The belt conveyance device includes a plurality of rollers, a belt, a meandering correction part, and an adjustment part. The rollers are disposed at intervals each other and rotate around axes. The belt is disposed around the plurality of rollers and travels. The meandering correction part shifts one end portion in an axial direction of a tension roller included in the plurality of rollers in a radial direction within a predetermined range to correct a meandering of the belt. The adjustment part shifts the other end portion in the axial direction of the tension roller in the radial direction such that a position of the one end portion of the tension roller is variable under a state where the meandering of the belt is corrected.

In an electrophotographic photosensitive member, a circumferential surface has concave portions that are independent one another; each of the concave portions has an opening, a contour of the opening has an apex having an angle α of more than 0° and 90° or less on at least an upstream side of a rotational direction of the electrophotographic photosensitive member, and has a largest width in an axial direction of the electrophotographic photosensitive member of 20 μm or more and 80 μm or less, a width of the contour in the axial direction of the electrophotographic photosensitive member decreasing from a portion having the largest width toward the apex, when viewing each of the concave portions in the axial direction, each of the concave portions has a depth that decreases from a deepest point of each of the concave portions toward the apex.

A contact-separation mechanism includes a cam to rotate to move a contact-separation member to and from a counterpart member, a detection target to rotate together with the cam, and a detector to detect presence or absence of the detection target in a detection area of the detector, and circuitry. The cam has a reference range. The circuitry issues a rotation stop instruction of the cam after a target time elapses from passing of the reference range of the detection target through the detection area, and sets the target time based on a duration of an immediately preceding passing of the reference range through the detection area.

An electrophotographic belt including: a base layer, an elastic layer formed on the base layer, and a surface layer formed on the elastic layer. The surface layer contains a binder resin and polytetrafluoroethylene particles. A content of the polytetrafluoroethylene particles is 200 parts by mass or more with respect to 100 parts by mass of the binder resin. The polytetrafluoroethylene particles have a number average particle diameter of 200 nm or less.

The belt conveyance device includes a plurality of rollers, a belt, a meandering correction part, and an adjustment part. The rollers are disposed at intervals each other and rotate around axes. The belt is disposed around the plurality of rollers and travels. The meandering correction part shifts one end portion in an axial direction of a tension roller included in the plurality of rollers in a radial direction within a predetermined range to correct a meandering of the belt. The adjustment part shifts the other end portion in the axial direction of the tension roller in the radial direction such that a position of the one end portion of the tension roller is variable under a state where the meandering of the belt is corrected.

An electrophotographic belt including: a base layer, an elastic layer formed on the base layer, and a surface layer formed on the elastic layer. The surface layer contains a binder resin and polytetrafluoroethylene particles. A content of the polytetrafluoroethylene particles is 200 parts by mass or more with respect to 100 parts by mass of the binder resin. The polytetrafluoroethylene particles have a number average particle diameter of 200 nm or less.

In one example, an apparatus includes a plate configured to pivot about a pivot point, a pulley coupled to a first planar side of the plate and configured to rotate a belt, a motor coupled to the first planar side of the plate and configured to drive the pulley, and a torsion spring coupled to a second planar side of the plate that is opposite the first planar side and configured to apply tension to the belt.

A contact-separation mechanism includes a cam to rotate to move a contact-separation member to and from a counterpart member, a detection target to rotate together with the cam, and a detector to detect presence or absence of the detection target in a detection area of the detector, and circuitry. The cam has a reference range. The circuitry issues a rotation stop instruction of the cam after a target time elapses from passing of the reference range of the detection target through the detection area, and sets the target time based on a duration of an immediately preceding passing of the reference range through the detection area.

A process cartridge using an image forming apparatus, including a rotatable image bearing member having a circumferential surface; a developing unit configured to supply a developing agent to the image bearing member; and a cleaning member that cleans the circumferential surface, wherein the developing agent contains a toner including toner particles and a metal soap, the image bearing member includes a plurality of grooves formed on the circumferential surface to extend in a circumferential direction of the circumferential surface and to be arranged side by side in a rotation axis direction, and the plurality of grooves and portions between the grooves form concave-convex portions on the circumferential surface. The circumferential surface of the image bearing member had surface roughness Rz of 0<Rz0.70 m and average interval Sm between concave-convex portions on the circumferential surface of 0<Sm70.0 m.

An image forming apparatus includes an electrophotographic photoreceptor that includes a conductive substrate and a photosensitive layer disposed on the conductive substrate, the electrophotographic photoreceptor having an outermost surface layer that contains a binder resin, a charge-transporting material, and a fluorine-containing resin particle, the fluorine-containing resin particle containing 0 or more and 30 or less carboxy groups per 10.sup.6 carbon atoms, a charging device that charges the electrophotographic photoreceptor, an electrostatic latent image forming device that forms an electrostatic latent image on the electrophotographic photoreceptor that is charged, a developing device that houses a developer containing a toner and that develops, with the developer, the electrostatic latent image formed on the electrophotographic photoreceptor into a toner image, a transfer device that transfers the toner image onto a transfer-receiving medium, and an optical discharging device that, after the toner image is transferred onto the transfer-receiving medium and before the electrophotographic photoreceptor is charged, irradiates the electrophotographic photoreceptor with discharging light with a light quantity of 1.0 ?W or more and 50.0 ?W or less to perform discharging.