The present disclosure provides an electrophotographic photosensitive member having excellent dispersibility of fluorine atom-containing resin particles, and excellent durability, with an occurrence of a ghost suppressed. In the electrophotographic photosensitive member having a surface layer, the surface layer includes a fluorine atom-containing resin particle, a binder material, a charge transport substance, and a polymer A having a specific structural unit, wherein the binder material is a thermoplastic resin, and a film thickness of the surface layer is 35 μm or larger and 50 μm or smaller.

A charging roller includes a conductive support, and a roller body to rotate about the conductive support. The roller body includes a conductive elastic layer to contact the conductive support, and a conductive resin layer located around the conductive elastic layer to form a surface of the roller body. The surface has ten-point average roughness Rzjis of approximately 20 μm to 30 μm. The conductive resin layer contains polyrotaxane.

An image forming apparatus includes an image bearing member and a charging roller that charges a circumferential surface of the image bearing member to a positive polarity. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer, and satisfies formula (1) shown below. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. $\begin{array}{cc}0.60\leqq \frac{V}{\left(Q/S\right)\times \left(d/{\mathrm{.Math.}}_r.Math.{\mathrm{.Math.}}_0\right)}& \left(1\right)\end{array}$
In formula (1), Q represents a charge amount [C] of the circumferential surface of the image bearing member, S represents a charge area [m.sup.2] of the charged circumferential surface of the image bearing member, d represents a film thickness [m] of the photosensitive layer, co represents vacuum permittivity [F/m], and V represents a value calculated in accordance with formula V=V.sub.0−V.sub.r.

An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging unit, and a developing unit, wherein the charging unit has a conductive member contactable with the electrophotographic photosensitive member, and a conductive layer of the conductive member has a matrix-domain structure; at least some of the domains are exposed at the outer surface; a volume resistivity R1 of the matrix and a volume resistivity R2 of the domains satisfy specific relationship; Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy relationship G1<G2; the surface roughness Ra of the conductive member is not more than 2.00 μm; the toner has an external additive having a shape factor SF-1 of not more than 115; and A<Dms is satisfied where A is the number-average diameter of the external additive and Dms is a distance between adjacent walls between the domains.

Provided are an image bearing member; a charging member that charges the image bearing member; an exposure unit that exposes the image bearing member; a developing unit that develops an electrostatic latent image as a developer image by supplying a developer, charged to regular polarity, to the image bearing member; a transfer member that transfers the developer image to a transfer-receiving body; and a collecting member that collects a deposit on the image bearing member downstream of a transfer portion of the image bearing member at which the developer image is transferred to the transfer-receiving body by the transfer member, and upstream of a charging portion of the image bearing member charged by the charging member, in a rotation direction of the image bearing member. After transfer of the developer image to the transfer-receiving body, the developer remaining on the image bearing member is collected by the developing unit.

Provided are a charging roller excellent in charging characteristics (charging property/charge imparting property), elasticity/flexibility, durability, and filming resistance, and an image forming apparatus using the charging roller. The charging roller includes a shaft, and at least a base layer and a surface layer on an outer peripheral portion of the shaft in a radial direction, where the surface layer contains large-particle size particles and small-particle size particles having different average particle sizes and further contains hydrophilic particles; the water contact angle of the hydrophilic particles measured with a sessile drop technique is preferably more than 0 degree and 90 degrees or less and more preferably 50 degrees or more and 90 degrees or less; the large-particle size particles are large-particle size acrylic resin particles; the small-particle size particles are small-particle size acrylic resin particles; and the hydrophilic particles are hydrophilic silica particles.

An image forming apparatus comprises a spacing member provided on a rotation shaft of the charging roller, the spacing member configured to include an engaging portion that engages with the rotation member, and to be rotatable between a spaced position at which a spaced state in which the photosensitive drum and the charging roller are spaced apart is maintained, and a released position at which the spaced state is released and the photosensitive drum and the charging roller are caused to be in contact; and a cover portion provided on the rotation shaft of the charging roller, and configured to cover an end face of the spacing member so that a fitting portion of the charging roller and the spacing member is covered.

An image forming apparatus controls the number of rotations of a photosensitive drum based on information related to the use of the photosensitive drum and a suspension time in a rotation operation of rotating the photosensitive drum after a lapse of the suspension time between a first image forming operation of forming an image on a transfer material and a second image forming operation performed after the first image forming operation.

An electroconductive roll includes a core member, a rubber base material disposed around the core member, and a surface layer disposed around the rubber base material. The arithmetic mean peak curvature S.sub.pc of a surface of the surface layer is equal to or greater than 1,880 (1/mm), and is equal to or less than 14,024 (1/mm).

An electroconductive member for electrophotography has an electroconductive support and an electroconductive layer in the order mentioned. The electroconductive layer has a matrix including a crosslinked product of a first rubber, and a domain including a crosslinked product of a second rubber and an electroconductive particle. The impedance of the outer surface of the electroconductive member is 1.0×10.sup.3 to 1.0×10.sup.8Ω). 80% by number or more of domains observed at each of a total of nine 15-μm square observation regions, which are disposed at any three points in a thickness region from the outer surface to a specific depth on each of cross sections in the thickness direction at three points: the center of the electroconductive layer in the longitudinal direction and points at a specific distance from the both edges of the electroconductive layer toward the center, satisfy specific requirements.