Ricoh Company, Ltd.

Rioch Company, Limited

Yusuke Shimbo

Kouji Ishigaki

Mayumi Yoshida

A scorotron charging device applicable to electrophotographic image forming equipment and having a main charger with discharge wires and a grid and applying voltages to the wires and the grid by respective power sources. The two power sources are controlled by the same control signal. In response to the control signal, a voltage starts being applied to the grid before a voltage is applied to said wires and ends being applied to the grid after the voltage application to the wires has ended. This allows the charge potential of a photoconductive element to rise and fall rapidly.

Charging device for electrophotographic equipment

A device incorporated in image forming equipment for adjusting the output of an image density sensor which optically senses the density of a toner image formed on a photoconductive element and representative of a reference pattern. The density sensor is made up of a light emitting element and a light-sensitive element. Thresholds divide an output range wherein the output characteristic of the sensor does not change into a plurality of subranges having the optimal output associated with the background of the photoconductive element as the center value. The sensor senses the background of the photoconductive element at predetermined intervals. Whether or not to adjust the output of the sensor is determined on the combination of the subrange where the resulting output of the sensor lies and the number of times that the former lies in the latter. The sensor output, i.e., a PWM (Pulse Width Modulation) duty to be fed to the light emitting element is changed to control the adjusted output associated with the background to the optimal value.

Growing community of inventors

Tokyo, Japan

Yusuke Shimbo