Canon Kabushiki Kaisha

Mitsunari Ito

Yusuke Saito

Shiro Sakata

Masato Suzuki

Atsuya Takahashi

Kazushi Nishikata

Shotaro Yoshimura

Hisayuki Tomura

Kei Sawanaka

Akio Nemoto

The high-voltage output apparatus includes a voltage application part that applies a DC voltage to the charge member; a current detection part that detects a value of a current flowing in the image bearing member when the DC voltage is applied to the charge member; and a control part that calculates a plurality of discharge start voltages for the image bearing member, based on a plurality of current values detected by the current detection part as a result of the voltage application part applying a plurality of different DC voltages to the charge member, and controls the DC voltage applied to the charge member, using the plurality of calculated discharge start voltages. Consequently, a high-quality image can be formed by maintaining a potential on a photosensitive drum to be constant irrespective of the states of the circumstances and/or the drum layer thickness.

High-voltage output apparatus and image forming apparatus

The image forming apparatus calculates a surface voltage of an image bearing member based on a first charge start voltage, which is obtained when a first voltage application section applies a first DC voltage to a charge section, and a second charge start voltage, which is obtained when a second voltage application section applies a second DC voltage to the charge section. This allows a high-quality image to be formed irrespective of a change in circumstance or drum layer thickness.

Image forming apparatus

Sheets fed out from a sheet feeding portion, which is brought into pressure contact with the sheets by the upward movement of a sheet stacking portion to feed out the sheets, are separated and conveyed one by one while being upwardly curved. During the sheet feeding operation, the sheet stacking portion is sequentially moved up, and when the sheet feeding operation is completed, the sheet stacking portion is moved down. Further, a remaining amount indicating member moved with the upward movement of the sheet stacking portion to indicate the remaining amount of sheets is held at a position before the sheet stacking portion is moved down, by a holding mechanism, when the sheet feeding operation is completed and the sheet stacking portion is moved down.

Sheet feeding apparatus and image forming apparatus

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Numazu, Japan

Mitsunari Ito