A photosensitive drum rotates about a first axis extending in a first direction. A photosensitive drum is located at one end portion of a housing in a second direction. A cleaning roller cleans a surface of the photosensitive drum. The cleaning roller rotates about a second axis extending in the first direction. A cleaning electrode is electrically connected to the cleaning roller. The cleaning electrode is located at an outer surface of the housing in the first direction. The cleaning electrode is located at a tip end of the one end portion of the housing in the second direction. The cleaning electrode includes a contact surface and a guide surface. The contact surface contacts an electrical contact to which a voltage is supplied. The contact surface is perpendicular to the first direction. The guide surface guides the electrical contact to the contact surface when the drum cartridge is mounted.

An image forming apparatus includes an image forming device, an image bearer, at least one density sensor, a cleaning jig, and an insertion port. The image forming device forms a toner image. The image bearer bears the toner image to be transferred on a recording medium. The density sensor has a light-receiving surface to optically read the toner image. The light-receiving surface faces the image bearer constantly. The cleaning jig cleans the density sensor and includes a cleaner to contact the light-receiving surface. The cleaning jig is inserted through the insertion port into the body of the image forming apparatus and reciprocally moved to clean the light-receiving surface and is removed from the body of the image forming apparatus after the light-receiving surface is cleaned.

A photosensitive drum rotates about a first axis extending in a first direction. A photosensitive drum is located at one end portion of a housing in a second direction. A cleaning roller cleans a surface of the photosensitive drum. The cleaning roller rotates about a second axis extending in the first direction. A cleaning electrode is electrically connected to the cleaning roller. The cleaning electrode is located at an outer surface of the housing in the first direction. The cleaning electrode is located at a tip end of the one end portion of the housing in the second direction. The cleaning electrode includes a contact surface and a guide surface. The contact surface contacts an electrical contact to which a voltage is supplied. The contact surface is perpendicular to the first direction. The guide surface guides the electrical contact to the contact surface when the drum cartridge is mounted.

A toner conveying device includes a case, a conveying screw, a film member and a supporting member. The conveying screw conveys a toner stored in the case in a predetermined direction inside the case. The film member includes a base part elongated in an axial direction of the conveying screw as a longitudinal direction and a plurality of protruding pieces formed so as to protrude in one direction intersecting the longitudinal direction from the base part, and has flexibility. The supporting member includes an attaching part elongated in the axial direction as the longitudinal direction to which the film member is attached, and an axis part being in parallel to the longitudinal direction. The film member and the supporting member are disposed at an upper side of the conveying screw so that the protruding pieces come into contact with the conveying screw, and are rotatable around the axis part.

In a case where a cleaning member is reciprocated in a longitudinal direction of a transmissive member in cleaning operation, the time necessary for the cleaning operation is lengthened. A movement unit is controlled to move the cleaning member in a first direction from a first position in response to a cleaning start signal and then to stop the cleaning member at a second position, and to move the cleaning member in a second direction opposite to the first direction from the second position in response to a next cleaning start signal and then to stop the cleaning member at the first position.

A toner conveying device includes a case, a conveying screw, a film member and a supporting member. The conveying screw conveys a toner stored in the case in a predetermined direction inside the case. The film member includes a base part elongated in an axial direction of the conveying screw as a longitudinal direction and a plurality of protruding pieces formed so as to protrude in one direction intersecting the longitudinal direction from the base part, and has flexibility. The supporting member includes an attaching part elongated in the axial direction as the longitudinal direction to which the film member is attached, and an axis part being in parallel to the longitudinal direction. The film member and the supporting member are disposed at an upper side of the conveying screw so that the protruding pieces come into contact with the conveying screw, and are rotatable around the axis part.

In a case where a cleaning member is reciprocated in a longitudinal direction of a transmissive member in cleaning operation, the time necessary for the cleaning operation is lengthened. A movement unit is controlled to move the cleaning member in a first direction from a first position in response to a cleaning start signal and then to stop the cleaning member at a second position, and to move the cleaning member in a second direction opposite to the first direction from the second position in response to a next cleaning start signal and then to stop the cleaning member at the first position.

A cleaning member includes plural bristles including tips that come into contact with an object to be cleaned having a surface including recesses and projections; and a brush base to which the bristles are attached. The bristles each have a non-circular cross-section including a projecting portion that projects toward an outer periphery, at least the projecting portion having a size such that the projecting portion is capable of entering the recesses in the object to be cleaned.

A paper dust collecting member removes and collects paper dust attached to a conveying roller, and is attachable along the attaching direction parallel to the axial direction of the conveying roller via an opening portion provided in a side plate of an apparatus main body. The paper dust collecting member has a removing member and a holding member. The removing member removes paper dust attached to the conveying roller. The holding member holds the removing member. The holding member includes a protrusion portion which is disposed, on its distal end portion side, along a side surface of the removing member and which protrudes in the thickness direction of the removing member beyond a contact surface of the removing member.

A sheet characteristic detection device includes: a detector that is disposed on a sheet ejection path through which a sheet is ejected and that detects an electrical resistance value of the sheet; and a charge neutralizer that is disposed on a downstream side of the detector on the sheet ejection path and that neutralizes electric charge on the sheet.