Abstract: A pressing drive mechanism, which drives a secondary transfer roller to press an intermediate transfer belt, includes: a motor that generates a driving force for driving the secondary transfer roller in a driving direction; a transmission mechanism that transmits the driving force to the secondary transfer roller to drive the secondary transfer roller in the driving direction; a hardware processor that controls the driving force of the motor to control a position in the driving direction of the secondary transfer roller; and a biasing member that biases the secondary transfer roller in a direction of pressing the intermediate transfer belt. The hardware processor controls the driving force of the motor in synchronization with a timing at which a front end of a sheet reaches the secondary transfer roller; and drives the secondary transfer roller to a predetermined pressing position by using a biasing force by the biasing member.

Abstract: An image forming apparatus includes: a hardware processor that performs feedforward control on a motor; a driving roller that drives an intermediate transfer belt for transferring a toner image; a drive transmission system that transmits a driving force of the motor; a first detector that detects a speed of a driving shaft of the motor; a second detector that detects a speed of a driving shaft of the drive transmission system; and a storage that stores a plurality of sets of control data having different conformity states, wherein the plurality of sets of control data include pairs of a feedforward operation pattern and a drive transmission system deformation pattern, the drive transmission system deformation pattern corresponds to a fluctuation pattern of difference values, and the hardware processor compares the fluctuation pattern of difference values with the plurality of sets of control data.

Abstract: An image forming apparatus including: a photoreceptor drum; an intermediate transfer belt; a primary transferer; a secondary transferer, and a hardware processor which suppresses speed change of the intermediate transfer belt at a timing of the sheet entering the secondary transferer and at a timing of the sheet being ejected from the secondary transferer, wherein the hardware processor calculates speed changes of the intermediate transfer belt and the photoreceptor drum at the timing of the sheet entering the secondary transferer and at the timing of the sheet being ejected from the secondary transferer, and calculates a transmission rate between the intermediate transfer belt and the photoreceptor drum based on the calculated speed changes, and the hardware processor adjusts an operation amount of the driving roller based on the calculated transmission rate.

Abstract: An image forming apparatus includes: a driving roller that conveys a paper sheet; a detector that detects a desired point on the driving roller; and a hardware processor that: acquires a waveform signal indicating one of a change in an image forming position with respect to the paper sheet and a change in a sheet conveyance velocity; extracts a synchronous waveform signal from the waveform signal acquired by the hardware processor, the synchronous waveform signal being synchronized with one revolution of the driving roller, the one revolution being detected by the detector; and inputs a drive signal to a drive source of the driving roller, the drive signal being input to weaken an amplitude of the synchronous waveform signal extracted by the hardware processor.

Abstract: An image forming apparatus includes: a hardware processor that performs feedforward control on a motor; a driving roller that drives an intermediate transfer belt for transferring a toner image; a drive transmission system that transmits a driving force of the motor; a first detector that detects a speed of a driving shaft of the motor; a second detector that detects a speed of a driving shaft of the drive transmission system; and a storage that stores a plurality of sets of control data having different conformity states, wherein the plurality of sets of control data include pairs of a feedforward operation pattern and a drive transmission system deformation pattern, the drive transmission system deformation pattern corresponds to a fluctuation pattern of difference values, and the hardware processor compares the fluctuation pattern of difference values with the plurality of sets of control data.

Abstract: An image forming apparatus includes: a photosensitive drum; a driving roller that drives a transfer member; a facing roller facing the driving roller; a driver that drives one of the photosensitive drum, the driving roller, and the facing roller; and a hardware processor that: acquires carry-in fluctuation information of speed fluctuation of any one of the photosensitive drum, the driving roller, and the facing roller when a sheet member is carried into the transfer member; detects carry-in fluctuation timing of the speed fluctuation of any one of the photosensitive drum, the driving roller, and the facing roller that occurs when the sheet member is carried into the transfer member; predicts carry-out fluctuation timing of speed fluctuation of any one of the photosensitive drum, the driving roller, and the facing roller that occurs when the sheet member is carried from the transfer member; and performs feedforward control on the driver.

Abstract: An image forming apparatus including: a photoreceptor drum; an intermediate transfer belt; a primary transferer; a secondary transferer, and a hardware processor which suppresses speed change of the intermediate transfer belt at a timing of the sheet entering the secondary transferer and at a timing of the sheet being ejected from the secondary transferer, wherein the hardware processor calculates speed changes of the intermediate transfer belt and the photoreceptor drum at the timing of the sheet entering the secondary transferer and at the timing of the sheet being ejected from the secondary transferer, and calculates a transmission rate between the intermediate transfer belt and the photoreceptor drum based on the calculated speed changes, and the hardware processor adjusts an operation amount of the driving roller based on the calculated transmission rate.

Abstract: A driving device includes: a first driving source; a second driving source; a first gear to which a driving force is transmitted from the first driving source; a second gear to which a driving force is transmitted from the second driving source; a third gear that engages with the first gear and the second gear; and a fixation shaft that pivotally supports the third gear, the fixation shaft being disposed such that a center of the fixation shaft, a rotation center of the first gear and a rotation center of the second gear are disposed on a straight line in which the fixation shaft is provided through the third gear; and a hole having a diameter for compensating eccentricity of the first gear, the second gear and the third gear is formed in the third gear.

Abstract: An image forming apparatus includes: a driving roller that conveys a paper sheet; a detector that detects a desired point on the driving roller; and a hardware processor that: acquires a waveform signal indicating one of a change in an image forming position with respect to the paper sheet and a change in a sheet conveyance velocity; extracts a synchronous waveform signal from the waveform signal acquired by the hardware processor, the synchronous waveform signal being synchronized with one revolution of the driving roller, the one revolution being detected by the detector; and inputs a drive signal to a drive source of the driving roller, the drive signal being input to weaken an amplitude of the synchronous waveform signal extracted by the hardware processor.

Abstract: An image forming apparatus includes: a photosensitive drum; a driving roller that drives a transfer member; a facing roller facing the driving roller; a driver that drives one of the photosensitive drum, the driving roller, and the facing roller; and a hardware processor that: acquires carry-in fluctuation information of speed fluctuation of any one of the photosensitive drum, the driving roller, and the facing roller when a sheet member is carried into the transfer member; detects carry-in fluctuation timing of the speed fluctuation of any one of the photosensitive drum, the driving roller, and the facing roller that occurs when the sheet member is carried into the transfer member; predicts carry-out fluctuation timing of speed fluctuation of any one of the photosensitive drum, the driving roller, and the facing roller that occurs when the sheet member is carried from the transfer member; and performs feedforward control on the driver.

Abstract: An image forming apparatus includes: a first roller having an elastic part; a second roller configured to form a nip between the first roller and the second roller; a holding member configured to hold the second roller; and a control section configured to control the position of the holding member such that the center distance between the first roller and the second roller is maintained at a constant value when a sheet passes through the nip.

Abstract: A belt tension adjustment mechanism provided on an inner side of an endless intermediate transfer belt and applying a tension to the intermediate transfer belt being rotated when a toner image is transferred on the intermediate transfer belt, said belt tension adjustment mechanism includes a holder having an opening section at one surface thereof; and an elastic member contained to be fixed in the holder while being compressed in a running direction of the intermediate transfer belt and having a convex section, wherein the convex section protrudes from the opening section of the holder toward a direction orthogonal to an image transfer surface of the intermediate transfer belt and is in direct contact with the intermediate transfer belt.

Abstract: A sheet feeder device includes: a sheet feed tray configured to store a sheet stack formed with a plurality of paper sheets; an elastic member capable of expanding and contracting; a contact mechanism configured to bring the elastic member into contact with an edge of the sheet stack; an expansion mechanism configured to expand the elastic member in a direction of stacking of the paper sheets; and a control unit configured to cause the expansion mechanism to expand the elastic member while the elastic member is kept in contact with the edge of the sheet stack by the contact mechanism.

Abstract: A driving device includes: a first driving source; a second driving source; a first gear to which a driving force is transmitted from the first driving source; a second gear to which a driving force is transmitted from the second driving source; a third gear that engages with the first gear and the second gear; and a fixation shaft that pivotally supports the third gear, the fixation shaft being disposed such that a center of the fixation shaft, a rotation center of the first gear and a rotation center of the second gear are disposed on a straight line in which the fixation shaft is provided through the third gear; and a hole having a diameter for compensating eccentricity of the first gear, the second gear and the third gear is formed in the third gear.

Abstract: A sheet feeder device includes: a sheet feed tray configured to store a sheet stack formed with a plurality of paper sheets; an elastic member capable of expanding and contracting; a contact mechanism configured to bring the elastic member into contact with an edge of the sheet stack; an expansion mechanism configured to expand the elastic member in a direction of stacking of the paper sheets; and a control unit configured to cause the expansion mechanism to expand the elastic member while the elastic member is kept in contact with the edge of the sheet stack by the contact mechanism.

Abstract: An image forming apparatus includes upstream-side and downstream-side detection parts and a control section. The detection parts are disposed on a moving path of an intermediate transfer belt or a conveyor belt and detect a speed of the belt. The control section performs control to correct color misregistration of images composed of colors to be formed on the intermediate transfer belt or a recording medium conveyed by the conveyance belt on the basis of the detection result. The control unit calculates a difference between the speed detected by the upstream-side detection part and the speed detected by the downstream-side detection part after a predetermined time elapses since the upstream-side detection part detects the speed and performs the control on the basis of the difference. The predetermined time is obtained by dividing a distance between the detection parts by a target speed of the belt.

Abstract: A belt tension adjustment mechanism provided on an inner side of an endless intermediate transfer belt and applying a tension to the intermediate transfer belt being rotated when a toner image is transferred on the intermediate transfer belt, said belt tension adjustment mechanism includes a holder having an opening section at one surface thereof; and an elastic member contained to be fixed in the holder while being compressed in a running direction of the intermediate transfer belt and having a convex section, wherein the convex section protrudes from the opening section of the holder toward a direction orthogonal to an image transfer surface of the intermediate transfer belt and is in direct contact with the intermediate transfer belt.

Abstract: An image forming apparatus includes: a first roller having an elastic part; a second roller configured to form a nip between the first roller and the second roller; a holding member configured to hold the second roller; and a control section configured to control the position of the holding member such that the center distance between the first roller and the second roller is maintained at a constant value when a sheet passes through the nip.

Abstract: A belt tension adjustment mechanism which is provided on an inner side of an endless intermediate transfer belt and applies a tension to the intermediate transfer belt, the intermediate transfer belt being rotated when a toner image is transferred, and the belt tension adjustment mechanism including an elastic member which reduces a load applied to the intermediate transfer belt along with an increase in an inward displacement amount of the intermediate transfer belt.

Abstract: An image forming apparatus comprises a drive motor configured to rotate the lower pressure roller, a torque generation unit for generating a braking force in the direction to hinder rotation of a fixing belt in order to adjust the differential speed between the surface speed of the fixing belt and the surface speed of the lower pressure roller, and a control unit for adjusting the braking force generated by the torque generation unit. The control unit adjusts the braking force generated by the torque generation unit to decrease if the rotational torque of the drive motor is larger than a predetermined target torque, and increase if the rotational torque of the drive motor is smaller than the predetermined target torque.