IMAGE FORMING APPARATUS Russian patent published in 2014 - IPC G03G15/00 

FIELD: physics.

SUBSTANCE: image forming apparatus comprises an image bearing element, a developing device for developing an electrostatic latent image on the surface of said image bearing element. Said developing device includes a developer transfer element for moving developer, which includes nonmagnetic toner and a magnetic carrier, to a developing position in which the developer transfer element is located opposite said image bearing element, detection means for detecting information correlating to the amount of charge of the toner of the developer in said developing device, and a controller operating during the image formation period, wherein images are continuously formed on a plurality of recording materials. The image formation period includes a first period and a second period, the first period corresponding to the interval between the time when recording material and the next recording material are subjected to image formation, and the duration of the first period being not less than a predetermined period. The controller is configured to stop or slow down movement of the developer transfer element during the first period, the reduced speed being at least the speed of the developer transfer element during the second period, wherein the image region corresponding to the recording material passes through the developing position. The controller is configured to control, based on the detection result of said detection means, said developing device such that the potential difference between a portion without an image of said image bearing element and bias voltage applied to the developer transfer element in the first period falls with fall in the detected amount of charge of toner, through which toner tends to be deposited less on the developer transfer element, with a lower amount of charge of toner in the first period than in the second period.

EFFECT: providing an image forming apparatus which is capable of eliminating image defects independent of the state of use of the developer.

6 cl, 27 dwg