An image-forming device has a plurality of cylindrical image-carrying members, and an optical scanning unit. The plurality of cylindrical image-carrying members is provided in a main casing for rotating about respective rotational axes. The rotational axes are parallel to one another and juxtaposed in a single direction. The optical scanning unit is provided in the main casing and has a plurality of laser generators, a single rotatable polygon mirror, a plurality of mirrors, and a plurality of lenses. The plurality of laser generators is provided one-to-one relationship to the plurality of image-carrying members to emit respective laser beams. The single rotatable polygon mirror deflects the respective laser beams to scan the respective image-carrying members therewith. The plurality of mirrors is provided one-to-one relationship to the plurality of image-carrying members to guide the respective laser beams along respective optical paths to the respective image-carrying members. The plurality of lenses is provided one-to-one relationship to the plurality of image-carrying members and provided in the respective optical paths and between the respective mirrors and the respective image-carrying members. Distances from the respective mirrors to the respective image-carrying members being equal to one another.

Image-forming device

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.

Belt-drive control device, color-shift detecting method, color-shift detecting device, and image forming apparatus

A rotational speed of a first roller and a time required for a second roller to make one rotation are measured. A controller calculates an amplitude and a phase of fluctuation in a rotational speed in one rotation period of the first roller while the first roller is rotated by a predefined angle based on the speed and the time. The controller corrects measured speed of the first roller based on the amplitude and the phase, and controls a driving roller based on corrected speed.

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

An image forming apparatus including an image carrying member, a transfer member, support rollers, a detecting mechanism, and a controller. The image carrying member forms a toner image on its surface facing a surface of the transfer member, supported by the support rollers, which transfers the toner image to a recording medium. The detecting mechanism includes a detection roller, a roller shaft, a moving member, and a sensor, and detects a speed of the transfer member. The detection roller includes one support roller selected from the support rollers, and is provided with the roller shaft. The moving member is directly fixed to the roller shaft and rotates with the detection roller. The sensor detects a moving speed of the detection roller with the moving member. The controller controls a traveling speed of the transfer member to a target speed based on a detection result of the sensor.

Method and apparatus for image forming capable of effectively reducing unevenness of density and color displacement of images

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.

Apparatus for controlling driving of endless belt, and image forming apparatus

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.

Apparatus for and method of driving motor to move object at a constant velocity

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.

Method, apparatus, and program for driving a motor in a feedback control system, capable of suppressing motor oscillation

An image formation apparatus is disclosed, wherein temperatures of two or more places on a transfer/conveyance belt are measured. Timing of writing to photo conductor drums based on pixel clock signals is controlled in reference to differences between the measured temperatures, while a printing medium is being conveyed.

Yohhei Miura

Papers

Apparatus for and method of driving motor to move object at a constant velocity

Method and apparatus for image forming capable of effectively reducing unevenness of density and color displacement of images

Method, apparatus, and program for driving a motor in a feedback control system, capable of suppressing motor oscillation

Image formation apparatus having exposure timing control

Apparatus for image forming