Electrophotographic photoreceptor, processes for producing the same, process cartridge, and electrophotographic apparatus

A process for producing an electrophotographic photoreceptor in which an interlayer and a photosensitive layer are formed over an electroconductive substrate, the process comprising the steps of:

• surface-treating fine metal oxide particles with at least one coupling agent selected from the group consisting of silane coupling agents, titanate coupling agents, and aluminate coupling agents;
• heat-treating the surface-treated fine metal oxide particles at 180° C. or higher;
• adding the heat-treated fine metal oxide particles and a binder resin to a given solvent to thereby obtain a coating fluid;
• applying the coating fluid to an electroconductive substrate;
• and
• drying the coating fluid applied;
• to thereby obtain the interlayer, wherein a volume resistivity thereof is in a range of from 108 to 1013 Ω·cm when an electric field of 106 V/m is applied thereto at 28° C. and 85% RH, and the volume resistivity thereof at a time when an electric field of 106 V/m is applied thereto at 15° C. and 15% RH is not more than 500 times of the volume resistivity thereof at a time when an electric field of 106 V/m is applied thereto at 28° C. and 85% RH, and forming the photosensitive layer on the interlayer.

A process for producing an electrophotographic photoreceptor in which an interlayer and a photosensitive layer are formed over an electroconductive substrate, the process comprising the steps of:

• surface-treating fine metal oxide particles with a treating liquid comprising a given solvent and at least one coupling agent selected from the group consisting of silane coupling agents, titanate coupling agents, and aluminate coupling agents;
• heat-treating the surface-treated fine metal oxide particles at a first heat treatment temperature;
• heat-treating at a second heat treatment temperature the fine metal oxide particles, which have been heat-treated at the first heat treatment temperature;
• adding the fine metal oxide particles heat-treated at the second heat treatment temperature and a binder resin to a given solvent to thereby obtain a coating fluid,
• applying the coating fluid to an electroconductive substrate;
• and
• drying the coating fluid applied,
• to thereby obtain the interlayer, wherein a volume resistivity thereof is in a range of from 108 to 10−3 Ω·cm when an electric field of 106 V/m is applied thereto at 28° C. and 85% RH, and the volume resistivity thereof at a time when an electric field of 106 V/m is applied thereto at 15° C. and 15% RH is not more than 500 times of the volume resistivity thereof at a time when an electric field of 106 V/m is applied thereto at 28° C. and 85% RH, and
• forming the photosensitive layer on the interlayer.

A process cartridge comprising:

• an electrophotographic photoreceptor;
• and
• at least one of a charging unit, a development unit, a cleaning unit, an erase unit, and a transfer unit,
• wherein the electrophotographic photoreceptor is integrally formed with the at least one of the charging unit, the devepment unit, the cleaning unit, the erase unit, and the transfer unit;
• wherein the electrophotographic photoreceptor comprises an electroconductive substrate, an interlayer formed on the substrate, and a photosensitive layer formed on the interlayer;
• wherein the interlayer comprises fine metal oxide particles and a binder resin;
• and
• wherein the interlayer has a volume resistivity in a range of from 108 to 1013 Ω·cm, when electric field of 106 V/m is applied thereto at 28° C. and 85% RH;
• wherein the volume resistivity of the interlayer at a time when an electric field of 106 V/m is applied thereto at 15° C. and 15% RH is not higher than 500 times of the volume resistivity thereof at a time when an electric field of 106 V/M is applied thereto at 28° C. and 85% RH;
• and
• wherein the process cartridge can be freely attached to and removed from a main body of an electrophotographic apparatus.

An electrophotographic apparatus comprising

• an electrophotographic photoreceptor;
• a charging unit for charging the electrophotographic photoreceptor;
• an exposure unit for exposing the electrophotographic photoreceptor charged by the charging unit to form an electrostatic latent image;
• a development unit for developing the electrostatic latent image with a toner to form a toner image;
• and
• a transfer unit for transferring the toner image to a receiving medium,
• wherein the electrophotographic photoreceptor comprises an electroconductive substrate, an interlayer formed on the substrate, and a photosensitive layer formed on the interlayer;
• wherein the interlayer has a volume resistivity in a range of from 108 to 1013 Ω·cm, when electric field of 106 V/m is applied thereto at 28° C. and 85% RH;
• and
• wherein the volume resistivity of the interlayer at a time when an electric field of 106 V/m is applied thereto at 15° C. and 15% RH is not higher than 500 times of the volume resistivity thereof at a time when an electric field of 106 V/M is applied thereto at 28° C. and 85% RH.