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: 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: An endless belt is spanned around at least one driving member and at least one supporting member. The driving member is driven by a pulse motor. An angular displacement of the driving member is detected, a difference between detected angular displacement and a target angular displacement is calculated, a frequency of a driving pulse used to drive the pulse motor is calculated based on the difference and a reference driving pulse frequency, and the pulse motor is controlled based on a driving pulse with calculated frequency. The target angular displacement is set so as to cancel a specific velocity fluctuation component of a surface velocity of the belt produced when the drive member is rotated at a constant angular velocity and that is smaller than amount of surface movement of the belt in one driving pulse.

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: A belt drive control device of the present invention is constructed to sense the angular displacement or the angular velocity of a driven roller, separates from the angular displacement or the angular velocity sensed an AC component having a frequency that corresponds to the periodic thickness variation of an endless belt in the circumferential direction, and then controls the rotation of a drive roller in accordance with the amplitude and phase of the AC component.

Abstract: A belt drive control device of the present invention is constructed to sense the angular displacement or the angular velocity of a driven roller, separates from the angular displacement or the angular velocity sensed an AC component having a frequency that corresponds to the periodic thickness variation of an endless belt in the circumferential direction, and then controls the rotation of a drive roller in accordance with the amplitude and phase of the AC component.

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 drive control method includes detecting an angular displacement of a rotor driven by a pulse motor, calculating a difference between the detected angular displacement and a preset target value of the angular displacement, and calculating a drive pulse frequency of a drive pulse signal used to drive the pulse motor. The pulse motor is driven by the drive pulse signal having the drive pulse frequency to allow the rotor at a constant angular velocity.

Abstract: An image forming apparatus including a rotary member having an image formation area, and a scale located at a position outside of the image formation area and on an inner circumference of the rotary member. Also included is a drive device configured to drive the rotary member, a developing device configured to develop an image on the image formation area of the rotary member, and a transfer device configured to transfer the image on the image formation area to a recording sheet. Further included is a sensor configured to detect the scale on the rotary member and to output a signal corresponding to the detection of the scale.

Abstract: A belt drive control device constructed to sense the angular displacement or the angular velocity of a driven roller. The belt drive control device separates, from a sensed angular displacement or the angular velocity, an AC component having a frequency that corresponds to the periodic thickness variation of an endless belt in the circumferential direction, and then controls the rotation of a drive roller in accordance with the amplitude and phase of the AC component.

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 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: An image forming apparatus including a rotary member having an image formation area, and a scale located at a position outside of the image formation area and on an inner circumference of the rotary member. Also included is a drive device configured to drive the rotary member, a developing device configured to develop an image on the image formation area of the rotary member, and a transfer device configured to transfer the image on the image formation area to a recording sheet. Further included is a sensor configured to detect the scale on the rotary member and to output a signal corresponding to the detection of the scale.

Abstract: A drive control method includes detecting an angular displacement of a rotor driven by a pulse motor, calculating a difference between the detected angular displacement and a preset target value of the angular displacement, and calculating a drive pulse frequency of a drive pulse signal used to drive the pulse motor. The pulse motor is driven by the drive pulse signal having the drive pulse frequency to allow the rotor at a constant angular velocity.

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: A belt drive control device of the present invention is constructed to sense the angular displacement or the angular velocity of a driven roller, separates from the angular displacement or the angular velocity sensed an AC component having a frequency that corresponds to the periodic thickness variation of an endless belt in the circumferential direction, and then controls the rotation of a drive roller in accordance with the amplitude and phase of the AC component.

Abstract: An original image reading apparatus comprises an exposure optical system including a scanner optical system which can perform go and return operations, a scanner driving motor which drives said scanner optical system, velocity detecting means for detecting a moving velocity of said scanner optical system and position detecting means for detecting the position of said scanner optical system. In the apparatus, return control is performed which is control of returning said scanner optical system after an original image reading scan has been finished. A target velocity is calculated from a residual distance from a current position of said scanner optical system to a target reference position. Target acceleration is used as feedforward. Velocity control is performed so that detected velocity follows the target velocity.

Abstract: A direct driving mechanism moves, in a direct drive manner, at least one of a sheet, on which an original image to be read is realized, and an image reading system for reading the original image so that the image reading system progressively reads all of the original image accordingly. The image scanning mechanism has an arrangement for reading the original image realized on the sheet either in a first mode of sensing light reflected by the sheet or in a second mode of sensing light transmitted by the sheet. The arrangement includes at least two different kinds of driving mechanisms, each being used for a respective one of the first and second manners. At least one of the two different kinds of driving mechanisms includes the direct driving mechanism.

Abstract: A DC linear motor in which a position and a speed of a movable part relative to a stator can be easily detected by a displacement sensor and a sensor target. The displacement sensor is fixed on the movable part, and the sensor target is fixed on the stator. By properly selecting a shape of the sensor target, a distance y between the sensor target and the displacement sensor corresponds, one to one, to a distance between an initial point of the movable part 1 and a present position thereof. For example, the sensor target may be a plate declined with respect to a direction of motion of the movable part.