Abstract: An optical encoder includes a light emitting unit that emits parallel light onto a plurality of marks that are arranged on an object such as a rotor or a belt, at a predetermined interval in a moving direction of the object, and a light receiving unit that receives light modulated by the marks. The parallel light is generated by a collimating lens.

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: An image forming apparatus includes a belt stretched across rollers and a resist rotary member that feeds out a recording medium on the belt. A correlation between a velocity of the belt and the resist rotary member is obtained. A target velocity of the belt or the resist rotary member, at which a difference between the velocity when the recording medium is in contact with both the belt and the resist rotary member and the velocity when the recording medium is not in contact with at least either the belt or the resist rotary member is minimum, is determined based on the correlation.

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.

Abstract: A belt driving control apparatus, the belt driving control apparatus having an endless belt, a driving roller driving the endless belt, a driving motor driving the driving roller, at least one idler roller being dependent on the endless belt, and an encoder attached to one idler roller. The belt driving control apparatus includes a structure where a control target value of the driving motor is set so that an effective speed of the endless belt is constant and the driving motor is drive-controlled so that the control target value is satisfied.

Abstract: A mark detecting unit detects a mark that is a reference position of an endless belt. An angular-displacement-error detecting unit detects an angular displacement error of an encoder caused by thickness fluctuation of the endless belt. A first calculating unit calculates a phase and a maximum amplitude to the mark. A second calculating unit calculates correction data according to a distance from the mark on the endless belt. A belt-drive control device controls a belt driving unit by adding the correction data to a preset control target value to stabilize speed fluctuation of the endless belt due to the thickness fluctuation.

Abstract: A color image forming apparatus including a plurality of photosensitive drums on which toner images of different colors are respectively formed. An endless belt confronts the plurality of photosensitive drums. A drive source drives rotation of the endless belt, or alternatively plural drive sources drive the photosensitive drums to individually rotate. A memory stores pre-measured characteristics of a color misregistration of a color image in a sub-scanning direction of the apparatus, the color image formed by transferring images from respective of the plurality of photosensitive drums. Further, a control unit changes an average running speed of the endless belt, or alternatively an average running speed of at least some of the photosensitive drums, by controlling the drive sources, to compensate for color misregistration, based on the stored characteristics of color misregistration. The belt can either transport a paper sheet or have a color image formed thereon as an intermediate transfer device.

Abstract: A method, apparatus, and program for driving a motor in a feedback control system, capable of suppressing oscillation of the motor rotational speed are disclosed. A motor drive controller includes a drive motor, a detector, and a motor drive controller. The drive motor drives a moving body around a target speed. The detector detects a current moving speed of the moving body and outputs it as a detector pulse signal. The controller calculates a difference between the current moving speed and the target moving speed, calculates a control value based on the difference, calculates a pulse rate of a drive pulse signal based on the control value after having controlled the control value to be within a predetermined value, and controls the drive motor based on the pulse rate.

Abstract: A composite tube formed by covering an outer surface of a tube with a foam, characterized in that: the foam is formed of layers composed of bar-shaped foams; and in a section perpendicular to a longitudinal direction of the foam, each of 40% or more of the bar-shaped foams is formed as a substantially fan-shaped figure formed by long and short arc portions of two large and small concentric circles, respectively, and two linear portions extending radially toward an outer periphery from the center of the concentric circles, with the figure satisfying the condition of formula (1): 0.5<a/b<2.5 ??Formula (1) where a is a length corresponding to ½ of the sum of the lengths of the long arc portion and the short arc portion of a substantially fan-shaped figure, and b is the length of each of the linear portions of the substantially fan-shaped figure.

Abstract: An image forming apparatus includes an image carrier that carries an image and rotates, a transfer member that rotates in contact with the image carrier and transfers an image formed on the image carrier to a recording medium, a conveying unit that conveys the recording medium to a contact position where the image carrier and the transfer member come into contact with each other, and a gap forming unit that forms a gap between the image carrier and the transfer member at the contact position. The gap forming unit forms the gap immediately before the recording medium enters the contact position.

Abstract: A method, apparatus, and program for driving a motor in a feedback control system, capable of suppressing oscillation of the motor are disclosed. A motor drive controller includes a drive motor, a detector, and a motor drive controller. The drive motor drives a moving body around a target moving speed. The detector detects a current moving speed of the moving body and output it as a detector pulse signal. The controller calculates a difference between the current moving speed and the target moving speed, calculates a control value based on the difference, calculates a pulse rate of a drive pulse signal based on the control value after having controlled the control value to be within a predetermined value, and feedback controls the drive motor based on the pulse rate.

Abstract: To compensate for the variation in the output signal from an encoder due to the variation in the thickness of an endless belt, an apparatus includes: a detector that detects a reference position on the endless belt; a correction-value calculating unit that calculates a correction value for each position on the endless belt based on the thickness; and a target-value calculating unit that adjusts a target value for controlling a driving motor based on the correction value corresponding to a distance from the reference position to the current position.

Abstract: An image forming apparatus includes a latent image carrier having a moving surface on which a latent image is formed, a drive control mechanism to control a drive of the latent image carrier so as to match a rotation angular speed of the latent image carrier with a target rotation angular speed thereof, a surface moving member having a moving surface on which an adjustment pattern for use in controlling the drive of the latent image carrier is formed, an image forming mechanism to develop the latent image with toner and transfer a resultant toner image on the surface moving member so as to form the adjustment pattern along a surface moving direction thereof, a pattern sensor to detect the adjustment pattern, a correction mechanism to correct the target rotation angular speed of the latent image carrier based on an amplitude and a phase of a variable component in a pattern interval of the adjustment pattern detected with the pattern sensor.

Abstract: Driving of a pulse motor is controlled in such a manner that a rotating body driven by the pulse motor rotates at a uniform angular velocity. Angular displacement of the rotating body is detected, a difference between a detection value of the angular displacement and a target value of angular displacement set in advance is calculated, and a drive pulse frequency of a drive pulse signal to be used for driving the pulse motor is calculated based on the difference and a reference drive pulse frequency. Whether the difference is added to the reference drive pulse can be selected.

Abstract: A belt driving controller includes a driving roller having a radius r1, a plurality of driven rollers that is driven by rotation of the driving roller, the driven rollers having a radius r2, an endless belt that is wound on the driving roller and the driven rollers and an encoder that is attached to one of the driven rollers, and that outputs a signal. The rotation of the driving roller is controlled based on the signal from the encoder, and (?2/?1)×(r1/r2)?1 is satisfied where ?1 is a correction coefficient for a fluctuation in thickness of the endless belt caused by a belt winding angle on the driving roller, and ?2 is a correction coefficient for a fluctuation in the thickness on the driven roller.

Abstract: A belt driving control apparatus, the belt driving control apparatus having an endless belt, a driving roller driving the endless belt, a driving motor driving the driving roller, at least one idler roller being dependent on the endless belt, and an encoder attached to one of the idler roller, the belt driving control apparatus includes a structure where a control target value of the driving motor is set so that an effective speed of the endless belt is constant and the driving motor is drive-controlled so that the control target value is satisfied.