The present disclosure provides an electrophotographic photosensitive member that can suppress a black spot and an exposure memory. The electrophotographic photosensitive member has a support, an undercoat layer and a photosensitive layer having a mono-layer structure in this order, wherein the undercoat layer contains a binder resin and strontium titanate particles; and the photosensitive layer having a mono-layer structure contains a binder resin, a charge generation material, a hole transport material and an electron transport material.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer having a single-layer structure. The photosensitive layer contains a charge generating material, an electron transport material, a polycarbonate resin, and a hole transport material. The electron transport material includes a compound having a halogen atom and represented by general formula (1), (2), (3), (4), or (5). The polycarbonate resin has a terminal group having a fluoro group and represented by general formula (10). The hole transport material includes a compound represented by general formula (20), (21), (22), (23), (24), (25), (26), or (27). A charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer is at least +6.5 C/g. The photosensitive layer has a Vickers hardness of at least 17.0 HV at 45 C. ##STR00001## ##STR00002## ##STR00003##

An image forming apparatus includes an image bearing member, a charger, and a cleaning member. The charger charges a circumferential surface of the image bearing member to a positive polarity. The cleaning member is pressed against the circumferential surface of the image bearing member and collects a toner remaining on the circumferential surface of the image bearing member. A linear pressure N of the cleaning member on the circumferential surface of the image bearing member is at least 14 N/m and no greater than 40 N/m. A rebound resilience R of the cleaning member at a temperature of 25 C. is at least 38%. The leaner pressure N and the rebound resilience R satisfy mathematical formula (1A). The image bearing member satisfies mathematical formula (1B). $\begin{array}{cc}R<13.771N^{0.4043}& \left(1A\right)\\ 0.60\frac{V}{\left(Q/S\right)\left(d/{\mathrm{.Math.}}_r.Math.{\mathrm{.Math.}}_0\right)}& \left(1B\right)\end{array}$

An electrophotographic photoreceptor that includes a conductive support; and at least a charge generation layer and a charge transport layer on the conductive support, where the charge transport layer includes at least two layers of a first charge transport layer which is an outermost layer and a second charge transport layer which is in contact with the first charge transport layer, such that the elastic deformation ratio of a binder resin A contained in the first charge transport layer is T1(%) and the elastic deformation ratio of a binder resin B contained in the second charge transport layer is T2(%) such that T1 and T2 satisfy a relationship of {0(T1T2)4}, the first charge transport layer contains a charge transport material having a molecular weight of 600 or more, and the binder resin A and the binder resin B have different monomer units from each other.

An electrophotographic photosensitive member includes a photosensitive layer of a single layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. An optical response time is 0.05 milliseconds or longer and 0.85 milliseconds or shorter. The optical response time is a time from irradiation of a surface of the photosensitive layer charged to +800 V with pulse light having a wavelength of 780 nm to decay of a surface potential of the photosensitive layer from +800 V to +400 V. The pulse light has an intensity that allows the surface potential of the photosensitive layer to decay to +200 V from +800 V after 400 milliseconds elapse from the irradiation of the surface of the photosensitive layer charged to +800 V with the pulse light. The photosensitive layer has a Martens hardness at 50 C. of at least 160 N/mm.sup.2.

An electrophotographic photoreceptor includes a conductive substrate, a charge-generating layer disposed on the conductive substrate, and a charge-transporting layer as an outermost layer disposed on the charge-generating layer and containing a binder resin and a charge-transporting material, wherein the average particle size of the crystal of the charge-transporting material is approximately from 0.1 m to 5.0 m.

An image forming apparatus includes an image bearing member and a static elimination device. The static elimination device irradiates static elimination light onto a circumferential surface of the image bearing member. The image bearing member includes a conductive substrate and a single-layer photosensitive layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The static elimination light has a wavelength of at least 600 nm and no greater than 800 nm. The photosensitive layer has an optical absorption coefficient of at least 600 cm.sup.1 and no greater than 1,500 cm.sup.1 with respect to light having a wavelength of 660 nm.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single-layer photosensitive layer and contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. A hole mobility .sub.h is at least 1.0010.sup.7 cm.sup.2/V/second and an electron mobility .sub.e is at least 4.0010.sup.8 cm.sup.2/V/second in the photosensitive layer as measured under conditions of a temperature of 23 C. and an electric field intensity of 1.5010.sup.5 V/cm. A ratio (.sub.h/.sub.e) of the hole mobility .sub.h to the electron mobility .sub.e is at least 1.0 and no greater than 50.0.

In an image forming apparatus, a cleaning member is pressed against a circumferential surface of an image bearing member and collects a toner remaining on the circumferential surface of the image bearing member. The toner has a number average roundness of 0.965 to 0.998. The toner has a D.sub.50 of 4.0 m to 7.0 m. A linear pressure of the cleaning member on the circumferential surface of the image bearing member is 10 N/m to 40 N/m. The image bearing member includes a single-layer photosensitive layer containing a charge generating material and a hole transport material. Ionization potential Ip.sub.HTM of the hole transport material and ionization potential Ip.sub.CGM of the charge generating material satisfy mathematical formula (1) Ip.sub.HTM5.30 eV, mathematical formula (2) Ip.sub.CGM5.30 eV, and mathematical formula (3) 0.09 eV|Ip.sub.HTMIp.sub.CGM|0.30 eV.

An image forming apparatus includes an image bearing member, a charger, and a cleaning member. The charger charges a circumferential surface of the image bearing member to a positive polarity. The cleaning member is pressed against the circumferential surface of the image bearing member and collects a toner remaining on the circumferential surface of the image bearing member. A linear pressure of the cleaning member on the circumferential surface of the image bearing member is at least 10 N/m and no greater than 40 N/m. The image bearing member includes a conductive substrate and a single-layer photosensitive layer. The single-layer photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The image bearing member satisfies formula (1)

[00001]$\begin{array}{cc}0.60\frac{V}{\left(Q/S\right)\left(d/{\mathrm{.Math.}}_r.Math.{\mathrm{.Math.}}_0\right)}.& \left(1\right)\end{array}$