An electrophotographic photoreceptor includes a conductive substrate and a single-layer photosensitive layer which is provided on the conductive substrate and contains a binder resin, at least one charge generating material selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment, a first electron transporting material defined in the specification, a second electron transporting material defined in the specification, and a hole transporting material defined in the specification, wherein a total content of all electron transporting materials is greater than or equal to 4 parts by weight with respect to 100 parts by weight of a total solid content of the photosensitive layer, and an average loss elastic modulus E of the photosensitive layer, which is obtained by measuring dynamic viscoelasticity at a temperature of from 35 C. to 50 C. and a frequency of 0.5 Hz, is less than or equal to 1.00010.sup.6.

A positively chargeable single-layer electrophotographic photosensitive member includes 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 electron transport material contains two or more compounds selected from the group consisting of compounds represented by the chemical formulas (1) to (4) below. ##STR00001##

The electrophotographic photoreceptor of the present invention at least includes a charge-generating layer, a charge-transporting layer, and a surface protective layer sequentially deposited on an electroconductive support, wherein the charge-transporting layer contains a charge-transporting material having an ionization potential (IP.sub.A); the surface protective layer contains a binder resin and a metal oxide microparticle having an ionization potential (IP.sub.B); and the ionization potential (IP.sub.A) and the ionization potential (IP.sub.B) satisfy the relationship represented by Expression (A): 0.4 eV(IP.sub.AIP.sub.B)0.4 eV.

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer contains at least a charge generating material, a hole transport material, and a binder resin. The hole transport material is a compound represented by the following general formula (1). The binder resin is a resin represented by the following general formula (2). In general formula (1), R.sub.1 and R.sub.3 each independently represent an alkyl group, an aryl group, an aralkyl group, or an alkoxy group; and R.sub.2 and R.sub.4 each independently represent an alkyl group, or an alkoxy group. In general formula (2), R.sub.23, R.sub.24, and R.sub.25 each independently represent a hydrogen atom, or a C.sub.1-4 alkyl group, at least one of R.sub.23, R.sub.24, and R.sub.25 representing a C.sub.1-4 alkyl group; p+q=1.00, and 0.35p<1,00; and n represents 2 or 3.

##STR00001##

Provided is an electrophotographic photosensitive member including a surface layer, wherein the surface layer contains a fluorine atom-containing resin particle, a binder material, and a polymer having specific structural units.

A contact charging type image forming apparatus, to which only a direct current voltage is applied, includes an electrophotographic photoreceptor that includes a conductive base material A and a photosensitive layer provided on the conductive base material A, and a charging member that includes a conductive base material B and an elastic layer provided on the conductive base material B, in which in a case where a dielectric film thickness of the electrophotographic photoreceptor is defined as L, and a resistance component of an impedance of the charging member in a range of 1 Hz or greater and 500 Hz or less, which is measured by an alternating current impedance method, is defined as R, Expression (1) is satisfied.
L<0.75log.sub.e(R)+15.79Expression(1)