Ricoh Company, Ltd.

The Furukawa Electric Co., Ltd.

Toshiyuki Andoh

Hiromichi Matsuda

Kazuhiko Kobayashi

Takashi Hashimoto

Takashi Hodoshima

Seiji Hoshino

Hidetaka Noguchi

Yuji Matsuda

Tatsuhiko Oikawa

Nobuto Yokokawa

Makoto Komatsu

Masato Yokoyama

Yohei Miura

Tadashi Shinohara

Jun Hosokawa

Yoshihiro Sakai

Toshiyuki Takahashi

Takuya Murata

Hiroshi Okamura

Yuichiro Ueda

Takuya Uehara

Yuuji Matsuda

Yohhei Miura

Ryoji Imai

Hiroshi Koide

Joh Ebara

Tetsuo Watanabe

Koichi Kudo

Ryuuichi Mimbu

Yasuhisa Ehara

Katsuya Kawagoe

Junya Takigawa

Hiroki Ohkubo

Takuroh Kamiya

Masanori Saitoh

Noriaki Funamoto

Toyokazu Satomi

Hiroyuki Yamasaki

Minoru Takahashi

Seiichi Handa

Masahiko Kato

Takahiro Kamekura

Yasumori Nagahara

Satoru Tao

Kojiro Inamori

Yuichi Hirose

Noritaka Masuda

Mikio Kamoshita

Yuji Uozaki

Masata Yokoyama

Toshiyuki Yakahashi

Tomiko Takahashi

An image formation apparatus includes an image carrier; a driving source generating a driving force for the image carrier; a drive transmission unit; a driving control unit controlling the driving source; an image formation unit forming an image on a surface of the image carrier; a transfer nip between a transfer member and the surface of the image carrier; a driving-force exerting unit exerting a driving force on any one of the image carrier and a first drive transmission member on a drive transmission path, and a specific drive transmission member imparting weakest spring characteristics among drive transmission members to a drive transmission system; a detecting unit detecting an estimation parameter used in estimating a driving-load-torque variation amount of the image carrier; a torque-variation-amount estimation unit; and a driving-force control unit controlling the driving force to cancel the driving-load-torque variation.

Image formation apparatus, driving control method, and computer program product

A load torque variation upon entry or exit of a sheet into a nipping portion is reduced while a nipping force necessary for image formation is provided. An image transfer apparatus, an image fixing apparatus, or a registration apparatus comprises an opposite roller, a transfer roller, and a compression spring for pressing the opposite roller onto the transfer roller. A sheet of transfer material is transported into a nipping portion between the opposite roller and the transfer roller, where an image on the opposite roller is transferred to the transfer material. The apparatus includes a retaining unit configured to retain a certain distance between the first rotating body and the second rotating body as long as the thickness of the transfer material that passes through the nipping portion remains the same.

Image transfer apparatus, image fixing apparatus, and registration apparatus which prevent a load torque variation upon entry or exit of a sheet into a nipping portion

In an image forming apparatus, a distance adjusting unit adjusts an inter-unit distance between a contact unit and an image carrier by moving the image carrier or the contact unit by applying an opposing force to the image carrier or the contact unit against a biasing force applied by a biasing unit based on thickness information of a recording sheet acquired by a thickness-information acquiring unit and data indicating a relationship between the thickness information and an inter-unit distance change amount stored in a data storage unit.

Image forming apparatus

A transfer roller lies opposite to a supporting roller across an image carrying belt and abuts against the outer surface of the image carrying belt to form a transfer nip. A driving force transmission unit transmits driving force from a driving source to a driving roller. A drive control unit performs drive control of the driving source. A feedforward control unit performs feedforward control on the driving source via the drive control unit. An entry detecting unit detects entry of a sheet in the transfer nip. The feedforward control unit considers an entry detection signal output by the entry sensor as a trigger for performing feedforward control after a predetermined time.

Transfer device and image forming apparatus

A sheet conveying device includes a pair of upstream rollers and a pair of downstream rollers each including a drive roller and a driven roller, a calculating unit, and a control unit. The upstream rollers include a measuring unit that obtains speed information of the upstream rollers. The calculating unit calculates a target value based on the speed information. The control unit controls the speed of the drive roller of the downstream rollers based on the target value.

Image forming apparatus and sheet conveying device having upstream and downstream rollers

An image-carrier driving unit drives an image carrier. An image forming unit forms an image on the image carrier. A moving-member driving unit drives a moving member that is movable towards and away from the image carrier. A detecting unit detects a position of the moving member at predetermined sampling times while the moving member is moving. A movement control unit performs a feedback control on the moving-member driving unit such that a detection result of the detecting unit follows a target value corresponding to each of the predetermined sampling times when the moving member moves while the image forming unit is forming the image on the image carrier.

Image forming apparatus for controlling movement of a moving member

An image forming device is disclosed that is able to enlarge a gap of a nipping portion with a simple and inexpensive structure, and able to reduce impact when a front end of a recording sheet runs into or a back end of the recording sheet passes through the nipping portion. The image forming device includes an image carrying unit, an image forming unit, a transfer unit, a conveyance unit, a determination unit that determines whether a thickness of the recording sheet is greater than a threshold value, and a cam member that rotates to enlarge or reduce the gap of the nipping portion between the image carrying unit and the transfer unit according to rotational positions of the cam member. When the thickness of the recording sheet is greater than the threshold, the cam member rotates so that the gap of the nipping portion is enlarged.

Image forming device

A belt drive control device includes: first and second detection devices which detect the angular displacement or velocity of a driven rotary member and the angular displacement or velocity of a drive rotary member, respectively; an extraction device which extracts, from the difference between the detection results of the first and second detection devices, the amplitude and phase of a variation component due to belt thickness variation; a control device which controls the rotation of the drive rotary member in accordance with the extracted amplitude and phase; first and second holding devices which hold the extracted amplitude and phase and normal ranges of the amplitude and phase, respectively; and first and second feedback devices which feed back the amplitude and phase to the rotation control, and performs feedback by using a substitution value for the amplitude or phase if the amplitude or phase is out of the normal range, respectively.

Belt drive control device, belt device, image forming apparatus, and belt drive control method

A driving apparatus includes a driving unit, a driven unit driven by the driving unit, a driving control unit configured to control the driving unit by performing feed-forward control based on feed-forward target data determined in advance to reduce a speed change of the driven unit. The speed change of the driven unit is expressed substantially as a positive half cycle of a sinusoidal waveform having an amplitude and a time duration, and the feed-forward target data is calculated from the amplitude and the time duration to represent a rectangular waveform approximating the positive half cycle of the sinusoidal waveform.

Driving apparatus and image forming apparatus

A fluctuation detecting unit detects a fluctuation of an endless belt generated when a sheet is brought into contact with a predetermined position of the endless belt at an upstream side in a conveying direction from a nip portion based on fluctuation information acquired by a fluctuation information acquiring unit. An entry timing estimating unit estimates entry timing of the sheet into the nip portion based on a detection of the fluctuation. A correction control unit corrects a speed fluctuation of the endless belt generated when the sheet enters the nip portion by performing a feedforward control of a first driving unit based on the entry timing.

Sheet conveying device and image forming apparatus

A second rotary member is arranged opposite to a first rotary member to form a nip between them. A driving unit drives the first rotary member. A sheet-width measuring unit measures a width of a sheet to be fed into the nip. A speed compensating unit compensates a fluctuation of a rotation speed of the first rotary member occurring when the sheet is fed into the nip. The speed compensating unit adjusts a compensation target value for compensating the fluctuation of the rotation speed of the first rotary member based on the width of the sheet measured by the sheet-width measuring unit.

A belt drive control unit controls a rotation of belt supported by first and second rollers. Each of rotations of the first and second rollers are detected as first and second results. A rotation of the first roller is controlled in connection with thickness fluctuation in the belt using the first and second results. The belt drive control unit includes a sampling data acquisition unit, a correction value generator, a correction value storage, and a correction value reading controller. The sampling data acquisition unit obtains sampling data by sampling a difference value between the first and second results. The correction value generator generates correction value data for the belt based on the sampling data. The correction value storage stores the correction value data. The correction value reading controller reads the correction value data based on a rotation number of the belt to control a rotation of the first roller.

Belt drive control unit, belt drive control method, belt drive control program, and image forming apparatus using same

A control unit calculates a difference between a displacement of a belt detected by an encoder and a predetermined target value, calculates a pulse frequency of a driving pulse signal based on a feedback control based on the difference and a feed-forward control based on a reference driving pulse frequency, sets a control range of the feedback control to be equal to or smaller than a frequency of one rotation of a driven roller, and controls driving of a pulse motor such that the belt moves at a constant speed.

Belt-conveyance control device, image forming apparatus, belt-conveyance control method, and computer program product

In an image forming apparatus, during a rotation of an intermediate transfer belt performed after a contact-state-changing rotation in which the number of photoconductors contacting the intermediate transfer belt has changed, a control unit of a belt driving device controls the driving speed of a belt driving motor based on a period of the intermediate transfer belt determined in the rotation immediately before the contact-state-changing rotation instead of a period determined in the contact-state-changing rotation.

Belt driving device and image forming apparatus

An image forming apparatus includes an image transfer belt, a first pressure member, a second pressure member, and an adjustable tension member. The image transfer belt is trained around multiple rollers for rotation along an endless belt travel path to convey an image for transfer to a recording sheet. The first pressure member is disposed on an outer surface of the image transfer belt. The second pressure member is disposed on an inner surface of the image transfer belt opposite the first pressure member. The first and second pressure members define an image transfer gap therebetween. The adjustable tension member is disposed on the image transfer belt adjacent the image transfer gap to adjust tension on the image transfer belt when the recording sheet enters and exits the image transfer gap.

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Kanagawa, Japan

Toshiyuki Andoh