Developing device, process cartridge and electrophotographic image forming apparatus

A process cartridge which is detachably attachable mounted on a body of an electrophotographic image forming apparatus, the process cartridge comprising:

• an electrophotographic photosensitive member;
• a developing member for developing the latent image formed on the electrophotographic photosensitive member;
• an exposure optical path for guiding an exposure light emitted from exposure means mounted in a body of the electrophotographic image forming apparatus to the electrophotographic photosensitive member;
• a developer containing portion for containing a developer which is used by the developing member for developing the latent image;
• a vent port for allowing air in the inside of the developer containing portion to pass therethrough;
• a first sheet member for preventing scattering of the developer into the exposure optical path, the first sheet member being disposed between the exposure optical path and the developing member and being in contact with the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member;
• a first sealing member for preventing leaking of the developer in the inside of the developer containing portion from the developer containing portion, the first sealing member being in contact with one end portion of the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member;
• and
• a second sealing member for preventing leaking of the developer in the inside of the developer containing portion from the developer containing portion, the second sealing member being in contact with another end portion of the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member.

An electrophotographic image forming apparatus for forming an image on a recording medium, the electrophotographic image forming apparatus comprising:

• (a) exposure means;
• (b) a developing device for developing a latent image formed on an electrophotographic photosensitive member used in the electrophotographic image forming apparatus, the developing device including a developing member for developing the latent image formed on the electrophotographic photosensitive member, an exposure optical path for guiding an exposure light emitted from exposure means mounted in a body of the electrophotographic image forming apparatus to the electrophotographic photosensitive member, a developer containing portion for containing a developer which is used by the developing member for developing the latent image, a vent port for allowing air in the inside of the developer containing portion to pass therethrough, a first sheet member for preventing scattering of the developer into the exposure optical path, the first sheet member being disposed between the exposure optical path and the developing member and being in contact with the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member, a first sealing member for preventing leaking of the developer in the inside of the developer containing portion from the developer containing portion, the first sealing member being in contact with one end portion of the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member, and a second sealing member for preventing leaking of the developer in the inside of the developer containing portion from the developer containing portion, the second sealing member being in contact with another end portion of the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member;
• and
• (c) conveying means for conveying the recording medium.

An electrophotographic image forming apparatus for forming an image on a recording medium on which a process cartridge can be detachably attachable mounted, the electrophotographic image forming apparatus comprising:

• (a) exposure means;
• (b) mounting means for detachably mounting the process cartridge which including an electrophotographic photosensitive member, a developing member for developing the latent image formed on the electrophotographic photosensitive member, an exposure optical path for guiding an exposure light emitted from exposure means mounted in a body of the electrophotographic image forming apparatus to the electrophotographic photosensitive member, a developer containing portion for containing a developer which is used by the developing member for developing the latent image, a vent port for allowing air in the inside of the developer containing portion to pass therethrough, a first sheet member for preventing scattering of the developer into the exposure optical path, the first sheet member being disposed between the exposure optical path and the developing member and being in contact with the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member, a first sealing member for preventing leaking of the developer in the inside of the developer containing portion from the developer containing portion, the first sealing member being in contact with one end portion of the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member, and a second sealing member for preventing leaking of the developer in the inside of the developer containing portion from the developer containing portion, the second sealing member being in contact with another end portion of the electrophotographic photosensitive member in the longitudinal direction of the electrophotographic photosensitive member;
• and
• (c) conveying means for conveying the recording medium.