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 first pattern having lines of a first color and a second pattern having lines of a second color are formed on an image transferring member near the side edges thereof. Each of the first and second color lines are sequentially detected by a sensor. Absolute values of time differences between detection of first lines and corresponding second lines are calculated. This process of detection of the time differences is repeated several times while changing the rotational phase of the an image carrying member for the second color. A position where the time difference is relatively lowest or even the minimum is selected.

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 method in which an electrostatic latent image is formed by exposure with an exposure light of light scanning means onto an image carrier charged by charging means, visualization of the electrostatic latent image as a toner image, transfer of the toner image onto a transfer member by application of a bias voltage, and removal of the toner remaining on the image carrier following transfer with a cleaning blade, the exposure being initiated by the light scanning means after a position“a” on the image carrier where said bias voltage has been initiated passes the cleaning blade.

Abstract: A color printing apparatus having a color registration difference correction function, the color registration difference caused by a difference of rotation speeds of each photosensitive drum after a print mode changes from a one photosensitive drum mode to an all photosensitive drums mode.

Abstract: An image forming apparatus including at least one image bearing member configured to bear a toner image on a surface thereof, and a transferring member arranged close to or in contact with the at least one image bearing member and configured to rotate in substantially synchronism with the at least one image bearing member to transfer the toner image born on the at least one image bearing member onto a recording medium. The apparatus further includes at least one first motor rotating the at least one image bearing member, a second motor rotating the transferring member, and a control mechanism configured to control a rotation number of at least one of the at least one first motor and the second motor during at least one of rise and fall time periods with a command clock signal and a feedback signal in accordance with a predetermined velocity curve.

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: 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 includes a plurality of image bearing members configured to bear respective images, an optical writing unit configured to write the respective images on the plurality of image bearing members by deflecting a laser beam on a polygon mirror, a transfer unit configured to transfer the respective images onto an image receiving member, and a controlling unit configured to perform an adjustment of a difference in phase of respective rotation speeds between the plurality of image bearing members at a timing of one of non-image forming operations during a series of image forming operations performed by the plurality of image bearing members, the optical writing unit, and the transfer unit.

Abstract: An image forming apparatus includes a plurality of process cartridges. Each process cartridge includes an image carrier configured to form an image intermediately, a drive transfer member engaged with the image carrier, a drive mechanism configured to drive to rotate the image carrier via the drive transfer member, a marking member mounted on the drive transfer member and configured to indicate a rotational position of the drive transfer member, a detector configured to detect the rotational position by detecting the marking member, and a balancer mounted on the drive transfer member configured to match a weighted center of the drive transfer member with a shaft center of the image carrier. A controller is configured to adjust rotational phases of the image carriers based on results detected by the detector.

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: A first pattern having lines of a first color and a second pattern having lines of a second color are formed on an image transferring member near the side edges thereof. Each of the first and second color lines are sequentially detected by a sensor. Absolute values of time differences between detection of first lines and corresponding second lines are calculated. This process of detection of the time differences is repeated several times while changing the rotational phase of the an image carrying member for the second color. A position where the time difference is relatively lowest or even the minimum is selected.

Abstract: An image forming apparatus including at least one image bearing member configured to bear a toner image on a surface thereof, and a transferring member arranged close to or in contact with the at least one image bearing member and configured to rotate in substantially synchronism with the at least one image bearing member to transfer the toner image born on the at least one image bearing member onto a recording medium. The apparatus further includes at least one first motor rotating the at least one image bearing member, a second motor rotating the transferring member, and a control mechanism configured to control a rotation number of at least one of the at least one first motor and the second motor during at least one of rise and fall time periods with a command clock signal and a feedback signal in accordance with a predetermined velocity curve.

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.