Electrophotographic photoreceptor, process cartridge, and image forming apparatus

1. An electrophotographic photoreceptor comprising:

a conductive substrate; and

a photosensitive layer of a single-layer type disposed on the conductive substrate, the photosensitive layer having an absorption coefficient of 0.008 or less at a wavelength of 1000 nm and containing a binder resin, a charge generating material, an electron transporting material, and a hole transporting material, the charge generating material being at least one selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment and being contained in an amount of 0.9% by weight or more and 1.8% by weight or less relative to the binder resin.

2. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer contains the charge generating material in an amount of 0.9% by weight or more and 1.5% by weight or less relative to the binder resin.

3. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer has an absorption coefficient of 0.007 or less at a wavelength of 1000 nm.

4. The electrophotographic photoreceptor according to claim 1 , wherein the charge generating material is a type V hydroxygallium phthalocyanine pigment.

5. The electrophotographic photoreceptor according to claim 1 , wherein the hole transporting material is a hole transporting material represented by general formula (1) below:

where R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 each independently represent a hydrogen atom, a alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or a phenyl group that may be substituted with a substituent selected from a alkyl group, a alkoxy group, and a halogen atom;

and m and n each independently represent 0 or 1.

6. The electrophotographic photoreceptor according to claim 5 , wherein the hole transporting material is a hole transporting material represented by general formula (1) with m and n each representing 1.

7. The electrophotographic photoreceptor according to claim 1 , wherein the electron transporting material is an electron transporting material represented by general formula (2) below:

where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group; and R 18 represents an alkyl group, a group represented by -L 19 -O—R 20 , an aryl group, or an aralkyl group, where L 19 represents an alkylene group and R 20 represents an alkyl group.

8. The electrophotographic photoreceptor according to claim 7 , wherein the electron transporting material represented by general formula (2) has R 18 representing a branched alkyl group having from 5 to 10 carbon atoms.

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

10. An image forming apparatus comprising:

the electrophotographic photoreceptor according to claim 1 ;

a charging unit that charges a surface of the electrophotographic photoreceptor;

an electrostatic latent image forming unit that forms an electrostatic latent image on a charged surface of the electrophotographic photoreceptor;

a developing unit that forms a toner image by developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor by using a developer that contains a toner; and

a transfer unit that transfers the toner image onto a surface of a recording medium.

11. An electrophotographic photoreceptor comprising:

a conductive substrate; and

a photosensitive layer of a single-layer type disposed on the conductive substrate, the photosensitive layer having an absorption coefficient of 0.008 or less at a wavelength of 1000 nm and containing a binder resin, a charge generating material, an electron transporting material, and a hole transporting material, the charge generating material being at least one selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment and being contained in an amount of 0.9% by weight or more and 1.8% by weight or less relative to the binder resin,

wherein the hole transporting material is a hole transporting material represented by general formula (1) below:

where R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 each independently represent a hydrogen atom, a alkyl group, an alkoxy group, a phenoxy group, a halogen atom, or a phenyl group that may be substituted with a substituent selected from a alkyl group, a alkoxy group, and a halogen atom;

and m and n each independently represent 0 or 1;

wherein the electron transporting material is an electron transporting material represented by general formula (2) below:

where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group; and R 18 represents an alkyl group, a group represented by -L 19 -O—R 20 , an aryl group, or an aralkyl group, where L 19 represents an alkylene group and R 20 represents an alkyl group;

a content of the hole transporting material relative to the binder resin is 60% by weight or more and 95% by weight or less;

a content of the electron transporting material relative to the binder resin is 15% by weight or more and 50% by weight or less.

12. The electrophotographic photoreceptor according to claim 11 , wherein the content of the hole transporting material relative to the binder resin is 70% by weight or more and 90 by weight or less.

13. The electrophotographic photoreceptor according to claim 11 , wherein the content of the electron transporting material relative to the binder resin is 20% by weight or more and 40% by weight or less.