Konica Minolta, Inc.

Morio Osada

Junji Murauchi

Tomohisa Yoshida

Masanori Kawada

Kazuki Kobori

Tomo Kitada

Tetsuo Sano

An image forming apparatus includes photoconductors. Electrifiers uniformly electrify surfaces of the photoconductors. A power source applies an electrifying voltage to the electrifiers. A current measurer measures alternating current caused to flow by application of AC voltage by the power source. A controller calculates discharge starting voltage. Environment detectors detect an environment inside of the apparatus. The controller operates the current measurer at each predetermined timing to acquire the discharge starting voltage. When acquiring the discharge starting voltage, the controller changes peak-to-peak voltage at pre-discharge voltage and at post-discharge voltage. The current measurer measures alternating current at measurement points of each of the pre-discharge and post-discharge voltages. The controller calculates a voltage value at an intersection of a first line and a second line. After acquiring the discharge starting voltage, the controller calculates environment-correction discharge starting voltage, and sets electrification voltage based on the calculated voltage.

Image forming apparatus for setting an electrification voltage

An image forming apparatus includes a photoreceptor rotatable about an axis, and having a surface with a photosensitive layer abraded during use, a charging unit configured to charge the surface of the photoreceptor, an exposure unit configured to form an electrostatic latent image on the surface of the photoreceptor, a developing unit configured to form a toner image on the surface of the photoreceptor, and a control unit configured to obtain a film thickness of the photosensitive layer for each of a plurality of different positions in a direction of a rotation axis of the photoreceptor, and perform abrasion operation at a first or second position of the plurality of positions, when a difference in film thickness between the first position and the second position exceeds a predetermined reference value.

Image forming apparatus

An image forming apparatus including: a contact charging unit that is in contact with a photoreceptor and electrically charges the photoreceptor by causing electric discharge; a bias applying unit that applies an AC bias to the contact charging unit; and a superposing unit that superposes a DC bias onto the AC bias, the DC bias having a same polarity as a charge polarity of the photoreceptor. The AC bias has a same waveform as a rectangular wave bias during a period in which an absolute value of the AC bias is smaller than an absolute value of a predetermined boundary voltage, and the absolute value of the AC bias increases at a slower rate than an absolute value of the rectangular wave bias during a period in which the absolute value of the AC bias is equal to or greater than an absolute value of a discharge start voltage.

Growing community of inventors

Toyokawa, Japan

Morio Osada