Electrophotographic photoreceptor, process cartridge, and image forming apparatus

1. An electrophotographic photoreceptor comprising:

a conductive substrate;

an undercoat layer on the conductive substrate,

wherein the undercoat layer contains metal titanate compound particles, an electron transporting compound, and a binder resin; and

a photosensitive layer on the undercoat layer,

wherein a total content of the metal titanate compound particles contained in the undercoat layer relative to a total content of the electron transporting compound contained in the undercoat layer is 5 mass % or more and 50 mass % or less,

wherein the electron transporting compound contains at least one perinone compound selected from the group consisting of a compound represented by general formula (1) below and a compound represented by general formula (2) below:

in general formula (1), R11, R12, R13, R14, R15, R16, R17, and R18 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group, or a halogen atom; R11 and R12 may be bonded to each other to form a ring, so may R12 and R13, and so may R13 and R14; and R15 and R16 may be bonded to each other to form a ring, so may R16 and R17, and so may R17 and R18, and

in general formula (2), R21, R22, R23, R24, R25, R26, R27, and R28 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group, or a halogen atom; R21 and R22 may be bonded to each other to form a ring, so may R22 and R23, and so may R23 and R24; and R25 and R26 may be bonded to each other to form a ring, so may R26 and R27, and so may R27 and R28.

2. The electrophotographic photoreceptor according to claim 1 , wherein the metal titanate compound particles contain at least one type of particles selected from the group consisting of strontium titanate particles, barium titanate particles, calcium titanate particles, and magnesium titanate particles.

3. The electrophotographic photoreceptor according to claim 1 , wherein the metal titanate compound particles have an average primary particle diameter of 30 nm or more and 1 μm or less.

4. The electrophotographic photoreceptor according to claim 1 , wherein a total content of the metal titanate compound particles relative to a total solid content of the undercoat layer is 5 mass % or more and 40 mass % or less.

5. The electrophotographic photoreceptor according to claim 1 , wherein a total content of the electron transporting compound relative to a total solid content of the undercoat layer is 30 mass % or more.

6. The electrophotographic photoreceptor according to claim 1 , wherein the binder resin contains polyurethane.

7. A process cartridge detachably attachable to an image forming apparatus, the process cartridge comprising the electrophotographic photoreceptor according to claim 1 .

8. An image forming apparatus comprising:

the electrophotographic photoreceptor according to claim 1 ;

a charging unit configured to charge a surface of the electrophotographic photoreceptor;

an electrostatic latent image-forming unit configured to form an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

a developing unit configured to develop the electrostatic latent image on the surface of the electrophotographic photoreceptor by using a developer containing a toner so as to form a toner image; and

a transfer unit configured to transfer the toner image onto a surface of a recording medium.

9. An electrophotographic photoreceptor comprising:

a conductive substrate;

an undercoat layer on the conductive substrate,

wherein the undercoat layer contains metal titanate compound particles, an electron transporting compound, and a binder resin; and

a photosensitive layer on the undercoat layer,

wherein a total content of the electron transporting compound relative to a total solid content of the undercoat layer is 30 mass % or more,

wherein a total content of the metal titanate compound particles contained in the undercoat layer relative to the total content of the electron transporting compound contained in the undercoat layer is 5 mass % or more and 50 mass % or less, and

wherein the electron transporting compound contains at least one perinone compound selected from the group consisting of a compound represented by general formula (1) below and a compound represented by general formula (2) below:

in general formula (1), R11, R12, R13, R14, R15, R16, R17, and R18 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group, or a halogen atom; R11 and R12 may be bonded to each other to form a ring, so may R12 and R13, and so may R13 and R14; and R15 and R16 may be bonded to each other to form a ring, so may R16 and R17, and so may R17 and R18, and

in general formula (2), R21, R22, R23, R24, R25, R26, R27, and R28 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group, or a halogen atom; R21 and R22 may be bonded to each other to form a ring, so may R22 and R23, and so may R23 and R24; and R25 and R26 may be bonded to each other to form a ring, so may R26 and R27, and so may R27 and R28.