Ricoh Company, Ltd.

Masashi Kasamai

Masahiro Ashikawa

Koji Kiryu

Nagisa Nakamura

Kanji Ubukata

Jumpei Yamaguchi

Yoshihiro Takahashi

Hiroaki Takagi

Takahisa Koike

Yusuke Ishizaki

Kohhei Yamaguchi

A control device includes circuitry. The circuitry detects density unevenness of a toner image occurring according to a rotation cycle of a plurality of image bearers based on rotation phases and toner image density of the plurality of image bearers, controls rotation phases and rotation speeds of the plurality of image bearers, corrects the rotation phases and the rotation speeds of the plurality of image bearers, controls the rotation speeds of at least two of the plurality of image bearers to be a specified rotation speed, and starts a detection operation of the rotation phases of the plurality of image bearers after a difference between each of the rotation speeds of the at least two of the plurality of image bearers and the specified rotation speed falls within a specified range.

Control device, image forming apparatus, image forming method, and storage medium

An image forming apparatus includes image bearers, motors, a reference position detector, and processing circuitry. The circuitry senses a density of a toner image on each bearer; forms an image pattern and senses, based on a detection result of the detector and a sensing result of the density, density unevenness in a rotation cycle and a phase of the density unevenness with respect to a rotational position reference of each bearer; calculates a target phase based on the phase sensed; calculates a relative phase difference based on a rotational position and the target phase of each bearer; selects, as a reference image bearer, an image bearer having a minimum phase correction value, based on a calculation result of the difference; and controls the rotational position of each of the other image bearers with respect to the reference image bearer to the phase correction value, with the motors being driven.

Image forming apparatus in which rotational position of image bearer is controlled to reduce density unevenness

A transfer device includes a plurality of photoconductors, a belt, a plurality of primary transfer rollers and control circuitry. The plurality of primary transfer rollers is disposed for the plurality of photoconductors, respectively. The plurality of primary transfer rollers brings the belt into contact with or separate the belt from the plurality of photoconductors. The control circuitry causes at least one of the plurality of primary transfer rollers to press against a corresponding at least one of the plurality of photoconductors to shift a printing mode.

Transfer device and image forming apparatus including photoconductors, a belt, and primary transfer rollers

An image forming apparatus includes a plurality of image bearers, a plurality of rotation reference position detectors, and circuitry. Each of the plurality of rotation reference position detectors faces a corresponding image bearer of the plurality of image bearers to detect a rotation reference position of the corresponding image bearer. The circuitry performs, before an operation of rotating the plurality of image bearers, alignment control based on a result of detection performed by the plurality of rotation reference position detectors. The alignment control is control of driving of the plurality of image bearers to acquire a given relationship between the respective rotation reference positions of the plurality of image bearers. The circuitry determines whether to perform the alignment control based on whether the operation of rotating the plurality of image bearers is a function maintenance related operation.

Image forming apparatus

An electronic circuit includes a first consumption part, at least one second consumption part, and a current mirror circuit. The first consumption part passes a current to consume electricity when a voltage exceeding a first voltage is applied. At least one second consumption part is disposed in parallel with the first consumption part and passes a current to consume electricity. The current mirror circuit passes, to the second consumption part, a current corresponding to a current that flows through the first consumption part.

Electronic circuit, protective device, and image forming apparatus

A medium conveying apparatus includes a conveying status detecting unit configured to determine a conveyance status of a medium based on a driving torque of a driving unit, wherein the conveying unit is configured to convey the medium at a reference speed, the reference speed being faster than the upstream conveying unit at least when the medium is conveyed from the upstream conveying unit, and the reference speed being slower than the downstream conveying unit at least when the medium is conveyed to the downstream conveying unit, and wherein the conveyance status of the medium is detected by the comparison of a prescribed reference torque to the driving torque of the driving unit at least when the medium is conveyed between the upstream conveying unit and the conveying unit or when the medium is conveyed between the conveying unit and the downstream conveying unit.

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Kanagawa, Japan

Masashi Kasamai