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

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.

An electrophotographic member includes a base layer and an elastic layer on the base layer, the elastic layer including a silicone rubber, a first cation selected from the group consisting of cations of specific structures, a second cation selected from the group consisting of cations of specific structures, and an anion.

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.

An electrophotographic belt includes a base layer containing a binder resin and carbon black in the binder resin. The binder resin contains at least one resin selected from the group consisting of PEEK and PPS. A water content calculated by ((X2−X1)/X2)×100 is 0.6% where X1 is a mass of a specimen cut out of the base layer when in a nitrogen atmosphere a temperature of the specimen is increased from 30° C. to 100° C. at a rate of 20° C./min. and maintained at 100° C. for 30 min, and X2 is a mass of the specimen when in a nitrogen atmosphere the specimen is thereafter cooled from 100° C. to 30° C. at a rate of 20° C./min. and the specimen is left to stand in the air under an environment of a temperature of 23° C. and a relative humidity of 50% for 48 hours.

The present invention provides an electrophotographic photosensitive member that allows positive ghost to be reduced even in repeated use. The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member wherein an undercoat layer contains a polymerization product of a composition including a compound represented by the following formula (1). ##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 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.

An image forming apparatus includes an electrophotographic photoreceptor which includes an electroconductive substrate, an undercoat layer which is provided on the electroconductive substrate, contains a binder resin and a metal oxide particle, and has an electrostatic capacitance per unit area of from 10 pF/cm.sup.2 to 100 pF/cm.sup.2, and a photosensitive layer provided on the undercoat layer; an electrostatic latent image forming unit that forms an electrostatic latent image on a charged surface of the electrophotographic photoreceptor; and a developing unit that stores a developer containing a toner which contains toner particles of which a volume average particle diameter is from 3.0 μm to 5.5 μm, and develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor by using the developer, so as to form a toner image.