Abstract: A sheet conveying device includes a first rotating shaft, a driving roller fixed to the first rotating shaft, a driven roller that faces and is pressed against the driving roller, and a second rotating shaft supporting the driven roller. The driving roller or the driven roller includes a cylindrical center portion, and end portions located at both ends of the center portion and having an approximately circular truncated cone shape. Surfaces of the center portion and the end portions are made of an elastic material. An outer surface of the center portion is matched with outer surfaces of one end of the end portions, and a diameter of another end of the end portions is larger than a diameter of the one end. The end portions have a hollow inside, and have a thin surface.

Abstract: An image forming apparatus includes a recording medium transport belt which is suspended by a plurality of roller members. An image is secondarily transferred from a first image carrier through an intermediate transfer body to a recording medium. An image is directly transferred from a second image carrier to the recording medium. The image forming apparatus further includes a pattern image sensing unit which senses a pattern image transferred from the first image carrier and the second image carrier finally to the recording medium transport belt. Each of a distance from a secondary transfer position to a sensing position and a distance from a direct transfer position to the sensing position in a recording medium transport belt rotation direction is a natural number times a circumferential length of a roller member causing a speed change in the recording medium transport belt among the plurality of roller members.

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 includes: a first image carrier; a first image forming unit that forms an image; an intermediate transfer belt; a primary transfer unit that primarily transfers the image onto the intermediate transfer belt; a secondary transfer unit that secondarily transfers the image transferred further onto a recording medium; a second image carrier that transfers the image onto the recording medium; a second image forming unit that forms an image on the second image carrier; a direct transfer unit that directly transfers the image onto the recording medium; a recording medium carriage belt, and a driving roller that drives the recording medium carriage belt; a speed fluctuation detecting unit; and a drive control unit that controls driving of the driving roller so as to reduce the cyclic speed fluctuation of the carriage belt based on a detection result of the speed fluctuation detecting unit.

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 rotation transmission device including a driving member configured to input a driving force; a rotatable member; and a joint configured to transmit the driving force to the rotatable member, wherein the driving member, joint and rotatable member are coaxially arranged, and wherein the driving member are connected with the joint in such a manner that the phase of one-revolution fluctuation of the driving member is different from the phase of one-revolution fluctuation of the joint by an angle of ?.

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: 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: A rotation transmission device including a driving member configured to input a driving force; a rotatable member; and a joint configured to transmit the driving force to the rotatable member, wherein the driving member, joint and rotatable member are coaxially arranged, and wherein the driving member are connected with the joint in such a manner that the phase of one-revolution fluctuation of the driving member is different from the phase of one-revolution fluctuation of the joint by an angle of ?.

Abstract: A drive transmission device that performs drive transmission through a plurality of systems and includes a first involute spline joint to perform drive transmission to a primary rotating body to be driven and a second involute spline joint to perform drive transmission to a secondary rotating body to be driven.

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: 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 at least first, second and third image carriers, a first drive source, a second drive source, at least one visible image forming mechanism for forming a visible image on the image carriers, a transfer unit for overlappingly transferring the visible images, an image detector, and a controller. The first drive source transmits a driving force to at least the first image carrier. The second drive source transmits a driving force to at least two image carriers other than the first image carrier. The controller calculates an amount of misalignment of the overlapped visible images that remain at the start timing of image formation based on the start timing of image formation after the timing correction, and separately determines driving speeds of the first and the second drive sources based on the amount of misalignment of the overlapped visible images.

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.