The electrophotographic apparatus includes: an electrophotographic photosensitive member; a charging unit; an image-exposing unit; a charge transfer amount-sensing unit for sensing the amount of charge transferred to the electrophotographic photosensitive member; and an exposed portion potential-controlling unit for controlling the potential of each of the exposed portions of the electrophotographic photosensitive member based on a sensing result, which is obtained by charging the electrophotographic photosensitive member with the charging unit, performing image exposure with the image-exposing unit in at least one light amount weaker than a light amount in which the normalized radius of curvature R of the electrophotographic photosensitive member represented by the following equation (E1), the normalized radius of curvature being obtained by a method of measuring an EV curve, shows a minimum, and in at least two light amounts stronger than the light amount in which the normalized radius of curvature shows the minimum.

[00001]$\begin{array}{cc}R=\frac{{\left[1+{\left(\frac{\mathrm{dy}}{\mathrm{dx}}\right)}^2\right]}^{3/2}}{.Math.\frac{d^2}{{\mathrm{dx}}^2}.Math.}& \left(E1\right)\end{array}$

An electrophotographic photosensitive member includes: a support; an undercoat layer; a charge generation layer; and a charge transport layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide fine particle, and on the surface of the undercoat layer, an arithmetic mean roughness Ra and an average length Rsm of a roughness curve element both according to JIS B0601:2001 satisfy Ra≤50 nm and 0.1≤Ra/Rsm≤0.5; and the charge generation layer contains a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine pigment includes crystal particles having a crystal form exhibiting peaks at 7.4°±0.3° and 28.2°±0.3° at Bragg angles 2θ in a spectrum of X-ray diffraction using a CuKα, ray; and in a size distribution of the crystal particles, which is measured using small-angle X-ray scattering, a peak exists in a range of 20 to 50 nm, and the peak has a half-value width of 50 nm or smaller.

Provided is an electrophotographic apparatus which uses a light emitting diode array as an exposure unit and exposes a photosensitive member to a quantity of light from the LED array whose average light quantity satisfies 0.8×Emin or more and 1.1×Emin or less on condition that a normalized radius of curvature R of a normalized graph derived from the E-V curve of the photosensitive member has a minimum value of 0.24 or less, and a light quantity at the minimum value of the normalized radius of curvature R is Emin [μJ/cm.sup.2]. This electrophotographic apparatus prevents both the occurrence of image unevenness due to light quantity variation among the elements of the LED array and the generation of ghost images due to a rest potential.

Provided is an electrophotographic photosensitive member including a support, an undercoat layer, a charge-generating layer, and a charge-transporting layer in the stated order, wherein with regard to an S.sub.0, an S.sub.1, an S.sub.2, an S.sub.3, and an S.sub.4 determined by a specific procedure (A), a ratio S.sub.1/S.sub.0 is 0.34 or less, and one of the S.sub.2, the S.sub.3, or the S.sub.4 is a positive value, and the other two thereof are negative values, or two thereof are positive values, and the other one thereof is a negative value.

Provided is an electrophotographic photosensitive member having a feature in that, in a graph that is obtained by a method of measuring an EV curve, and that has a horizontal axis representing I and a vertical axis representing V, when V at I=0.500 [μJ/cm.sup.2] is represented by V.sub.r [V], a maximum value of S [V.Math.μJ/cm.sup.2] represented by S=I.Math.(V−V.sub.r) in a range of I=0.000 to 0.030 [μJ/cm.sup.2] is represented by S.sub.max [V.Math.μJ/cm.sup.2], and a product of a light amount I.sub.i [μJ/cm.sup.2] on the horizontal axis and a potential V.sub.i[V] on the vertical axis at a point of intersection between an approximate straight line in a range of I=0.000 to 0.010 [μJ/cm.sup.2] and an approximate straight line in a range of I=0.490 to 0.500 [μJ/cm.sup.2] is represented by S.sub.i=I.sub.i.Math.(V.sub.i−V.sub.r) [V.Math.μJ/cm.sup.2], a ratio of S.sub.i to S.sub.max, which is represented by AR=S.sub.i/S.sub.max, satisfies AR≤0.10.

Provided is an electrophotographic photosensitive member capable of suppressing a ghost image. The electrophotographic photosensitive member includes, in this order: a support; an intermediate layer containing metal oxide particles; and a photosensitive layer, in which the intermediate layer contains at least one kind of compound X selected from the group consisting of a compound represented by the formula (1) and a compound represented by the formula (2).

##STR00001##

An electrophotographic photoreceptor includes an intermediate layer, a photosensitive layer, and a surface protective layer, deposited in this order on an electroconductive support. The surface protective layer includes a resin and a p-type semiconductor microparticle contained in the resin. The intermediate layer includes a resin and at least one metal oxide microparticle contained in the resin. The at least one metal oxide microparticle is selected from the group consisting of untreated tin oxide particles, tin oxide particles surface-treated with organic compounds, untreated anatase titanium oxide particles, anatase titanium oxide particles surface-treated with organic compounds, untreated rutile titanium oxide particles, and rutile titanium oxide particles surface-treated with organic compounds.

An image forming apparatus includes: an electrophotographic photoreceptor that includes an electroconductive substrate, an undercoat layer which is provided on the electroconductive substrate and has electrostatic capacitance per unit area of from 2.5×10.sup.−11 F/cm.sup.2 to 2.5×10.sup.−10 F/cm.sup.2, and a photosensitive layer provided on the undercoat layer; a charging unit; an electrostatic latent image forming unit; a developing unit; an intermediate transfer member; a primary transfer unit that primarily transfers the toner image formed on the surface of the electrophotographic photoreceptor, onto the surface of an intermediate transfer member, while providing a primary transfer current value of from 80 μA to 160 μA; and a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member, onto a surface of a recording medium.

A photoconductor is provided. The photoconductor includes a support, an undercoat layer overlying the support, and a photosensitive layer overlying the undercoat layer. The undercoat layer includes a binder resin and a zinc oxide particle. The photosensitive layer includes a compound represented by the following formula (1):

##STR00001##

where each of R.sup.1 and R.sup.2 independently represents an alkyl group or an aromatic hydrocarbon group.

An electrophotographic photoconductor including a support, an undercoat layer, and a photoconductive layer, the undercoat layer and the photoconductive layer being disposed on the support in an order mentioned, wherein the undercoat layer includes zinc oxide particles, a urethane bond-containing resin, and methylethyl ketone oxime, and the undercoat layer satisfies a formula below:

10<M/L<400  (Formula)

where M is a ratio (ppm) of the methylethyl ketone oxime included in the undercoat layer, and L is an average thickness (μm) of the undercoat layer.