Canon Kabushiki Kaisha

Takehiro Uchiyama

Kenji Watanabe

Hiroshi Hagiwara

Tomohiro Nakamori

Hiromitsu Kumada

Takateru Ohkubo

Toshiaki Sako

Teruhiko Namiki

Atsuhiko Yamaguchi

Osamu Nagasaki

Kouji Yasukawa

Ken-ichi Iida

Hiroki Murata

Kenichi Iida

Takeshi Kawamura

An image forming apparatus includes a photosensitive section driven to rotate, a light emission unit configured to emit light to form electrostatic latent images on the photosensitive section, a process section configured to form images on the photosensitive section, a detection unit configured to detect an output generated via the process section when an electrostatic latent image for correction passes through a position facing the process section, and a control unit configured to execute a correction of a position of an electrostatic latent image in image formation based on a detection result from the detection unit.

Color image forming apparatus

The image forming apparatus includes process units that are closely arranged around respective photosensitive members and act on the photosensitive members, a light emission section that forms an electrostatic latent image for detection on the photosensitive member and a detection section that detects that the electrostatic latent image passes through a position facing the process unit, and a control section that performs misregistration correction control based on the detection result.

A power supply device generates an output voltage by driving a piezoelectric transformer using a frequency signal. The power supply device includes a comparison unit configured to compare an output voltage and a voltage setting signal that sets the output voltage, and a voltage control oscillation unit configured to generate the frequency signal to drive the piezoelectric transformer based on comparison results of the comparison unit. The voltage control oscillation unit generates the frequency signal within a range between the resonant frequency and a spurious resonant frequency closest to the resonant frequency.

Power supply device and image forming apparatus using the power supply device

A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, an output voltage control circuit which controls an output voltage from the piezoelectric transformer, and includes a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal. The power supply unit also includes a driving frequency supplying circuit which generates a driving frequency signal of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the driving frequency signal to the piezoelectric transformer. The time constant of the output voltage control circuit is longer than the time constant of the output voltage detecting circuit.

Power supply unit in image forming apparatus

An image forming apparatus including an AC high voltage power supply, a DC high voltage power supply, and a high voltage power supply apparatus, which outputs an output voltage at an output end by superposing an output of the AC high voltage power supply and an output of the DC high voltage power supply. The high voltage power supply apparatus has a positive peak detector detecting a positive peak of the voltage at an output end, and a negative peak detector detecting a negative peak of the voltage at an output end. An output voltage of at least one of the AC high voltage power supply and the DC high voltage power supply is controlled on the basis of the detection result of at least one of the positive peak detector and the negative peak detector. An output voltage of the AC high voltage power supply is controlled on the basis of the detection result of the positive peak detector, and an output voltage of the DC high voltage power supply is controlled on the basis of the detection result of the negative peak detector.

Image forming apparatus and high voltage power thereof

Growing community of inventors

Kawasaki, Japan

Takehiro Uchiyama