Ricoh Company, Ltd.

Koji Kiryu

Masahiro Ashikawa

Masashi Kasamai

Kanji Ubukata

Jumpei Yamaguchi

Nagisa Nakamura

Hiroyuki Iwasaki

Hiroaki Takagi

Takahisa Koike

Yuusuke Ishizaki

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

A belt controller, an image forming apparatus, a belt controlling method, and a recording medium storing an image forming control program adjust a position of a belt. Each of the belt controller, the image forming apparatus, the belt controlling method, and the recording medium storing an image forming control program detects a position of the belt and transmits a position detection signal, determines whether a degree of misalignment of the belt is equal to or greater than a specified threshold before the belt starts moving based on the position detection signal, presses the belt to reduce the degree of misalignment of the belt when the degree of misalignment of the belt is equal to or greater than the specified threshold, and performs feedback control to adjust the position of the belt according to the degree of misalignment of the belt after pressing the belt.

Belt controller, image forming apparatus, image forming method, and recording medium storing image forming control program

Disclosed is an image forming device that forms toner images on corresponding photosensitive bodies, and performs primary transfers for transferring the toner images on the corresponding photosensitive bodies onto an intermediate transfer body and performs a secondary transfer for transferring the toner images from the intermediate transfer body onto a recording medium. The image forming device includes a position detection unit that detects a position of the intermediate transfer body; a position control unit that controls movement of the intermediate transfer body; a speed determination unit that determines a speed of the intermediate transfer body; and an image forming control unit. The image forming control unit causes the image forming device to form the toner images, to perform primary transfers or to perform a secondary transfer, when the intermediate transfer body is moving at a constant speed.

Image forming device, image forming method, and image forming system for controlling a position of an intermediate transfer body in a width direction

A belt drive apparatus is equipped with an endless belt rotationally movable by being supported by a plurality of rollers. A moving speed signal output part outputs a signal based on a rotational movement of the endless belt. A width direction position signal output part outputs a position signal for which its value changes in response to a position of the endless belt in a direction of width of the endless belt. A width direction position control part controls a position of the endless belt in the direction of width of the endless belt. A process execution part performs a predetermined process using the signal output from the moving speed output part based on the position signal output from the width direction position signal output part.

Belt drive apparatus for correcting belt position in direction of width

An image forming device has a full-color image formation mode to form a color image using color photoconductor drums and a monochrome image formation mode to form a monochrome image using a photoconductor drum. In the image forming device, a driving unit drives rotation of an intermediate transfer belt or a transfer transport belt. A control unit changes rotational speeds of the color photoconductors in a transition from the full-color image formation mode to the monochrome image formation mode to make a torque to the driving unit in the full-color image formation mode equal to a torque to the driving unit in the monochrome image formation mode. A separator unit separates the color photoconductors from the intermediate transfer belt or the transfer transport belt after the rotational speeds of the color photoconductors are changed by the control unit.

Image forming device including color photoconductor drums, photoconductor drum drive controlling method for controlling color photoconductor drums, and computer-readable recording medium

A disclosed moving body controlling device includes a first moving body driven by a first motor that is controlled by a first control unit, a second moving body driven by a second motor that is controlled by a second control unit and affecting movement of the first moving body, a memory unit storing a relationship between the second motor rotational speed and an indicating value for driving the first and second motors when the second control unit changes the second motor rotational speed while the first control unit controls a first motor rotational speed to cause a first rotational body surface speed to be a predetermined speed in a mode of setting a second motor target rotational speed, whereby a reference point at which the surface speed starts to exceed the predetermined speed is detected, and based on the reference point the second motor target rotational speed is set.

Moving body controlling device, intermediate transferring device, and image forming apparatus having the same

A motor driving device includes an amplifying unit, a noise removing unit, an analog-to-digital converter, a calculating unit, and a motor driving unit. The amplifying unit amplifies an analog frequency signal corresponding to a rotation speed of a direct-current brushless motor. The noise removing unit removes noise from the analog frequency signal after amplification. The analog-to-digital converter converts the analog frequency signal from which noise is removed to a digital frequency signal. The calculating unit calculates a current control amount with respect to each phase of the direct-current brushless motor based on the digital frequency signal. The motor driving unit drives the direct-current brushless motor at a specified speed based on the current control amount.

Motor driving device, image forming apparatus, and motor driving method

A drive control unit for controlling speeds of driving parts based on a target speed, includes a detecting part to detect speed fluctuations of each of the driving parts when the speeds of the driving parts are controlled based on a common target speed, a storage part to store speed fluctuation profiles of each of the driving parts created based on the detected speed fluctuations, an extracting part to extract a speed fluctuation profile having a largest amplitude of the speed fluctuation profiles stores in the storage part, a calculating part to calculate difference profiles of the driving parts, corresponding to differences between the extracted speed fluctuation profile and the speed fluctuation profiles of each of the driving parts, a setting part to set the difference profiles of the driving parts as new target speeds of the driving parts, and a control part to control the speeds of the driving parts based on the new target speeds.

Drive control unit, drive control method and image forming apparatus

The color offset is reduced with a simple system by relative removal of speed variation components between drums of a tandem color image forming apparatus. Assuming that the speed variation of a magenta photosensitive drum is the largest, the speed variation components of various colors are subtracted from the speed variation component relating to magenta, and the results are added to the respective speed target values. The rotational speed differences of the photosensitive drums of various colors are eliminated by applying the same speed variation component as in the case of magenta to the rotational speed of the photosensitive drums of various colors other than magenta. Phase correction is performed with respect to the phase differences produced by the fact that the distance between drums of various colors is different from the drum peripheral length. Since the phase difference of the photosensitive drums is then zero at the transfer positions of various colors, the effect of speed variation is prevented from appearing in the image as color offset.

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Kanagawa, Japan

Koji Kiryu