A cartridge used for forming an image on a recording material include a memory for storing information; a supporting portion provided on a first cartridge constituent member and provided with a slit for permitting insertion of the memory; and a preventing portion, provided on a second cartridge constituent member, for preventing movement of the memory inserted in the supporting portion. With respect to a direction crossing a longitudinal direction of the cartridge and crossing a thickness direction of the memory, a width of the preventing portion is smaller than a width of the memory inserted in the slit.

An electrostatic charge image developing toner includes toner particles containing a binder resin, and an external additive including silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40 and polishing agent particles.

There is provided an image forming apparatus including a main casing, an opening-closing member configured to open and close an opening on a side of the main casing and to move between an open position and a closed position, a belt unit configured to move between a first position and a second position, a drum unit configured to move between a third position and a fourth position, a developing device unit configured to move in an arrangement direction of developing rollers, and an interlock mechanism configured such that in response to a movement of the opening-closing member from the closed position to the open position, the belt unit moves from the first position to the second position and the drum unit moves from the third position to the fourth position.

A frame of an image forming apparatus includes a bottom plate provided at a bottom of the frame; first to third installing portions, provided at least three places of the bottom plate, for installing the image forming apparatus; a first recessed portion, where the first installing portion is provided, extended from the first installing portion toward an inside of the bottom plate in a planar direction of the bottom plate; a second recessed portion, where the second installing portion is provided, extended from the second installing portion toward the inside of the bottom plate in the planar direction of the bottom plate and connecting with the first recessed portion; a third recessed portion, where the third installing portion is provided, extended from the third installing portion toward the inside of the bottom plate in the planar direction of the bottom plate and connecting with the first recessed portion and the second recessed portion; and a reinforcing member, provided in a region where the first recessed portion, the second recessed portion and the third recessed portion connecting with each other, for reinforcing the bottom plate by being fastened at bottom plate portions sandwiched between respective recessed portions, the reinforcing member being smaller in area than the bottom plate.

An image forming apparatus includes an image bearing member, a developing member, a controller configured to carry out switching control between a first state in which the developing member is caused to act on the image bearing member and a second state in which the developing member is not caused to act on the image bearing member, a transfer member, and a detector configured to read density information of the recording material. The controller detects a fog density on the basis of a difference in density information between a fog non-occurrence region of a non-image region of the recording material in the second state and a fog occurable region of the non-image region of the recording material in the first state.

In a fixing device according to the disclosure, a first surface of a restriction member is inclined so that, as the first surface goes further away from a nip portion, the first surface inclines toward a direction coming closer to an edge surface of the film, and the first surface is inclined so that, as the first surface comes downstream in the conveying direction, the first surface inclines toward a direction going further away from the edge surface of the film. A second surface is inclined so that, as the second surface comes closer to a center in the rotational axis direction of the film, the second surface inclines toward a direction coming closer to a roller, and inclines in a direction going downstream in the conveying direction.

An electrostatic charge image developing toner includes toner particles containing a binder resin and a release agent and an external additive containing fatty acid metal salt particles and abrasive particles, wherein a ratio (B/A) of an isolation amount B of the abrasive particles isolated from the toner particles after an ultrasonic isolation treatment to an isolation amount A of the fatty acid metal salt particles isolated from the toner particles after the ultrasonic isolation treatment is from 0.3 to 2.0.

An image forming apparatus includes first and second heaters and a controller. The first and second heaters have a same light distribution and heat a roller of an image fixing unit. The second heater generates a less heat amount than the first heater. The controller applies a drive voltage to a heater of the heaters. When a heat amount generated by the second heater has increased to a first threshold value by the controller controlling the drive voltage, the controller switches the drive-voltage-applied heater from the second heater to the first heater. When a heat amount generated by the first heater has decreased to a second threshold value smaller than the first threshold value by the controller controlling the drive voltage, the controller switches the drive-voltage-applied heater from the first heater to the second heater.

A light scanning apparatus, including: a light source; a deflector having a rotary polygon mirror configured to deflect the light beam emitted from the light source, and a motor configured to rotate the polygon mirror; a plurality of reflecting mirrors configured to reflect the light beam to the photosensitive member; and an optical box on which the light source is mounted, wherein the optical box has an installation wall on which the deflector is installed and a support wall positioned on a side of the photosensitive member with respect to the polygon mirror, the support wall being provided with a support portion configured to support at least one reflecting mirror, a stepped portion having a plurality of steps is formed between the installation wall and the support wall, and a back surface of the stepped portion has a shape following an inside surface of the stepped portion.

An image forming apparatus includes: an image forming unit configured to perform image formation in a first mode, in which image formation is performed by a plurality of image forming stations, or a second mode, in which image formation is performed by a predetermined image forming station among the plurality of image forming stations; and a controller configured to: control the image forming unit to perform a preparation operation in accordance with color mode information; set a restricted operation state in which the controller prohibits the image formation in the first mode and permits the image formation in the second mode when any one image forming station, except for the predetermined image forming station, is incapable of performing image formation; and prevent the image forming unit from performing the preparation operation when the first mode is set as the color mode information and the restricted operation state is set.