Abstract: 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.

Abstract: A sheet conveying device includes a torque estimation unit that, based upon a first load torque generated at a time that a sheet-like member passes through a first nip between a first driving roller and a first driven roller of an upstream sheet conveying unit, estimates a second load torque generated at a time that the sheet-like member passes through a second nip between a second driving roller and a second driven roller of a downstream sheet conveying unit; and a control unit that controls the driving torque such that the second load torque is counterbalanced by applying a counterbalancing torque in synchronization with a timing of entry of the sheet-like member into the second nip.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A sheet conveying device, that can be included in an image forming apparatus, includes a drive source, a drive roller driven by the drive source, a driven roller to press against the drive roller and rotate with the drive roller, an angular velocity detector to detect an angular velocity of the drive roller, a timing estimation unit to estimate a timing when a sheet-type recording medium enters between the drive roller and the driven roller, and a controller to control the drive source based on detection results obtained by the angular velocity detector. The controller includes a feedback control unit to perform feedback control based on data obtained by the angular velocity detector, and a feed-forward control unit to perform feed-forward control based on data obtained by the timing estimation unit.

Abstract: 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.

Abstract: 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.

Abstract: A motor control device includes a pair of rotating members, a driving motor, and a timer-controller. The pair of rotating members nips and conveys a recording medium. The driving motor drives at least one rotating member of the pair of rotating members. The timer-controller calculates a time at which the recording medium passes through a nip formed by the pair of rotating members and controls the driving motor by correcting an excitation time of the driving motor near the time at which the recording medium passes through the nip formed by the pair of rotating members.