An image forming apparatus includes: a main body; a first cartridge; a second cartridge; and a retaining member. The main body includes a first power-supplying part; and a second power-supplying part. The first cartridge includes a first power-receiving part. The second cartridge includes a second power-receiving part. The first and second power-receiving parts are configured to contact with the first and second power-supplying parts respectively. The retaining member is configured to retain the first and second cartridges and includes one side wall having a frame formed of a resin material and a reinforcing member formed of a metal material. A top edge of the frame is positioned lower than top edges of the first and second power-receiving parts. A top edge of the reinforcing member is positioned at a same vertical position as or lower than the top edge of the frame.

A misattachment prevention device for an image forming unit includes multiple developer containing parts that contain individual color developers, and process parts each of which is capable to be engaged with any of the developer containing parts, and forms the image forming unit for an individual color by having one of the developer containing parts engaged, wherein (c) each of the process parts is provided with an intermediate locking member guide part in a place opposing the one of the developer containing parts, and (d) the intermediate locking member guide part is provided with an intermediate locking member that is locked with a locking part formed on the one of the individual developer containing parts, protruded from the intermediate locking member guide part to a side of an apparatus main body, and locked with a locked part formed on the apparatus main body.

Upon occurrence of a paper jam at a circulation conveyer with a switching direction being set at a paper discharge guiding direction, a controller performs control of maintaining the switching direction at the paper discharge guiding direction and discharging sheets at a section of the circulation conveyer downstream of a position of the paper jam, the printing conveyer, and the paper discharger. Upon occurrence of the paper jam with the switching direction being set at a circulation guiding direction, the controller performs control of switching the switching direction to the paper discharge guiding direction after a sheet passing a switch exits the switch, and discharging the sheets at the section of the circulation conveyer downstream of the position of the paper jam, the printing conveyer, and the paper discharger.

In a cartridge, a developing roller is configured to rotate around a first rotational axis extending in a predetermined direction and to carry developer thereon, the developing roller having a first end and a second end apart from each other in the predetermined direction, a from-first-to-second direction being defined along the predetermined direction as being directed from the first end to the second end. A developing electrode is formed of a conductive material and is configured to be electrically connected to the developing roller, the developing electrode including a main part and a protruding portion protruding from the main part in the from-first-to-second direction. A detection body is formed of an insulating material and is rotatably supported by the protruding portion, the detection body including a first opening that exposes part of the protruding portion and a covering portion covering part of the protruding portion.

A controller calculates a first time period T1 and a second time period T2. The first time period T1 is defined as a time period required for conveying the end portion of the sheet, which is conveyed in a first conveyance direction E, disposed on the upstream side in the first conveyance direction E up to a reversal position A3. The second time period T2 is defined as a time period required for conveying an end portion of the reversed sheet disposed on an upstream side in a second conveyance direction R from the reversal position A3 to a branching point A1

An image heating apparatus includes a first rotatable member and a second rotatable member configured to form a nip therebetween for heating a toner image on a recording material, a rubbing rotatable member configured to rub a surface of the first rotatable member, and a cleaning brush configured to clean a surface of the rubbing rotatable member. An average interval Sm of pits and projections of the surface of the rubbing rotatable member is 10-20 m, and the cleaning brush includes fibers each having a diameter of not less than 5 m and not more than the average interval Sm.

An image forming apparatus includes an image forming device for forming a pattern image having unit images on a photosensitive member, a sensor for irradiating the pattern image with light and detecting reflected light, and a controller for controlling the image forming device to form a pattern image for printing used when printing and a pattern image for detection to be detected by the sensor on the photosensitive member. A first pattern image for printing includes a predetermined number of first unit images arranged to be spaced from each other, each of the first unit images being smaller than a predetermined size. A first pattern image for detection corresponding to the first pattern image for printing includes more than the predetermined number of the first unit images arranged to be spaced from each other.

An image forming apparatus includes a first image forming unit, a second image forming unit, and a generator. The first image forming unit forms a first image on a basis of first image data. The second image forming unit forms a light-emittable second image on a basis of second image data. The generator generates the first image data on a basis of print data, and generates the second image data to cause the second image to be overlaid on part or all of the first image.

An image forming apparatus has a main body, a belt unit configured to accommodate a belt, a belt cleaning member and an accommodating unit. The belt cleaning unit is configured to remove waste toner adhered on the belt. The accommodating unit is configured to accommodate the toner removed by the belt cleaning unit. The apparatus further includes a drum unit having a drum cleaning member, and a waste toner conveying mechanism configured to convey the waste toner to the collecting unit. The conveying mechanism has a drum-side conveying unit configured to be connected with the drum cleaning member. Communication between the drum-side conveying unit and the collecting unit is enabled in association with movement of the drum unit from the outside position to the inside position, and disabled in association with movement of the drum unit from the inside position to the outside position.

An image forming apparatus comprising: an exposing unit including: a first light source comprising a first light emitter and a first light receiver including a first electric output responsive to a received light quantity of the first light emitter; a second light source comprising a second light emitter and a second light receiver including a second electric output responsive to a received light quantity of the second light emitter; and a first light-source driver electrically connected to the first light source and the second light source. The first light-source driver includes: a first output terminal electrically connected to the first light emitter; a second output terminal electrically connected to the second light emitter; and an input terminal electrically connected to both the first electric output and the second electric output.