A rotating member control device that controls a first rotating member and a second rotating member to convey a sheet includes a processor configured to execute a program to implement processes of controlling the first rotating member and the second rotating member to come into contact or be separated from each other and acquiring a value that corresponds to or is proportional to a driving torque of a first driving unit that rotationally drives the first rotating member. The processor acquires the value upon separation when the first rotating member and the second rotating member are separated from each other and upon conveyance when the sheet is held between and conveyed by the first rotating member and the second rotating member. The processor further sets a rotational speed of the second rotating member such that the value acquired upon separation and the value acquired upon conveyance become equal.

An image forming apparatus includes a drive device including a first drive transmission passage through which a driving force of a drive source is transmitted to a developer bearer via a first joint and a second drive transmission passage through which the driving force is transmitted to a rotary body via a second joint. The first drive transmission passage and the second drive transmission passage are defined such that one of a first drive transmission ratio to the first joint of the first drive transmission passage and a second drive transmission ratio to the second joint of the second drive transmission passage is an integral multiple of the other of the first drive transmission ratio from the drive source to the first joint of the first drive transmission passage and the second drive transmission ratio from the drive source to the second joint of the second drive transmission passage.

Disclosed is an image forming apparatus which includes: a feeding portion configured to feed a sheet; an image forming portion configured to form an image on the sheet; a conveying portion configured to stop the sheet fed by the feeding portion at a predetermined position and to convey the sheet to the image forming portion in accordance with a timing of forming the image by the image forming portion; a type discriminating portion configured to discriminate whether a type of the sheet to be fed belongs to a first sheet type group including plain paper or to a second sheet type group including coated paper; and a controlling portion configured to control feeding of the sheet, wherein the controlling portion is configured to change a sheet feeding start timing of the feeding portion in accordance with the type discriminated by the type discriminating portion.

In a drive mechanism, a first engagement portion of a drive member includes a first contact portion capable of contacting with a second engagement portion in a case where a coupling member is at a first position and the drive member rotates in a first rotation direction, a second contact portion capable of contacting with the second engagement portion in a case where the coupling member is at a second position and the drive member rotates in the first rotation direction, and a third contact portion capable of contacting with the coupling member so as to regulate movement of the second engagement portion from the second position to the first position in a rotation axis direction when the coupling member is at the second position and the second contact portion and the coupling member are in a contact state by rotation of the drive member in the first rotation direction.

An image forming apparatus includes a photosensitive drum, a developing member, an applying device forming a developing potential on the developing member, a driver rotationally driving the developing member, and a controller. The controller selectively executes an operation in first and second modes by controlling a circumferential speed ratio of a circumferential speed of the developing member to a circumferential speed of the drum and a potential difference between a surface potential of the image bearing member in a region where an electrostatic latent image is formed and the developing potential. In the first mode, the ratio is a first ratio of 50% to 100% and the potential difference is a first potential difference, and in the second mode the ratio is a second ratio larger than the first ratio and less than 150% and the potential difference is a second potential difference less than the first potential difference.

An image forming apparatus includes an image bearing member, an intermediary transfer member having ion conductivity and a rotatable endless belt shape, a primary transfer member, a secondary transfer member, a cleaning member, an environment sensor and a controller. Based on a result of the environment sensor, the controller controls so as to change a current balance based on an integrated value of a first current value and an integrated value of a second current value. The first current value is a current flowing from inside of the intermediary transfer member to outside thereof and the second current value is a current flowing from outside of the intermediary transfer member to inside thereof.

An image forming apparatus includes image bearers, motors, a reference position detector, and processing circuitry. The circuitry senses a density of a toner image on each bearer; forms an image pattern and senses, based on a detection result of the detector and a sensing result of the density, density unevenness in a rotation cycle and a phase of the density unevenness with respect to a rotational position reference of each bearer; calculates a target phase based on the phase sensed; calculates a relative phase difference based on a rotational position and the target phase of each bearer; selects, as a reference image bearer, an image bearer having a minimum phase correction value, based on a calculation result of the difference; and controls the rotational position of each of the other image bearers with respect to the reference image bearer to the phase correction value, with the motors being driven.

An apparatus according to the aspect of the embodiments includes a phase determiner configured to determine a rotational phase of a rotor, a speed determiner configured to determine a rotational speed of the rotor, a controller having a first control mode for controlling the motor by supplying constant currents to windings, and a discriminator configured to discriminate whether a rotation of the motor is abnormal based on the rotational speed when the rotational speed corresponding to a command speed is equal to or higher than a predetermined value in a state where the controller is controlling the motor in the first control mode. When a signal output from the discriminator indicates that the rotation of the motor is abnormal, the controller stops the motor. When the signal output from the discriminator indicates that the rotation is not abnormal, the controller continues a drive of the motor.

According to one embodiment, an image forming apparatus includes a printer and a controller. The printer performs image formation on a sheet at a first speed relating to a speed of image formation or at a second speed slower than the first speed. The controller acquires information on deterioration of developer contained in an own apparatus, and controls the printer to perform image formation at the first speed when the information does not satisfy a predetermined condition indicating that the developer is deteriorated and to perform image formation at the second speed when the information satisfies the predetermined condition.

An image forming apparatus includes an image bearing member, a toner image forming unit, an intermediary transfer member, a first driving source, a second driving portion, a speed instruction value changing portion, an executing portion for executing an operation in a detecting mode in a first detection period in a first state and in a second detection period in a second state larger in frictional force than in the first state, and a setting portion. In each of the first and second detection periods, the speed instruction value of the second driving source is set at a fixed value and the speed instruction value of the first driving source is successively changed to different values, and the setting portion sets the speed instruction value of the first driving source used during the image formation on the basis of a detection result in the detecting mode.