Image forming apparatus and process cartridge utilizing a porous charging member

摘要

There are provided an image forming apparatus in which the generation of lateral streak images due to a decrease in the in-nip discharge intensity is suppressed while at the same time the generation of spot-like images due to abnormal discharge caused by smudges on the surface of a charging member is suppressed, and a process cartridge.;The image forming apparatus and the process cartridge each has:
a charging member containing a resin particle having a plurality of pores inside thereof; anda toner in which the coverage ratio X1 of a surface of the toner with silica fine particles is 50.0 area % or more and 75.0 area % or less, and when a theoretical coverage ratio with the silica fine particles is X2, a diffusion index represented by formula 1 satisfies formula 2.
diffusion index=X1/X2  (formula 1)diffusion index≧−0.0042×X1+0.62  (formula 2)

主权项

1. An image forming apparatus comprising:
a photosensitive member; a charging member for charging the photosensitive member; an exposure member for forming an electrostatic latent image on a surface of the charged photosensitive member; and a developing member for supplying the photosensitive member on which the electrostatic latent image is formed with a toner to form a toner image on the surface of the photosensitive member, wherein: the charging member comprises an electro-conductive substrate and an electro-conductive resin layer,
the electro-conductive resin layer comprising a binder resin C and resin particles that roughen an exterior surface of the charging member,each of the resin particles having a plurality of pores inside thereof, and a surface of the charging member has a plurality of projections derived from the resin particles, and the projections are deformable, and wherein: the toner comprises toner particles, each of which contains a binder resin T and a colorant, and inorganic fine particles, the inorganic fine particles are silica fine particles, the toner contains the silica fine particles in an amount of 0.40 parts by mass or more and 1.50 parts by mass or less based on 100 parts by mass of the toner particles, the silica fine particles are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of a silicone oil based on 100 parts by mass of a silica raw material, and a fixation ratio (%) of the silicone oil on the basis of an amount of carbon is 70% or more, and a coverage ratio X1 of a surface of the toner by the silica fine particles, as determined by X-ray photoelectron spectrometer (ESCA), is 50.0 area % or more and 75.0 area % or less, and when a theoretical coverage ratio by the silica fine particles is X2, a diffusion index represented by the following formula 1 satisfies the following formula 2:
diffusion index=X1/X2  (formula 1)diffusion index≧−0.0042×X1+0.62  (formula 2).