Image forming apparatus and process cartridge

1. An image forming apparatus, comprising:

an electrophotographic photoreceptor comprising an electroconductive substrate, and a photosensitive layer and a surface protective layer disposed on the electroconductive substrate in this order;

a charging unit that charges the electrophotographic photoreceptor;

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

a developing unit that develops the electrostatic latent image formed on the electrophotographic photoreceptor using a toner to form a toner image;

a transfer unit that transfers the toner image on a transfer medium; and

a residual toner removing unit that removes the toner remaining on the electrophotographic photoreceptor after transfer of the toner image,

the surface protective layer of the electrophotographic photoreceptor having a surface free energy of from 10 mN/m to 30 mN/m, and comprising a crosslinked product of a composition comprising:

at least one compound selected from the group consisting of a compound having a guanamine structure and a compound having a melamine structure, and

at least one charge transporting material that includes at least one substituent selected from the group consisting of —OH, —OCH 3 , —NH 2 , —SH and —COOH, wherein the solid content concentration of the charge transporting material in the composition is 80% by weight or more, and wherein the solid content concentration of the at least one compound selected from the group consisting of a compound having a guanamine structure and a compound having a melamine structure in the composition is from 0.1% by weight to 5% by weight,

the toner in the developing unit comprising silica, and

the residual toner removing unit comprising a blade member including a base layer and an edge layer having a type A durometer hardness of from HsA 75 to HsA 90 at 23° C., the hardness of the edge layer being higher than the hardness of the base layer.

2. The image forming apparatus of claim 1 , wherein the charge transporting material includes from three to four substituents selected from the group consisting of —OH, —OCH 3 , —NH 2 , —SH and —COOH.

3. The image forming apparatus of claim 1 , wherein the charge transporting material is a compound represented by the following formula (I):

F—((—R 7 —X) n1 (R 8 ) n2 Y) n3   Formula (I)

wherein F is an organic group derived from a positive hole-transporting compound, R 7 and R 8 are each independently a linear or branched alkylene group having from 1 to 5 carbon atoms, n1 is 0 or 1, n2 is 0 or 1, n3 is an integer of from 1 to 4, X is an oxygen atom, NH or a sulfur atom, and Y is —OH, —OCH 3 , —NH 2 , —SH or —COOH.

4. The image forming apparatus of claim 1 , wherein the charge transporting material includes from two to four substituents selected from the group consisting of —OH, —OCH 3 , —NH 2 , —SH and —COOH.

5. The image forming apparatus of claim 1 , wherein the edge layer in the blade member of the residual toner removing unit has a type A durometer hardness of from HsA 75 to HsA 90 at 23° C., and the base layer has a type A durometer hardness of from HsA 60 to HsA 75 at 23° C.

6. The image forming apparatus of claim 1 , wherein the edge layer in the blade member of the residual toner removing unit has a modulus of repulsion elasticity of from 5% to 20%.

7. The image forming apparatus of claim 1 , wherein the base layer in the blade member of the residual toner removing unit has a modulus of repulsion elasticity of from 25% to 40%.

8. The image forming apparatus of claim 1 , wherein the toner in the developing unit has an average shape factor of from 100 to 150.

9. A process cartridge, comprising:

an electrophotographic photoreceptor; and

at least one selected from the group consisting of a residual toner removing unit that removes the toner remaining on a surface of the electrophotographic photoreceptor, a charging unit that charges the electrophotographic photoreceptor, and a developing unit that develops an electrostatic latent image formed on the electrophotographic photoreceptor using a toner to form a toner image,

the electrophotographic photoreceptor comprising an electroconductive substrate, and a photosensitive layer and a surface protective layer disposed on the electroconductive substrate in this order,

the surface protective layer of the electrophotographic photoreceptor having a surface free energy of from 10 mN/m to 30 mN/m, and comprising a crosslinked product of a composition comprising:

at least one compound selected from the group consisting of a compound having a guanamine structure and a compound having a melamine structure, and

at least one charge transporting material that includes at least one substituent selected from the group consisting of —OH, —OCH 3 , —NH 2 , —SH and —COOH, wherein the solid content concentration of the charge transporting material in the composition is 80% by weight or more, and wherein the solid content concentration of the at least one compound selected from the group consisting of a compound having a guanamine structure and a compound having a melamine structure in the composition is from 0.1% by weight to 5% by weight,

the toner in the developing unit comprising silica, and

the residual toner removing unit comprising a blade member including a base layer and an edge layer having a type A durometer hardness HsA of from 75 to 90 at 23° C., the hardness of the edge layer being higher than the hardness of the base layer.

10. The process cartridge of claim 9 , wherein the charge transporting material includes from two to four substituents selected from the group consisting of —OH, —OCH 3 , —NH 2 , —SH and —COOH.

11. The process cartridge of claim 9 , wherein the charge transporting material includes from three to four substituents selected from the group consisting of —OH, —OCH 3 , —NH 2 , —SH and —COOH.

12. The process cartridge of claim 9 , wherein the charge transporting material is a compound represented by the following formula (I):

F—((—R 7 —X) n1 (R 8 ) n2 Y) n3   (I)

wherein F is an organic group derived from a positive hole-transporting compound, R 7 and R 8 are each independently a linear or branched alkylene group having from 1 to 5 carbon atoms, n1 is 0 or 1, n2 is 0 or 1, n3 is an integer of from 1 to 4, X is an oxygen atom, NH or a sulfur atom, and Y is —OH, —OCH 3 , —NH 2 , —SH or —COOH.

13. The process cartridge of claim 9 , wherein the edge layer in the blade member of the residual toner removing unit has a type A durometer hardness of from HsA 75 to HsA 90 at 23° C., and the base layer has a type A durometer hardness of from HsA 60 to HsA 75 at 23° C.

14. The process cartridge of claim 9 , wherein the edge layer in the blade member of the residual toner removing unit has a modulus of repulsion elasticity of from 5% to 20%.

15. The process cartridge of claim 9 , wherein the base layer in the blade member of the residual toner removing unit has a modulus of repulsion elasticity of from 25% to 40%.

16. The process cartridge of claim 9 , wherein the toner in the developing unit has an average shape factor of from 100 to 150.