Patent ID: 8068756
Filing Date: 2011-11-29
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image forming unit configured to form an image on an image carrier; a transfer unit configured to transfer the image formed on the image carrier onto a transfer medium; a voltage applying unit configured to apply a voltage to said transfer unit; a current detection unit configured to detect a current that flows through said transfer unit when said voltage applying unit applies the voltage; and a control unit configured to control said voltage applying unit based on a detection result of said current detection unit, wherein when a plurality of images are to be formed continuously, said control unit controls said voltage applying unit to apply a voltage of a first value to said transfer unit during a first period in which a first non-image-forming area where no image is formed is located on said transfer unit, and controls said voltage applying unit to apply a voltage of a second value to said transfer unit during a second period in which a second non-image-forming area is located on said transfer unit, and an image-forming area is existed between the first non-image-forming area and the second non-image-forming area, wherein said control unit determines a voltage value of a voltage to be applied from said voltage applying unit to said transfer unit on the image-forming area where an image is formed is located on said transfer unit, based on the voltage of the first value, the voltage of the second value, and the detection results of said current detection unit during the first period and the second period, and wherein said control unit determines an impedance characteristic of said transfer unit based on a first current value detected by said current detection unit upon applying the voltage of the first value to said transfer unit, and a second current value detected by said current detection unit upon applying the voltage of the second value to said transfer unit, and determines a voltage value, at which a current of a predetermined value flows through said transfer unit, in accordance with the impedance characteristic.