An image forming apparatus includes a rotatable photosensitive member, an image forming portion, a cleaning device, and a controller. The cleaning device includes a blade, a rotatable brush, and an applying portion. The controller controls the applying portion so as to apply the bias to the brush so that a potential of the brush has a polarity opposite to a normal charge polarity of toner. When a tensile strength of the brush is A (cn/dtex), a thickness of the brush is B (denier), a bristle density of the brush is C (kF/inch.sup.2), a length of the brush is D (mm), and an elastic deformation rate of the surface of the photosensitive member is E (%), the following relationships are satisfied: 48(%)≤E≤60(%), and 400≤{A×B.sup.2×C/D.sup.2}≤20408.

Disclosed is a cartridge attachable to an image forming apparatus body, the cartridge including: a memory member storing information relating to the cartridge; and a supporting body having a memory mounting portion on which the memory member is mounted, the memory member having a first surface, a second surface, and a lateral surface, the first surface is provided with a contact portion connected to a body electrode portion of the body of the image forming apparatus when the cartridge is installed in the body of the image forming apparatus, the memory mounting portion has a first opposing portion opposing the second surface and a second opposing portion opposing the lateral surface when the memory member is mounted, the memory member is mounted by adhesive between the second surface and the first opposing portion and between the lateral surface and the second opposing portion.

An example lubricant application device includes a rotatable applicator to apply a lubricant from a solid lubricant source to a rotating member, a support member to support the solid lubricant source in contact with the rotatable applicator, a near-end detection member and an end detection member coupled to the support member. The near-end detection member is coupled to the support member such that it comes in contact with the rotatable applicator after a first amount of the solid lubricant source has been consumed. The end detection member is coupled to the support member such that it comes in contact with the rotatable applicator after a second amount of the solid lubricant source has been consumed.

An image forming apparatus includes first and second image forming portions and a belt. The first and second image forming portions include first and second image bearing members, and first and second transferring members, respectively. The belt nips and feeds a recording material. The first image forming portion is disposed upstream of the second image forming portion in a moving direction of the recording material, and a plurality of members including the first and second image bearing members are integrally assembled and are mountable on or dismountable from a main assembly of the image forming apparatus. A film thickness of a surface of the first image bearing member is larger than a film thickness of a surface of the second image bearing member, circumferential speed ratios or contact pressures of rotating components differ, and/or mass ratios of components of respective developers differ.

An image forming apparatus includes a housing having an opening, a cover movable between an open position and a closed position, a first photoconductive drum and a second photoconductive drum, a first exposing head having a first boss and rotatably coupled to the cover, a second exposing head having a second boss and rotatably coupled to the cover, and a cam rotatably coupled to each of the first exposing head and the second exposing head. The cam is configured to rotate each of the first exposing head and the second exposing head. The cam includes (i) a first elongated hole into which the first boss fits and extending a direction intersecting a movement direction in which the cam moves and (ii) a second elongated hole into which the second boss fits and extending in a direction intersecting the movement direction of the cam.

A driving force transmission mechanism is a mechanism for transmitting rotational force of the second rotor having a driving-side coupling to a first rotor having a driven-side coupling. The driving-side coupling includes a body and a plurality of second engaging members engaging with first engaging members of the driven-side coupling, each of the plurality of second engaging members has at an abutting point on an abutting surface of a corresponding first engaging member a first inclined surface inclined so as to be away from a rotation axis of the body from a downstream side toward an upstream side in a rotation direction of the body.

A light-emitting device includes: a first light- emitting unit that extends in one direction and has a first emission surface located along the one direction, the first emission surface emitting light; a second light-emitting unit that is located in the one direction with respect to the first light-emitting unit, that extends in the one direction, and that has a second emission surface located along the one direction, the second emission surface emitting light; a first cleaning unit that is capable of moving in the one direction and an opposite direction that is opposite to the one direction to clean the first emission surface; a second cleaning unit that is capable of moving in the one direction and the opposite direction to clean the second emission surface; and a transmission unit that extends from the first cleaning unit and the second cleaning unit in the one direction and that transmits a moving force for moving the first cleaning unit and the second cleaning unit to the first cleaning unit and the second cleaning unit.

A light-emitting device includes: a first light- emitting unit that extends in one direction and has a first emission surface located along the one direction, the first emission surface emitting light; a second light-emitting unit that is located in the one direction with respect to the first light-emitting unit, that extends in the one direction, and that has a second emission surface located along the one direction, the second emission surface emitting light; a first cleaning unit that is capable of moving in the one direction and an opposite direction that is opposite to the one direction to clean the first emission surface; a second cleaning unit that is capable of moving in the one direction and the opposite direction to clean the second emission surface; and a transmission unit that extends from the first cleaning unit and the second cleaning unit in the one direction and that transmits a moving force for moving the first cleaning unit and the second cleaning unit to the first cleaning unit and the second cleaning unit.

An image forming apparatus includes a main housing, a drawer, and a drum unit. The drawer is movable between an accommodated position at which the drawer is accommodated in the main housing and a pulled-out position at which the drawer is pulled out from the main housing. The drum unit is attachable to the drawer in a state where the drawer is located at the pulled-out position. The drum unit includes a first photosensitive drum, a second photosensitive drum, and a waste toner pipe allowing passage of waste toner from the first photosensitive drum and waste toner from the second photosensitive drum.

An image forming apparatus includes an apparatus main assembly including a panel surface 57 capable of inputting information by displaying a software numerical key portion 58 and a numerical key portion 206 comprised of a plurality of hardware keys, and is provided with a general-purpose numerical key unit 200 capable of inputting information to the apparatus main assembly. The panel surface 57 includes a plurality of software keys corresponding to the numerical key portion 206, and in a case that a “1” key 206a of the numerical key portion 206 is in an ON state, the ON state of the “1” key 206a is displayed by using a “1” key 58a corresponding to the “1” key 206a.