A cam driver includes a support, a cam, a motor, and a retracting torque applicator. The support supports an object. The cam moves the support. The motor rotates the cam and maintains a position of the cam. The retracting torque applicator applies torque to the cam in a direction to move the object away from a counter object that faces the object.

An optical sensor irradiates a control toner image formed on an intermediate transfer belt with light and detect refection light of the light. A controller executes an abnormality diagnosis mode in a case where change in the phase of a cam is not detected by a phase detection portion until an elapse of a predetermined time or more since a start of output of a driving signal for driving a separation mechanism. In execution of the abnormality diagnosis mode, the controller outputs the driving signal for driving the separation mechanism, and is capable of outputting information about an abnormality of the phase detection portion and information about an abnormality of the separation mechanism and/or a driving unit on a basis of a detection result of the optical sensor that is obtained in a case where the light is radiated from the optical sensor while the driving signal is output.

One aspect is an image forming apparatus including a motor that drives a first member, a second member, a movement member that moves between a first position where the first and second members contact and a second position where the first and second members are separated, and a controller that receives an instruction to start a print job for forming an image on a recording medium, and executes an initial operation for determining a phase of a rotor of the motor in a stopping state of the rotor based on current flowing through a coil of the motor by supplying current to the coil in the stopping state in a state where the movement member is located at the first position, to control the current supplied to the coil to rotate the rotor in the stopping state based on the phase determined in the initial operation.

An image forming apparatus, having process units, a transfer unit, a motor, first through fourth cams, a color-linkage gear train, a monochrome-transmission gear train, and a color-transmission gear train, is provided. Each of the process units has a developing unit including a developing roller and a drum unit including a photosensitive drum. The color-linkage gear train rotates the first cam, the second cam, and the third cam in shifted phases. The monochrome-transmission gear train transmits a driving force from the motor to a monochrome clutch, which engages and disengages transmission of the driving force from the monochrome-transmission gear train to the fourth cam. The color-transmission gear train transmits the driving force from the motor to a color clutch, which engages and disengages transmission of the driving force from the color-transmission gear train to the color-linkage gear train.

In one example, a device comprises an image transfer member, a platen to form a first nip with the image transfer member, a photo imaging plate to form a second nip with the image transfer member, and a controller to determine first information relating to a characteristic of the first nip, and to determine second information for use in adjusting a relative position of the photo imaging plate and the image transfer member on the basis of the first information.

An image forming apparatus includes a latent image bearer, a toner image forming unit, an intermediate transfer member, a primary transfer member, a secondary transfer member, a switching unit, and control circuitry. The toner image forming unit forms toner images on the latent image bearer. The primary transfer member transfers the toner images on the latent image bearer onto the intermediate transfer member. The secondary transfer member transfers the toner images on the intermediate transfer member onto recording materials. The switching unit switches a position of one of the secondary transfer member and the intermediate transfer member between a first and a second position. The control circuitry controls at least one of a first and a second operation. The control circuitry changes at least one of the first and the second operation when the toner images satisfy a specified abnormal image reduction condition at a first and a second timing.

An image forming apparatus includes a first image forming unit, a second image forming unit, and a control unit configured to control the first image forming unit and the second image forming unit. The control unit performs control so as to allow execution of a first mode and a second mode in which a color gamut of an image to be formed on a printing material is expanded from the first mode, as an image forming mode for forming an image on a printing material. The second mode includes a second single-color mode in which image formation is performed by only the first image forming unit and a second multicolor mode in which image formation is performed by the first image forming unit and the second image forming unit.

In one example, a device comprises an image transfer member, a platen to form a first nip with the image transfer member, a photo imaging plate to form a second nip with the image transfer member, and a controller to determine first information relating to a characteristic of the first nip, and to determine second information for use in adjusting a relative position of the photo imaging plate and the image transfer member on the basis of the first information.

An image forming apparatus includes a latent image bearer, a toner image forming unit, an intermediate transfer member, a primary transfer member, a secondary transfer member, a switching unit, and control circuitry. The toner image forming unit forms toner images on the latent image bearer. The primary transfer member transfers the toner images on the latent image bearer onto the intermediate transfer member. The secondary transfer member transfers the toner images on the intermediate transfer member onto recording materials. The switching unit switches a position of one of the secondary transfer member and the intermediate transfer member between a first and a second position. The control circuitry controls at least one of a first and a second operation. The control circuitry changes at least one of the first and the second operation when the toner images satisfy a specified abnormal image reduction condition at a first and a second timing.

An image forming apparatus includes an image forming part, a canceling processing part, a first switching processing part and a second switching processing part. The canceling processing part is performable an image canceling operation where a toner image formed on an intermediate transferring member is removed from the intermediate transferring member without transferred to a sheet. The first switching processing part is capable of switching a printing mode in the image forming part between a plurality of printing modes having different printing conditions in the image forming part, based on an image data under waiting for printing and a predetermined first switching condition. The second switching processing part is capable of switching the printing mode based on the image data under waiting for printing and a predetermined second switching condition when the image canceling operation is performed.