Disclosed is a cylindrical electrophotographic photosensitive member having a region A along an outer surface and a region B along the outer surface. In this electrophotographic photosensitive member, the region A is located on an end side in an axial direction of the electrophotographic photosensitive member relative to the region B, the region A has a specific groove provided on the outer surface of the electrophotographic photosensitive member, an area ratio a1 of the groove is 65% to 100%, the region B has specific concave portions provided on the outer surface of the electrophotographic photosensitive member, and an area ratio a2 of the concave portion is 5% to 65%.

The toner has a toner matrix particle containing a crystalline polyester resin. Associated silica including two or more of primary particles is present on the surface of the toner matrix particle. The coverage with associated silica onto the toner matrix particle is 1% or more to 30% or less, and the adherence strength of associated silica to the toner matrix particle is 20% or more to 90% or less.

An image forming apparatus includes an image bearing member, a charger, a light exposure device, and a development device. The charger charges a circumferential surface of the image bearing member to a positive polarity. The light exposure device exposes the charged circumferential surface of the image bearing member to light to form an electrostatic latent image on the circumferential surface of the image bearing member. The development device supplies a toner to the electrostatic latent image through application of a developing bias. The developing bias is a voltage of an alternating current voltage superimposed on a direct current voltage. The alternating current voltage has a frequency of 4 kHz or higher and 10 kHz or lower. The image bearing member includes a conductive substrate and a photosensitive layer of a single layer. The image bearing member satisfies formula (1)

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

An electrophotographic photoreceptor includes an electroconductive substrate; and a photosensitive layer that is formed on the electroconductive substrate and that contains an inorganic oxide and a lubricant resin which contains a polycarbonate resin having a siloxane structure therein or a polyarylate resin having a siloxane structure therein. When light having a wavelength of 780 nm is irradiated onto a slurry containing 20% by mass of the inorganic oxide in a predetermined solvent to provide an inorganic oxide slurry, the inorganic oxide slurry has a light transmittance that is 80% or more. The photosensitive layer may be a negatively-charged laminate-type photosensitive layer, a monolayer type photosensitive layer, or a positively-charged laminate-type photosensitive layer. The electrophotographic photoreceptor is less worn upon long-term use, allows no filming, and can realize stable images. A method for producing the electrophotographic photoreceptor and an electrophotographic apparatus including the electrophotographic photoreceptor are disclosed.

A compound is represented by general formula (1). In general formula (1), R.sup.1 and R.sup.2 each represent, independently of one another, a hydrogen atom, a methyl group, or an ethyl group, and a sum of the number of carbon atoms of the chemical group represented by R.sup.1 and the number of carbon atoms of the chemical group represented by R.sup.2 is 2. R.sup.3 and R.sup.4 each represent, independently of one another, a hydrogen atom, a methyl group, or an ethyl group, and a sum of the number of carbon atoms of the chemical group represented by R.sup.3 and the number of carbon atoms of the chemical group represented by R.sup.1 is 2. A photosensitive layer of an electrophotographic photosensitive member contains at least a charge generating material, a hole transport material, and a binder resin. The hole transport material includes a compound represented by general formula (1) ##STR00001##

Disclosed is a cylindrical electrophotographic photosensitive member having a region A along an outer surface and a region B along the outer surface. In this electrophotographic photosensitive member, the region A is located on an end side in an axial direction of the electrophotographic photosensitive member relative to the region B, the region A has a specific groove provided on the outer surface of the electrophotographic photosensitive member, an area ratio a1 of the groove is 65% to 100%, the region B has specific concave portions provided on the outer surface of the electrophotographic photosensitive member, and an area ratio a2 of the concave portion is 5% to 65%.

An image forming apparatus includes an image bearing member, a charger, a light exposure device, a development device, a transfer belt, a primary transfer device, a secondary transfer device, and a cleaning member. The cleaning member is pressed against a circumferential surface of the image bearing member and collects residual toner remaining on the circumferential surface of the image bearing member as a result of primary transfer of a toner. The transfer belt has a surface resistivity of at least 6 Log Ω and no greater than 11 Log Ω. 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 photosensitive layer of a single layer. The image bearing member satisfies formula (1):

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

The undercoat layer contains metal particles and a polyamide resin. The metal particle has a core and a coat layer covering at least a part of the core. The core contains titanium oxide. The coat layer contains at least a metal oxide different from titanium oxide. The metal oxide different from the titanium oxide is located on the outermost surface of the metal particles. The polyamide resin has an amide bond and an alkylene group. The absorption rate of the first peak derived from the amide bond to the second peak derived from the alkylene group to the first absorbance measured by infrared spectroscopy is ≥0.70.

The present disclosure provides an electrophotographic photosensitive member that reduces the accumulation of charge and the leakage which are caused by a repeated use in a long period of time. The electrophotographic photosensitive member has a support, an undercoat layer, a charge generation layer and a charge transport layer in this order, wherein the undercoat layer contains a polyamide resin, and a titanium oxide particle, wherein the titanium oxide particle has been surfacetreated with an organosilicon compound, wherein the undercoat layer satisfies 1070, where represents a degree [%] of hydrophobicity of the titanium oxide particle which has been surfacetreated with the organosilicon compound; and the undercoat layer satisfies 0.015()0.040, where represents an average primary particle size [m] of the titanium oxide particles, and represents a weight percentage [wt %] of an Si element of the organosilicon compound with respect to the titanium oxide particle.

An image carrier unit includes an image carrier that makes a rotation and has a photosensitive layer on an outer surface, the photosensitive layer containing a binding resin and at least one type of charge transporting material and covering the surface, and a cleaning blade that has a contact part contacting the surface of the image carrier and removes residue on the surface of the image carrier accompanying the rotation of the image carrier. A photosensitive ratio of a first product to a second product is 183.0 or higher and 233.9 or lower, the first product is obtained from a weight-average molecular weight (A) of the binder resin multiplied by an added ratio (B) of the binder resin in the photosensitive layer, and the second product is obtained from a weight-average molecular weight (C) of the charge transporting material multiplied by an added ratio (D) of the charge transporting material.