Electrophotographic photoreceptor, method for manufacturing the photoreceptor, and image forming method and apparatus using the photoreceptor

A method for preparing an electrophotographic photoreceptor, comprising:

• forming a photosensitive layer on an electroconductive substrate;
• providing a surface layer coating liquid comprising a binder resin, a filler and a solvent which can dissolve the photosensitive layer;
• and
• coating the surface layer coating liquid on the photosensitive layer using a spray coating method,
• wherein the following relationship is satisfied:
• 1.2<A/B<2.0
• wherein A represents a weight of a coated film of the surface layer per a unit area, which is prepared by directly coating the surface layer coating liquid on the electroconductive substrate by the spray coating method and then drying at room temperature for 60 minutes, and B represents a weight of the coated film of the surface layer per the unit area after the film is dried such that the solvent remains in the film in an amount not greater than 1000 ppm;
• and
• wherein the surface layer and the photosensitive layer have a continuous structure, and wherein the surface layer satisfies the following relationship:
• σ≦D/5
• wherein D represents an average of maximum thicknesses of the surface layer of from 1.0 to 8.0 in units of micrometers in 20 segments of 5 μm wide when a portion of a cross section of the photoreceptor of 100 μm wide is divided into the 20 segments, and σ represents a standard deviation of the maximum thicknesses.

An image forming apparatus comprising:

• a photoreceptor;
• a charger configured to charge the photoreceptor;
• an image irradiator configured to irradiate the photoreceptor with a light beam to form an electrostatic latent image on the photoreceptor;
• an image developer configured to develop the electrostatic latent image with a toner to form a toner image on the photoreceptor;
• and
• an image transferer configured to transfer the toner image onto a receiving material optionally via an intermediate transfer medium,
• wherein the photoreceptor comprises:
• an electroconductive substrate;
• a photosensitive layer located on the electroconductive substrate and comprising a resin;
• and
• a surface layer comprising a filler, and a binder resin, wherein the surface layer and the photosensitive layer have a continuous structure, and wherein the surface layer satisfies the following relationship:
• σ≦D/5
• wherein D represents an average of maximum thicknesses of the surface layer of from 1.0 to 8.0 in units of micrometers in 20 segments of 5 μm wide when a portion of a cross section of the photoreceptor of 100 μm wide is divided into the 20 segments, and σ represents a standard deviation of the maximum thicknesses.

A process cartridge for an image forming apparatus, comprising:

• an electrophotographic photoreceptor comprising:
• an electroconductive substrate;
• a photosensitive layer located on the electroconductive substrate and comprising a resin;
• and
• a surface layer comprising a filler, and a binder resin, wherein the surface layer and the photosensitive layer have a continuous structure, and wherein the surface layer satisfies the following relationship:
• σ≦D/5
• wherein D represents an average of maximum thicknesses of the surface layer of from 1.0 to 8.0 in units of micrometers in 20 segments of 5 μm wide when a portion of a cross section of the photoreceptor of 100 μm wide is divided into the 20 segments, and σ represents a standard deviation of the maximum thicknesses, and
• a housing containing the photoreceptor.

An image forming method comprising:

• charging a photoreceptor;
• irradiating the photoreceptor with light to form an electrostatic latent image on a surface of the photoreceptor;
• developing the electrostatic latent image with a toner to form a toner image on the photoreceptor;
• transferring the toner image onto a receiving material optionally via an intermediate transfer medium,
• wherein the photoreceptor comprises:
• an electroconductive substrate;
• a photosensitive layer located on the electroconductive substrate and comprising a resin;
• and
• a surface layer comprising a filler, and a binder resin, wherein the surface layer and the photosensitive layer have a continuous structure, and wherein the surface layer satisfies the following relationship:
• σ≦D/5
• wherein D represents an average of maximum thicknesses of the surface layer of from 1.0 to 8.0 in units of micrometers in 20 segments of 5 μm wide when a portion of a cross section of the photoreceptor of 100 μm wide is divided into the 20 segments, and σ represents a standard deviation of the maximum thicknesses.