An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, a polyester resin, and a polycarbonate resin, and the polyester resin includes the following polyester resin (1), polyester resin (1): a polyester resin having at least one selected from the group including a diol unit (B3) represented by Formula (B3), a diol unit (B5) represented by Formula (B5), a diol unit (B6) represented by Formula (B6), a diol unit (B7) represented by Formula (B7), a diol unit (B8) represented by Formula (B8), a diol unit (B9) represented by Formula (B9), a diol unit (B10) represented by Formula (B10), and a diol unit (B11) represented by Formula (B11),

##STR00001## ##STR00002## in Formula (B3), Rb.sup.113 and Rb.sup.213 each independently represent a hydrogen atom, a linear alkyl group having 1 or more and 3 or less carbon atoms, an alkoxy group having 1 or more and 4 or less carbon atoms, or a halogen atom, d represents an integer of 7 or greater and 15 or less, and Rb.sup.403, Rb.sup.503, Rb.sup.803, and Rb.sup.903 each independently represent a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B5), Ar.sup.105 represents an aryl group having 6 or more and 12 or less carbon atoms or an aralkyl group having 7 or more and 20 or less carbon atoms, Rb.sup.205 represents a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms, and Rb.sup.405, Rb.sup.505, Rb.sup.805, and Rb.sup.905 each independently represent a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B6), Rb.sup.116 and Rb.sup.216 each independently represent a hydrogen atom, a linear alkyl group having 1 or more and 3 or less carbon atoms, an alkoxy group having 1 or more and 4 or less carbon atoms, or a halogen atom, e represents an integer of 4 or greater and 6 or less, and Rb.sup.406, Rb.sup.506, Rb.sup.806, and Rb.sup.906 each independently represent a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B7), Rb.sup.407, Rb.sup.507, Rb.sup.807, and Rb.sup.907 each independently represent a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon

A bis-butadiene derivative is represented by general formula (1) shown below.

##STR00001##

In general formula (1), Ra, Rb, and Rc each represent, independently of one another, an alkyl group having a carbon number of at least 1 and no greater than 8 or an alkoxy group having a carbon number of at least 1 and no greater than 8. l and m each represent, independently of one another, an integer of at least 0 and no greater than 5. n represents an integer of at least 0 and no greater than 4. Chemical groups Ra may be the same as or different from each other. Chemical groups Rb may be the same as or different from each other. Chemical groups Rc may be the same as or different from each other.

A polyarylate resin is represented by general formula (1) shown below. In general formula (1), R.sup.1 represents a hydrogen atom or methyl group. R.sup.2 and R.sup.3 each represent a hydrogen atom or an alkyl group having a carbon number of at least 1 and no greater than 4. R.sup.2 and R.sup.3 are not the same as one another. When R.sup.1 represents a hydrogen atom, R.sup.2 and R.sup.3 are not bonded to one another. When R.sup.1 represents a methyl group, R.sup.2 and R.sup.3 are optionally bonded to one another to form a ring. r and s each represent a number greater than or equal to 0 and less than or equal to 49. t and u each represent a number greater than or equal to 1 and less than or equal to 50. r+s+t+u=100. r+t=s+u. ##STR00001##

A polyarylate resin includes repeating units represented by formulas (1), (2), and (4). The polyarylate resin further includes a repeating unit represented by formula (3) and a percentage of the number of repeats of the repeating unit represented by formula (3) relative to the total number of repeats of the respective repeating units represented by formulas (1) and (3) is greater than 0% and less than 50%. Or, the polyarylate resin does not include the repeating unit represented by formula (3).

In formula (1), R.sup.1 and R.sup.2 each represent, independently of one another, a hydrogen atom or a methyl group and X represents a divalent group represented by formula (X1) or (X2). In formula (3), R.sup.5 and R.sup.6 each represent, independently of one another, a hydrogen atom or a methyl group.

##STR00001##

An image forming apparatus includes an electrophotographic photoreceptor that has a photosensitive layer constituting a surface of the electrophotographic photoreceptor, a charging device that charges the surface of the electrophotographic photoreceptor, an electrostatic charge image forming device that forms an electrostatic charge image on the charged surface of the electrophotographic photoreceptor, a developing device that accommodates a developer containing a toner which contains toner particles and an external additive, and develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor by the developer as a toner image, a transfer device that transfers the toner image formed on the surface of the electrophotographic photoreceptor to a surface of a recording medium, and a cleaning device that includes a cleaning blade coming into contact with the surface of the electrophotographic photoreceptor and cleaning at least residual toner particles on the surface of the electrophotographic photoreceptor

An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, at least one of a polyester resin (PEz) or a polycarbonate resin (PCz) that has at least one of a structure (Z1) represented by Formula (Z1) or a structure (Z2) represented by Formula (Z2) at at least one terminal, and a resin (X) that has at least one of a unit (X1) represented by Formula (X1) or a unit (X2) represented by Formula (X2), a mass proportion of the resin (X) in a total amount of the polyester resin (PEz), the polycarbonate resin (PCz), and the resin (X) in the charge transport layer is 0.5% by mass or greater and 30% by mass or less, and the charge transport layer has an average thickness of greater than 30 ?m and less than 50 ?m,

##STR00001## in Formula (Z1), Ar.sup.1 represents an aromatic ring that may have a substituent, in Formula (Z2), Ar.sup.2 represents an aromatic ring that may have a substituent,

##STR00002## in Formula (X1), R.sup.101, R.sup.102, and R.sup.103 each independently represent a hydrogen atom or an alkyl group having 1 or more and 5 or less carbon atoms, L.sup.101 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, an aromatic ring that may have a substituent, or a combination thereof, L.sup.102 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, or a combination thereof, R.sup.104 and R.sup.105 each independently represent an alkyl group having 1 or more and 5 or less carbon atoms, n represents an integer of 0 or greater and 300 or less, R.sup.106, R.sup.107, and R.sup.108 each independently represent an alkyl group having 1 or more and 5 or less carbon atoms or O[Si(R.sup.109)(R.sup.110)O].sub.mSi(R.sup.111)(R.sup.112)(R.sup.113), R.sup.109, R.sup.110, R.sup.111, R.sup.12, and R.sup.113 each independently represent an alkyl group having 1 or more and 5 or less carbon atoms, and m represents an integer of 0 or greater and 20 or less, in Formula (X2), R.sup.201, R.sup.202, and R.sup.203 each independently represent a hydrogen atom or an alkyl group having 1 or more and 5 or less carbon atoms, L.sup.201 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, an aromatic ring that may have a substituent, or a combination thereof, L.sup.202 represents a single bond, an alkylene group having 1 or more and 5 or less carbon atoms, O, C(?O), C(?O)O, or a combination ther

An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer including a charge generation layer and a charge transport layer or a single layer type photosensitive layer that is a photosensitive layer disposed on the conductive substrate, in which the charge transport layer or the single layer type photosensitive layer is an outermost layer and contains a charge transport material and a binder resin containing a polyester resin having an aromatic ring, the charge transport layer or the single layer type photosensitive layer has an average thickness of 28 ?m or greater and 50 ?m or less, and a weight reduction ratio of the charge transport layer or the single layer type photosensitive layer from 30? C. to 175? C. in thermogravimetric analysis is 0.1% by mass or less.

An image forming apparatus includes an electrophotographic photoreceptor that has a photosensitive layer constituting a surface of the electrophotographic photoreceptor, a charging device that charges the surface of the electrophotographic photoreceptor, an electrostatic charge image forming device that forms an electrostatic charge image on the charged surface of the electrophotographic photoreceptor, a developing device that accommodates a developer containing a toner which contains toner particles and an external additive, and develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor by the developer as a toner image, a transfer device that transfers the toner image formed on the surface of the electrophotographic photoreceptor to a surface of a recording medium, and a cleaning device that includes a cleaning blade coming into contact with the surface of the electrophotographic photoreceptor and cleaning at least residual toner particles on the surface of the electrophotographic photoreceptor.

The invention relates to an electrophotographic photoreceptor which is excellent in abrasion resistance and electrical properties by using a fluororesin and a polymer containing a structure represented by a specific formula, and has a long life span, an electrophotographic photoreceptor cartridge and an image forming apparatus including the electrophotographic photoreceptor, and a dispersant which is excellent in dispersibility of a fluororesin particle, and the electrical properties, and the compatibility with a binder resin.

Provided is an electrophotographic photosensitive member that suppresses image smearing at the time of its repeated use, and expresses satisfactory wear resistance and electric characteristics. The electrophotographic photosensitive member includes a support and a photosensitive layer in the stated order, wherein a surface layer of the electrophotographic photosensitive member contains a copolymer of a hole-transportable compound having a chain-polymerizable functional group and a specific compound having maleimide groups.