Abstract: Provided is an image forming apparatus capable of improving operation performances. Sheet feeding cassettes and having sheet stacking portions SS1 and SS2 and sheet feeding portions, which are engaged and provided on the upstream side of the sheet stacking portions SS1 and SS2 in a pulling-out direction in an engaging and disengaging manner and feed the sheet stored in the sheet stacking portions SS1 and SS2, are vertically disposed at a plurality of positions in an image forming apparatus main body so that the sheet feeding cassette can be pulled out. Moreover, when the sheet feeding operation using the lower sheet feeding cassette is performed, only the sheet stacking portion SS1 of the sheet feeding cassette is pulled out, and when the sheet feeding operation stops, the sheet stacking portion SS1 and the sheet feeding portion of the sheet feeding cassette are integrally pulled out.

Abstract: An image forming apparatus includes a first detection portion at a first guide provided in an image forming unit and a second detection portion at a second guide provided in a unit drawable to the exterior of the image forming apparatus. Since there are many parts in this apparatus, an error in the relative positions of the first and the second detection portions is large. The image forming apparatus includes a lock member configured to lock the unit to an image forming apparatus main body, and a pressure member configured to, when the unit is locked to the image forming apparatus main body, press the first guide and the second guide to each other. As a result, adjustment of the relative positions of the first and the second detection portions is not required at the time of replacement of the unit or the detection portions.

Abstract: An image forming apparatus includes: an image bearing member; a transfer member; and a contact-and-separation portion. The contact-and-separation means includes: an urging member; a movement driving portion; and a controller for controlling the movement driving portion so that the transfer member is locatable at a contact position where the transfer member is contacted to the image bearing member, a first spaced position where the transfer member is spaced from the image bearing member in a state in which a load by the urging force is exerted on the movement driving portion, and a second spaced position where the transfer member is spaced from the image bearing member in a state in which the load by the urging force is not exerted on the movement driving portion.

Abstract: A belt driving apparatus includes: an endless belt having a stepped region at its edge; a driving member for driving the endless belt; a moving member for moving the endless belt in a widthwise direction; a mark provided at a part of the endless belt with respect to a circumferential direction and located at a position corresponding to the stepped region of the endless belt with respect to a rotational direction; a mark detecting member for detecting the mark during rotation of the endless belt; an edge position detecting member for detecting a widthwise position of at least one of edges of the endless belt during rotation; and a controller for controlling, after the mark detecting member detects the mark, the moving member on the basis of a detection result of the edge other than the stepped region of the endless belt.

Abstract: In a belt driving device, the width of a belt member is larger than the width of a driven roller portion in the rotation axis direction of the driven roller portion. The belt driving device includes a movement unit configured to, when a load is generated in friction members at both ends of the driven roller portion, rotate and move the friction members in a direction opposite to the moving direction of the belt member.

Abstract: In a belt driving device, the width of a belt member is larger than the width of a driven roller portion in the rotation axis direction of the driven roller portion. The belt driving device includes a movement unit configured to, when a load is generated in friction members at both ends of the driven roller portion, rotate and move the friction members in a direction opposite to the moving direction of the belt member.