Abstract: An image forming apparatus includes image forming portions for forming images on a photosensitive member with different color developers by developing rollers. Developing roller moving mechanisms include (i) a developing roller moving member for moving one of the developing roller between a first contacting position contacting an associated photosensitive member and a first separating position separated from the associated photosensitive member and (ii) a first driving force switch for switching between a first transmission state in which a driving force is transmitted to the developing roller moving member to move the developing roller of an image forming portion and a disconnected state in which the transmission of the driving force is disconnected. Driving forces transmitted to the developing roller moving members are supplied from first and second gear trains.

Abstract: A belt transporting device includes a belt; first and second adjustment members provided at two respective ends of a tension roller in a belt width direction orthogonal to a direction of rotation of the belt, the first and second adjustment members each being movable by receiving a force from the belt; and a link member that interlocks the movement of the first adjustment member and the movement of the second adjustment member. If the belt is laterally shifted in the belt width direction, one of the first and second adjustment members moves by receiving a force from the belt while the other is moved by the link member such that the tension roller is tilted with respect to a driving roller.

Abstract: An image forming apparatus includes first and second image forming portions, first and second gear trains, and first and second developing roller moving mechanisms. The first developing roller moving mechanism includes a first developing roller moving member for moving the developing roller of the first image forming portion toward an associated photosensitive member and a first driving force switching portion for switching between a driving force transmission state and a driving force disconnected state. The second developing roller moving mechanism includes a second developing roller moving member for moving the developing roller of the second image forming portion toward an associated photosensitive member and a second driving force switching portion for switching between a driving force transmission state and a driving force disconnected state.

Abstract: A drive transmission mechanism includes a driving coupling element having a first engaging portion and a first operating portion; and a holder having a second engaging portion and a second operating portion, wherein when the first and second engaging portion are engaged, the driving coupling element is held in a middle position to be prevented from moving therefrom to a projected position. When the driving coupling element is moved from the middle position toward a retracted position, the first and second operating portions contact each other so that the driving coupling element rotates to a second angular position where they are disengaged from each other. By the driving coupling element rotating from the first angular position to the second angular position, the driving coupling element is enabled to move to the projected position.

Abstract: A belt transporting device includes a belt; first and second adjustment members provided at two respective ends of a tension roller in a belt width direction orthogonal to a direction of rotation of the belt, the first and second adjustment members each being movable by receiving a force from the belt; and a link member that interlocks the movement of the first adjustment member and the movement of the second adjustment member. If the belt is laterally shifted in the belt width direction, one of the first and second adjustment members moves by receiving a force from the belt while the other is moved by the link member such that the tension roller is tilted with respect to a driving roller.

Abstract: A belt transporting device includes a belt; first and second adjustment members provided at two respective ends of a tension roller in a belt width direction orthogonal to a direction of rotation of the belt, the first and second adjustment members each being movable by receiving a force from the belt; and a link member that interlocks the movement of the first adjustment member and the movement of the second adjustment member. If the belt is laterally shifted in the belt width direction, one of the first and second adjustment members moves by receiving a force from the belt while the other is moved by the link member such that the tension roller is tilted with respect to a driving roller.

Abstract: A drive transmission mechanism includes a driving coupling element having a first engaging portion and a first operating portion; a holder having a second engaging portion a second operating portion; wherein when the first and second engaging portion are engaged, the driving coupling element is held in a middle position to be prevented from moving therefrom to a projected position. When the driving coupling element is moved from the middle position toward a retracted position, the first and second operating portions contact to each other so that the driving coupling element rotates to a second angular position where they are disengaged from each other. By the driving coupling element rotating from the first angular position to the second angular position, the driving coupling element is enabled to move to the projected position.

Abstract: A belt transporting device includes a belt; first and second adjustment members provided at two respective ends of a tension roller in a belt width direction orthogonal to a direction of rotation of the belt, the first and second adjustment members each being movable by receiving a force from the belt; and a link member that interlocks the movement of the first adjustment member and the movement of the second adjustment member. If the belt is laterally shifted in the belt width direction, one of the first and second adjustment members moves by receiving a force from the belt while the other is moved by the link member such that the tension roller is tilted with respect to a driving roller.