstract:
1. An image forming apparatus comprising a controller and a developing apparatus, the developing apparatus including: a plurality of developer units each having a toner storage that stores toner therein and a developing chamber into which the toner is supplied from the toner storage; a rotary rack that accommodates the developer units radially therein; and a driver operable to drive the rotary rack to move each of the developer units to a developing position at which developing thereby is performed, wherein when each of the developer units is within a predetermined range of rotation, the toner stored in the toner storage thereof is supplied to the developing chamber by falling through a toner supply opening thereof, and the controller including: a judgment part operable to make a judgment whether or not an amount of toner in a developing chamber of a developer unit for the single color is equal to or less than a predetermined amount during execution of a monochrome image forming job which forms an image using toner of a single color, wherein the controller, if the judgment is affirmative, (i) suspends the execution, (ii) causes the driver to rotate the rotary rack in a manner that the developer unit for the single color (a) either stops within the predetermined range of rotation for a predetermined period of time, or passes through the predetermined range of rotation at a lower speed than when outside the predetermined range, and (b) moves to the developing position, and (iii) resumes the execution, wherein the developing apparatus further includes a storage toner amount detector operable to detect an amount of toner remaining in a toner storage of the developer unit for the single color, and the controller refers to a detection signal output from the storage toner amount detector and performs a control in a manner such that the developer unit for the single color stops in the predetermined range of rotation for a longer period of time as the amount of toner remaining in the toner storage decreases.