Abstract: An image forming system, in which a method of detecting a misregistration of a color image is performed, includes multiple image carriers, an optical writing unit, a transfer member extended by a drive roller and at least one driven roller, a rotation detector, a roller driving unit, a belt controller, an image detector configured to detect the images formed on the surface of the transfer member and obtain detection data, and a controller configured to calculate an amount of misregistration and correct relative misregistration of a scanning line between the image carriers based on a result of the calculation. In the image forming system, a distance from a transfer position to a detection position is an integer multiple of a travel distance of the transfer member during one revolution of the at least one driven roller.

Abstract: An image forming apparatus that includes a plurality of image bearing members, a plurality of drive sources each including a drive gear, a plurality of driven gears, a visible image forming unit, an endless traveling member, a transfer unit, an image detection unit, and a controller. The controller controls rotation of the plurality of image bearing members according to a velocity fluctuation pattern of each surface of the image bearing members based on a detection time interval between predetermined visible detection images formed on the surface of the image bearing member and transferred therefrom to the endless traveling member detected by the image detection unit. Each of the plurality of driven gears includes a gear portion and an engaging portion integrated therewith. The gear portion includes a geared circumference and the engaging portion engages the image bearing member.

Abstract: An image forming apparatus is disclosed. In at least one embodiment, the apparatus includes a plurality of image carriers to carry an image; a plurality of drivers to drive the image carriers; a plurality of drive-force transmitting members to transmit a driving-force from the drivers to image carriers; a developing unit, provided to the image carriers, to develop the image; a transfer member, facing the image carriers, to receive the image from the image carriers sequentially; an image detector to detect the image on the transfer member to check a detection timing of the image; a sensor, provided to each of the image carriers, to detect a rotational speed of image carriers; and a controller to conduct an image-to-image displacement control, a speed-deviation checking, and a phase adjustment control for each of the plurality of image carriers with the image detector and sensor.

Abstract: An image forming apparatus includes a plurality of image bearing members, each of which is configured to bear a portion of a pattern image including a plurality of reference images in a given form, an endless moving member facing the plurality of image bearing members and configured to receive the pattern image, an image detecting unit configured to detect the plurality of reference images, a rotational angle detecting unit configured to separately detect each image bearing member at a given rotational angle, and a controller configured to detect a speed deviation pattern for each revolution of each image bearing member. The controller is configured to detect the speed deviation pattern based on a result obtained from a phase component and a quadrature component of a frequency signal generated from the detection result obtained by the rotational angle detecting unit and a result of detecting the plurality of reference images in the pattern image transferred onto the endless moving member.

Abstract: An image forming apparatus includes a plurality of image bearing members, each of which is configured to bear a portion of a pattern image including a plurality of reference images in a given form, an endless moving member facing the plurality of image bearing members and configured to receive the pattern image, an image detecting unit configured to detect the plurality of reference images, a rotational angle detecting unit configured to separately detect each image bearing member at a given rotational angle, and a controller configured to detect a speed deviation pattern for each revolution of each image bearing member. The controller is configured to detect the speed deviation pattern based on a result obtained from a phase component and a quadrature component of a frequency signal generated from the detection result obtained by the rotational angle detecting unit and a result of detecting the plurality of reference images in the pattern image transferred onto the endless moving member.

Abstract: A driving control device for use in an image forming apparatus includes a control unit that analyzes any one of a speed variation pattern and a thickness variation pattern of an endless belt member of the image forming apparatus per at least one rotation of the endless belt member while endlessly moving the endless belt member by a driving rotating unit, and starts to execute, based on a result of analysis, a driving-speed-control-pattern updating process to update a driving speed control pattern of the driving rotating unit per at least one rotation of the endless belt member, after a power of an image forming apparatus is turned on and within a preparation period in which a predetermined preparation process is completed so that an image forming operation can be started based on an image formation command from an operator.

Abstract: An image forming apparatus includes a primary transfer device that primarily transfers a first image from a first image bearer onto a first belt unit at a primary transfer position, a secondary transfer device that secondarily transfers the first image from the first belt unit onto a printing medium at a secondary transfer position, and a direct transfer device that directly transfers a second image from a second image bearer onto the printing medium at a direct transfer position. A second belt unit is rotatably suspended by plural second rollers and carries and conveys the printing medium through the direct transfer position and the secondary transfer position. An interval between the direct transfer position and the secondary transfer position is prescribed natural number times of a circumference of one of the plural second rollers, which fluctuates a velocity of the second belt unit.

Abstract: An image forming apparatus includes a rotating member, a motor configured to rotate the rotating member, and a marking member having primary and secondary portions. The image forming apparatus also includes a mark sensor configured to detect the primary and secondary portions, and output a primary signal and a secondary signal, and a position sensor configured to determine a rotational position of the rotating member based on a primary reception time of one of the primary and secondary signals that comes immediately after the other of the primary and secondary signals when the position sensor receives the other of the primary and secondary signals at a start of a mark detecting operation. Further, the image forming apparatus includes a motor controller configured to control the motor based on the recognition result and make the rotational position consistent with a target position at a predetermined time during the mark detecting operation.

Abstract: An image forming apparatus uses a method of detecting a phase difference of the image bearing members such that an image transferring member receives a reference toner mark and a reference image pattern carried by and a reference image bearing member and corresponding image patterns carried by respective corresponding image bearing members for at least one circumferential length of each image bearing member perpendicular to the moving direction of the image transferring member, a plurality of detectors detect the reference and corresponding image patterns, and a controller controls the image bearing members to have a positional relation of the reference image bearing member and each corresponding image bearing member for which the sum of the elapsed time difference of the image pattern with respect to the reference image pattern is minimum.

Abstract: An imaging apparatus is disclosed that includes plural image carriers on which different-colored toner images are formed, the image carriers being driven and rotated to transfer the different-colored toner images onto one of an endless transfer member that is driven to rotate in contact with the image carriers or a transfer material that is carried by the endless transfer member. The imaging apparatus includes a phase calculating unit that extracts a periodic rotational variation component of each of the image carriers from a combination of periodic rotational variation components generated within said imaging apparatus and calculates a rotational phase of each of the image carriers based on the extracted periodic rotational variation component, and a rotational phase adjusting unit that adjusts a rotation stop phase of each of the image carriers based on the calculated rotational phase.

Abstract: An image forming apparatus includes a rotating member, a motor configured to rotate the rotating member, and a marking member having primary and secondary portions. The image forming apparatus also includes a mark sensor configured to detect the primary and secondary portions, and output a primary signal and a secondary signal, and a position sensor configured to determine a rotational position of the rotating member based on a primary reception time of one of the primary and secondary signals that comes immediately after the other of the primary and secondary signals when the position sensor receives the other of the primary and secondary signals at a start of a mark detecting operation. Further, the image forming apparatus includes a motor controller configured to control the motor based on the recognition result and make the rotational position consistent with a target position at a predetermined time during the mark detecting operation.

Abstract: A common driving source transmits a drive force to a driving unit that drives a feeding unit and a conveying unit. The driving source is a motor that rotates in either of a normal direction and a reverse direction. The feeding unit includes a mechanical drive-blocking mechanism in its driving sequence. The conveying unit includes a two-system driving sequence and a mechanical drive-blocking mechanism in the driving sequence so as to rotate in one direction regardless of a rotating direction of the driving source. A reduction ratio of each driving sequence in the conveying unit is identical.

Abstract: A color-drift correcting method in an image forming apparatus includes a first and a second color-drift correcting. The first color-drift correcting includes correcting the color-drift amount in a sub scanning direction and a skew relative to the reference color image being based on each color-drift amount of at least three mark-patterns, each of which mark-pattern is formed each color image, so as to decide a corrected-image line as a virtual image line for each color, assumed when the color images are superposed onto a transfer media. A second color-drift correcting includes correcting the color-drift amount in the sub scanning direction so that the virtual image lines corresponding to each of the colors other than the reference color intersect with the virtual image line of the reference color at at least two points.

Abstract: After detecting a speed fluctuation pattern per rotation of a photosensitive drum, a process that forms an image based on image data while causing the photosensitive drum to rotate at a nonstandard linear speed is executed as an image forming process by driving a process driving motor that drives the photosensitive drum to curb a speed fluctuation of the photosensitive drum by using a driving speed fine tuning pattern. Before executing the image forming process, a fine-tuning-pattern correcting process is executed for correcting the driving speed fine tuning pattern of the process driving motor, based on the nonstandard linear speed.

Abstract: An image forming apparatus includes a plurality of image carriers, an optical writing unit, a plurality of developing units, a transfer member, a transfer unit, an image sensor, and a control unit. In at least one embodiment, the image sensor is configured to sense a positional displacement detection pattern including visible images on the transfer member to detect a positional displacement between the visible images on each of the plurality of image carriers. The control unit is configured to execute a positional displacement correction control to calculate an amount of the positional displacement and determine respective target drive speeds of the plurality of drive sources. The control unit is also configured to control so that the positional displacement detection pattern is formed when the plurality of drive sources are driven at substantially identical speeds and the positional displacement detection pattern thus formed is sensed by the image sensor.

Abstract: An image forming apparatus includes: image detectors to detect conditions of images, respectively, formed on a transfer member; sensors to detect rotational displacements of latent image carriers, respectively; and a controller to perform at least phase adjustment control and image-to-image displacement control before performing image forming operations on image carriers, respectively. Image-to-image displacement control includes adjusting image forming timing on the image carriers based upon conditions of a detection image (including images transferred from the image carrier) detected by the image detectors, respectively. Speed-variation detection control includes detecting a condition of a speed-variation detection image (including an image transferred from each of image carriers) via the image detectors, and determining speed variation of the image carriers, respectively, per one revolution based upon outputs of the image detectors and the sensors.

Abstract: An image forming apparatus, in which a program for carrying out an image forming method is provided, includes a transfer member to receive respective images formed on a plurality of image bearing members, an image detecting unit to detect the images conveyed on the transfer member, a paper length detecting unit to detect a length of a recording medium in a sheet travel direction, a counting unit to count the number of recording media and to change a count up value according to a detection result by the paper length detecting unit, and a control unit to control an image forming timing with respect to the image bearing members based on a detection timing of the image and to perform a positional deviation adjustment each time a counted value increases by a predetermined amount so as to reduce an amount of a positional deviation of the image.

Abstract: 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.

Abstract: An image forming apparatus to form an image on a recording medium, capable of reducing deterioration of image bearer, is disclosed. In one embodiment, the image forming apparatus includes an image bearer, a driver to move the image bearer, a image forming device to form a visible image on the image bearer, a contacting member to form a nip by contacting with the image bearer, and a controller to control the driver for driving stop with a distance shifted on a surface of the image bearer from a start of driving. An amount of the shifted distance is greater than a width of the nip and is not a divisional number of a peripheral length of the image bearer.

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.