An image forming apparatus includes an endless belt including a base layer and an electroconductive layer positioned on an inner peripheral surface side of the belt than the base layer and forming an inner peripheral surface of the belt, and a roller provided on the inner peripheral surface side of the belt and including a roller portion around which the belt is wound and which is formed of an aluminum material. The electroconductive layer contains a binder resin, an electroconductive agent, and a copper compound, and has surface resistivity of 5.0×10.sup.6Ω/□ or less. The roller includes an alumite layer forming a surface contacting the electroconductive layer.

An image forming apparatus includes a transport belt, a first intermediate transfer belt, and a second intermediate transfer belt. The transport belt is disposed along a transport path extending in a vertical direction. The transport belt is configured to transport a recording medium while coming into contact with one surface of the recording medium. The first intermediate transfer belt is configured to sandwich the recording medium together with the transport belt. An image is transferred from the first intermediate transfer belt to the recording medium. The second intermediate transfer belt is disposed above the first intermediate transfer belt. The second intermediate transfer belt is configured to sandwich, together with the transport belt, the recording medium which is in a state where the recording medium is sandwiched between the first intermediate transfer belt and the transport belt. An image being transferred from the second intermediate transfer belt to the recording medium.

An image forming apparatus includes: a medium transport path; a first image transport path that is disposed so as to oppose the medium transport path and along which an image to be formed on the medium is transported; an image forming part that forms the image and is disposed adjacent to the first image transport path; and a second image transport path that is disposed so as to oppose the medium transport path, that is located at a distance from the image forming part, and along which an image to be formed on the medium is transported, the second image transport path, the first image transport path, and the medium transport path, together surrounding the image forming part.

An image forming apparatus includes an image bearing member, an image forming portion, an endless belt, a plurality of stretching rollers including an inner roller, an outer roller, a position changing mechanism capable of changing a position of the inner roller to a first position and a second position positioned downstream of the first position with respect to a rotational direction of the endless belt, a feeding member, a feeding member driving portion, and a controller. A feeding start timing of a recording material by the feeding member depends on the position of the inner roller during transfer of a toner image onto the recording material.

An image forming apparatus includes a rotatable first coupling provided at a side surface of an engaging portion with a taper surface, and a unit detachably mountable in a second direction crossing with the first direction. The unit includes a second coupling, a driven member and a releasing member. The second coupling includes at an end portion thereof a portion-to-be-engaged engageable with the engaging portion to transmit the driving force, and the driven member receives the driving force from the second coupling. When the unit is disengaged from the main assembly, the releasing member is moved in the second direction in contact with the taper surface to move the first coupling away from the second coupling to effect disengagement between the engaging portion and the portion-to-be-engaged.

An image forming apparatus includes a movable endless belt, an image forming unit, a plurality of rollers including a first roller and a second roller, and an urging member. The urging member is provided on an inner peripheral surface side at a position which is adjacent to and upstream of the first roller and which is downstream of the second roller with respect to a movement direction of the belt. The urging member is supported at an upstream end portion thereof with respect to the movement direction of the belt and includes a first urging portion and a second urging portion at two different positions with respect to the movement direction of the belt. The first urging portion and the second urging portion urge the belt along a widthwise direction crossing the movement direction of the belt.

A driving apparatus includes an endless belt, a belt roller which engages the endless belt, a steering member and an adjustment member. The belt roller has a rotation shaft. The steering member contacts the endless belt at the inner side of the endless belt. The adjustment member is supported rotatably. The adjustment member receives a force in response to the endless belt moving in a longitudinal direction of the rotation shaft of the belt roller, and generates a pressing force that tilts the steering member via a rotational movement of the adjustment member.

A motor control apparatus includes: a switching power supply; a first motor configured to operate with a voltage from the switching power supply; and a control unit configured to control the first motor, wherein the control unit is further configured to cause the switching power supply to supply power of the switching power supply to a load other than the first motor before detecting an initial position of a rotor of the first motor using a current flowing through the first motor.

To efficiently transmit drive through couplings on one and another sides during forward rotation and reverse rotation.

When first and second couplings are brought into engagement with each other and rotated in a forward direction, first and third drive transmission surfaces are brought into contact with each other to be rotated in the forward direction while producing components of force in directions in which the first and second couplings are drawn to each other in the rotational axis direction.

When the first and second couplings are brought into engagement with each other and rotated in a reverse direction, second and fourth drive transmission surfaces are brought into contact with each other to be rotated in the reverse direction without producing components of force in directions in which the first and second couplings are separated from each other in the rotational axis direction.

An inclined flange roller is located outward of an end portion of a tension roller in the belt width direction. The inclined flange roller includes a flange surface capable of being in contact with the edge portion of a belt in a region in which the belt is wound around the tension roller and a roller surface capable of being in contact with an inner peripheral surface of the belt between the flange surface and an end portion of the tension roller in the belt width direction.