An image forming apparatus includes a rotatable image bearing member, a rotatable transfer member, a first driving source to drive the image bearing member, a second driving source to drive the transfer member, and a control. Based on a toner amount per unit area of the toner image transferred to each of a plurality of first divided regions of an in-plane of a recording material in a feeding direction, the control portion controls a driving speed of the transfer member while each of the plurality of the first divided regions passes through a transfer portion. The control portion acquires an index value correlating with a toner amount of the toner image transferred to each of a plurality of second divided regions of the first divided region in a widthwise direction, and controls the driving speed based on the index value while the first divided region passes through the transfer portion.

An image forming apparatus includes a transferred body to which a toner image is transferred, a transfer device, a contact-separation device, and circuitry. The transfer device transfers the toner image from the transferred body onto a recording medium. The contact-separation device includes a motor and drives the motor to move the transfer device away from or into contact with the transferred body. The circuitry causes the contact-separation device to move the transfer device away from or into contact with the transferred body. The circuitry moves the transfer device away from the transferred body to a first position during standby and locates the transfer device at a second position that is closer to a contact position at which the transfer device is configured to contact the transferred body than the first position in an interval between the recording medium and a succeeding recording medium.

A driving mechanism includes a first gear mechanism, a motion conversion mechanism, an actuator, and a mechanical clutch. The mechanical clutch includes an input gear that includes a plurality of engaging portions engageable with a displaced portion on a first position. The mechanical clutch switches to a connected state and a non-connected state corresponding to whether or not the engaging portions each engage with the displaced portion of the actuator. The connected state is a state where the rotational power of the first gear mechanism is transmitted to the motion conversion mechanism. The non-connected state is a state where the rotational power of the first gear mechanism is not transmitted to the motion conversion mechanism. The plurality of engaging portions are formed on a plurality of positions within a range of a default center angle less than 180 degrees in a circumferential direction of the input gear.

An image forming apparatus includes a belt unit capable of being inserted into and pulled out of the apparatus, the belt unit including a movable endless belt, a supporting frame supporting the endless belt and having an accommodating portion, a grip member which is provided on the supporting frame at a position outside the belt in a widthwise direction of the belt that is orthogonal to a moving direction of the belt and which is movable between a first position in which the grip member is projected out of the accommodating portion in a direction orthogonal to the widthwise direction and a second position in which the grip member is accommodated in the accommodating portion, and an urging member configured to urge the grip member in a direction from the second position toward the first position.

An image forming apparatus includes: an image carrying unit; a unit-to-be-moved; a pulse motor; a moving mechanism including a rotatable member provided with a member-to-be-detected; a detecting portion; an executing portion; and a controller for causing the executing portion to execute a first stop mode on the basis of detection of the detecting portion when the unit-to-be-moved is changed in position from the second or third position to the first position and to execute a second stop mode on the basis of a pulse number of a driving signal when the unit-to-be-moved is changed in position from the first or third position to the second position and when the unit-to-be-moved is changed in position from the first or second position to the third position, and for making the change at least between the second and third positions by only unidirectional rotation of the pulse motor.

A transfer device includes: an annular transfer belt including an outer surface, a toner image being transferred to the outer surface of the annular transfer belt; a transfer unit including a transfer cylinder; and a facing roller member that is in contact with an inner surface of the transfer belt, in which the transfer cylinder includes a base material, and a surface layer wound around an outer circumference of the base material, the surface layer being replaceable with respect to the base material, the transfer cylinder has a transfer region where the toner image is transferred from the transfer belt to a recording medium in a state where the recording medium is sandwiched between the transfer cylinder and the outer surface of the transfer belt, the surface layer includes an elastic layer, the surface layer has a thickness of 6.0 mm or more and 10 mm or less and an Asker C hardness of 45° or more and 65° or less, and the facing roller member faces the transfer cylinder in the transfer region.

An image forming apparatus includes an image forming portion, an endless belt and a plurality of stretching rollers. The stretching rollers includes a tiltable steering roller, a sliding member, a first stretching roller having a smallest diameter, and a second stretching roller having a largest diameter of the diameters. With respect to rotational axis directions of the stretching rollers, lengths of contact portions of the stretching rollers with the belt are shorter than a width of the belt, the length of the contact portion of the first stretching roller with the belt is a first length, the length of the contact portion of the second stretching roller with the belt is a second length shorter than the first length, and end positions of the contact portions of the first and second stretching rollers with respect to the rotational axis direction are different from each other.

An image forming apparatus includes an image bearing member, an intermediary transfer belt, a transfer roller, a metallic roller in contact with the transfer roller to form a current path through which a current flows between itself and the transfer roller. The apparatus includes a first bearing member to rotatably support the transfer roller, a holding member to movably hold the first bearing member, a first pressing member to press the first bearing member, a second bearing member movably held by the first bearing member and to rotatably support the metallic roller and a second pressing member provided between a bearing surface provided in the first bearing member and the second bearing member to press the second bearing member.

A driving force transmission device includes a drive gear, a driven gear, which includes a gear portion and a partially toothless gear portion, rotates by the gear portion meshing with the drive gear, stops rotating in response to the partially toothless gear portion facing the drive gear, a first cam member and a second cam member which operate in conjunction with the driven gear, a first elastic member for urging the first cam member, a follower member to which urging force is applied by a second elastic member and which is moved by the second cam member, and a contact portion for coming into contact with the first cam member by urging force of the first elastic member. The first cam member includes a home cam surface for coming into contact with the contact portion so that rotation of the driven gear is limited.

There is provided an image forming apparatus including: an intermediate transfer belt; a photosensitive drum; a primary transfer member; a secondary transfer member; a first backup member; a first power supply electrically connected to the primary transfer member and to the secondary transfer member; and a first resistor electrically connected to the first power supply and to the primary transfer member. A first current route, in which the first resistor, the primary transfer member, and the photosensitive drum are connected in series in that order, is connected to the first power supply and to a basis potential. A second current route, in which the secondary transfer member and the first backup member are connected in series, is connected to the first power supply and to the basis potential. The first current route is connected in parallel to the second current route.