Image forming method

Claim 2

A process for developing a latent image with a developer, comprising: charging an electrophotographic photosensitive member by negative corona charging; irradiating the charged electrophotographic photosensitive member with light in order to form a latent image; forming a layer of a developer comprising a magnetic toner containing magnetic powder having a BET specific surface area between 2 to 20 m 2 /g on a member for supporting the developer; bringing the electrophotographic photosensitive member holding the latent image into contact with said developer layer, the electrophotographic photosensitive member comprising a support and an organic photoconductive material having a charge-generating layer and a charge-transporting layer and having a surface hardness of 12 to 100 g; forming a toner image on said electrophotographic photosensitive member; transferring the toner image onto a transfer material; and cleaning the electrophotographic photosensitive member having passed through the transferring step by a blade cleaning method effected by bringing a blade into contact with the electrophotographic photosensitive member such that the load applied onto the electrophotographic photosensitive member by the blade is between 1 to 100 g/cm at a static state.

Claim 3

A proces according to claim 1, wherein the charge transporting layer comprises a charge-transporting material and a binder resin having a glass transition temeperature higher than 60° C.

Claim 4

A process according to claim 2, wherein the charge-transporting layer comprises a positive hole transporting material and a binder resin selected from the group consisting of polycarbonate, polymethacrylic esters, polyallylate, polystyrene, polyester, polysulfone, styrene-acrylonitrile copolymer and styrene-methyl methacrylate copolymer.

Claim 5

a process according to claim 1, wherein the developer has a non-magnetic inorganic fine powder with a BET specific surface area between 0.5 to 500 m 2 /g in addition to the magnetic toner.

Claim 6

A process according to claim 1, wherein non-magnetic inorganic fine powder is made from an inorganic material selected form the group consisting of alumina, titanium dioxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, siliceous sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony tiroxide, magnesium oxide, ziroconium oxide, barium sulfate, barium carbonate, calcium carbonate and silica.

Claim 7

A process according to claim 5, wherein the non-magnetic inorganic fine powder is fine silica particles.

Claim 8

A process according to claim 6, wherein the fine silica particles are added to the developer in an amount between 0.1 to 3 weight %.

Claim 9

A process according to claim 1, wherein the magnetic toner contains between 10 to 70 weight % of the magnetic powder.

Claim 10

A process according to claim 1, wherein the blade is made of a polyurethane rubber.

Claim 11

A process according to claim 9, wherein the blade is made of a polyurethane rubber having a JIS rubber hardness between 50 to 90.

Claim 12

A process according to claim 1, wherein the magnetic toner and the electrophotographic photosensitive member satisfy the formula: 0.2≦W/H≦6.0, wherein W is weight % of magnetic powder in the magnetic toner and H is a hardness of the electrophotographic photosensitive member surface.

Claim 13

A process according to claim 1, wherein the magnetic powder and the electrophotographic photosensitive member satisfy the formula: 30≦SxH≦600, wherein S is the BET specific surface area of the magnetic powder and H is a hardness of the electrophotographic photosensitive member surface.

Claim 14

A process for developing a latent image with a developer, comprising: charging an electrophotographic photosensitive member by negative corona charging; irradiating the charge electrophotographic photosensitve member with light in order to form a latent image; forming a layer of a developer comprising magnetic particles containing a binder and magnetic powder having a BET specific surface area between 2 to 20 m 2 /g, and a non-magnetic or magnetic toner on a member for supporting the developer; bringing the electrophotographic photosensitive member holding the latent image into contact with said developer layer, the electrophotographic photosensitive member comprising a support, and an organic photoconductive material having a charge-generating layer and a charge-transporting layer and having a surface hardness of 12 to 100 g; forming a toner image on said electrophotographic photosenitive member; transferring the toner image onto a transfer material; and cleaning the electrophotographic photosensitive member having passed through the transferring step by a blade cleaning method effected by bringing a blade into contact with the electrophotographic photosensitive member such that the load applied onto the electrophotographic photosensitive member by the blade is between 1 to 100 g/cm at a static state.

Claim 15

A process for developing a latent image with a developer, comprising: charging an electrophotographic photosensitive member by negative corona charging; irradiating the charge electrophotographic photosensitve member with light in order to form a latent image; forming a layer of a developer comprising magnetic particles containing a binder and magnetic powder having a BET specific surface area between 2 to 20 m 2 /g, and a non-magnetic or magnetic toner on a member for supporting the developer; bringing the electrophotographic photosensitive member holding the latent image into contact with said developer layer, the electrophotographic photosensitive member comprising a support, and an organic photoconductive material having a charge-generating layer and a charge-transporting layer and having a surface hardness of 12 to 100 g; forming a toner image on said electrophotographic photosenitive member; transferring the toner image onto a transfer material; and cleaning the electrophotographic photosensitive member having passed through the transferring step by a blade cleaning method effected by bringing a blade into contact with the electrophotographic photosensitive member such that the load applied onto the electrophotographic photosensitive member by the blade is between 1 to 100 g/cm at a static state.

Claim 16

A process according to claim 13, wherein the charge-transporting layer comprises a charge-transporting material and a binder resin having a glass transition temperature higher than 60° C.

Claim 17

A process according to claim 14, wherein the charge-transporting layer comprises a positive hole transporting material and a binder resin selected from the group consisting of polycarbonate, polymethacrylic esters, polyallylate, polystyrene, polyester, polysulfone, styrene-acylonitrile copolymer and sytrene-methyl methacrylate copolymer.

Claim 18

A process according to claim 13, wherein the developer has non-magnetic inorganic fine powder with a BET specific surface area between 0.5 to 500 m 2 /g in addition to the magnetic particles and the non-magnetic or magnetic toner.

Claim 19

A process according to claim 13, wherein the non-magnetic inorganic fine powder is made from an inorganic material selected from the group consisting of alumina, titanium dioxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, siliceous sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate and silica.

Claim 20

A process according to claim 17, wherein the non-magnetic inorganic fine powder is fine silica particles.

Claim 21

A process according to claim 18, wherein the fine silica particles are added to the developer in an amount between 0.1 to 3 weight %.

Claim 22

A process according to claim 13, wherein the magnetic particles contain between 10 to 80 weight % of the magnetic powder.

Claim 23

A process according to claim 13, wherein the blade is made of a polyurethane rubber.

Claim 24

A process according to claim 21, wherein the blade is made of a polyurethane rubber having a JIS rubber hardness between 50 to 90.

Claim 25

A process according to claim 13, wherein the magnetic particles and the electrophotographic photosensitive member satisfy the formula: 0.2≦W/H≦6.0, wherein W is weight % of magnetic powder in the magnetic toner and H is a hardness of the electrophotographic photosensitive member surface.

Claim 26

A process according to claim 13, wherein the magnetic powder and the electrophotographic photosensitive member satisfy the formula: 30≦W/H≦600, wherein S is the BET specific surface area of the magnetic powder and H is a hardness of the electrophotographic photosensitive member surface.

Claim 27

The process for developing a latent image with a developer according to claim 1 including the step of forming a layer of a developer comprising a magnetic toner having a volume resistivity of 10 12 ohm cm or more on a member for supporting the developer, in which the magnetic toner contains 10 to 70 weight % of a magnetic powder having a BET specific surface area between 2 to 20 m 2 /g.

Claim 28

A process according to claim 1, wherein latent image is developed while applying a bias voltage between the electrophotographic photosensitive member and the member for supporting the developer.

Claim 29

A process according to claim 13, wherein the latent image is developed while applying a bias voltage between the electrophotographic photosensitive member and the member for supporting the developer.