Open-cell foam developing roller

Claim 2

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; and said developing roller formed of a monolithic conductive open-cell foam elastic material, an outside peripheral surface of said conductive open-cell foam elastic material thermally or chemically fused to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller.

Claim 3

A developing device as set forth in claim 1, wherein said conductive open-cell foam elastic material of which said developing roller is formed is selected from a group consisting of a conductive open-cell foam polyurethane rubber material, a conductive open-cell foam silicone rubber material, and a conductive open-cell foam acrylonitorile-butadiene rubber material.

Claim 4

A developing device as set forth in claim 1, wherein said developing roller is resiliently pressed against the surface of said electrostatic latent image carrying body, and has an Asker C-hardness of at most 50°, preferably 35°, whereby an operating life of said electrostatic latent image carrying body can be prolonged.

Claim 5

A developing device as set forth in claim 1, further comprising a developer layer regulating means provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, said developing roller having an Asker C-hardness of at most 50°, preferably 35°, said developer layer regulating means being formed of a metal material selected from a group consisting of aluminum, stainless steel, and brass, whereby variations of the developer layer thickness regulated by said developer layer regulating means can be reduced.

Claim 6

A developing device as set forth in claim 1, wherein said conductive open-cell foam elastic material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material which is neutral with regard to frictional electrification, whereby the toner particles can be given a desired charge distribution by utilizing a triboelectrification between said developing roller and the toner particles.

Claim 7

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; a developing roller formed of a monolithic conductive open-cell foam elastic material, a surface of said developing roller thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller; and a developer roller regulating means provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, wherein when the toner particles are charged by a triboelectrification between said developing roller and developer layer regulating means and the toner particles, said developing roller and developer layer regulating means are constituted in such a manner that a relationship of work functions W 1 and W 2 thereof and a work function W 3 of the toner particles is defined by the following formula: (W.sub.1 -W.sub.3)×(W.sub.2 -W.sub.3)>0 wherein the toner particles can be given a desired distribution.

Claim 8

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; a developing roller formed of a monolithic conductive open-cell foam elastic material, a surface of said developing roller thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller; and a developer roller regulating means provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, wherein when the toner particles are charged by a triboelectrification between said developing roller and developer layer regulating means and the toner particles, said developing roller and developer layer regulating means are constituted in such a manner that a relationship of work functions W 1 and W 2 thereof and a work function W 3 of the toner particles is defined by the following formula: (W.sub.1 -W.sub.3)×(W.sub.2 -W.sub.3)>0 wherein the toner particles can be given a desired distribution.

Claim 9

A developing device as set forth in claim 6, wherein said conductive open-cell foam elastic material of which said developing roller is formed is selected from a group consisting of a conductive open-cell foam polyurethane rubber material, a conductive open-cell foam silicone rubber material, and a conductive open-cell foam acrylonitorile-butadiene rubber material.

Claim 10

A developing device as set forth in claim 6, wherein said developing roller is resiliently pressed against the surface of said electrostatic latent image carrying body, and has an Asker C-hardness of at most 50°, preferably 35°, whereby an operating life of said electrostatic latent image carrying body can be prolonged.

Claim 11

A developing device as set forth in claim 6, wherein said developing roller having an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from a group consisting of aluminum, stainless steel, and brass, whereby variations of the developer layer thickness regulated by said developer layer regulating means can be reduced.

Claim 12

A developing device as set forth in claim 6, wherein said developer layer regulating means comprises a blade member resiliently pressed against said developing roller.

Claim 13

A developing device as set forth in claim 10, wherein said blade member is positioned below said developing roller to prevent a leakage of the toner particles from a space between said developing roller and a bottom of said vessel.

Claim 14

A developing device as set forth in claim 6, wherein said developer layer regulating means comprises a roller member resiliently pressed against said developing roller.

Claim 15

A developing device using a one-component developing, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; said developing roller formed of a monolithic conductive open-cell foam elastic material, a surface of said developing roller is thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller; and a developer layer regulating means is provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, wherein said developing roller is constituted so that a work function thereof approximates, preferably conforms with, that of the toner particles, and the toner particles are charged by a triboelectrification between said developer layer regulating means and the toner particles, wherein the toner particles can be given a desired charge distribution regardless of variations of temperature and air moisture content.

Claim 16

A developing device using a one-component developing, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; said developing roller formed of a monolithic conductive open-cell foam elastic material, a surface of said developing roller is thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller; and a developer layer regulating means is provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, wherein said developing roller is constituted so that a work function thereof approximates, preferably conforms with, that of the toner particles, and the toner particles are charged by a triboelectrification between said developer layer regulating means and the toner particles, wherein the toner particles can be given a desired charge distribution regardless of variations of temperature and air moisture content.

Claim 17

A developing device as set forth in claim 13, wherein said conductive open-cell foam elastic material of which said developing roller is formed is selected from a group consisting of a conductive open-cell foam polyurethane rubber material, a conductive open-cell foam silicone rubber material, and a conductive open-cell foam acrylonitorile-butadiene rubber material.

Claim 18

A developing device as set forth in claim 13, wherein said developing roller is resiliently pressed against the surface of said electrostatic latent image carrying body, and has an Asker C-hardness of at most 50°, preferably 35°, whereby an operating life of said electrostatic latent image carrying body can be prolonged.

Claim 19

A developing device as set forth in claim 13, wherein said developing roller having an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from a group consisting of aluminum, stainless steel, and brass, whereby variations of the developer layer thickness regulated by said developer layer regulating means can be reduced.

Claim 20

A developing device as set forth in claim 13, wherein said developer layer regulating means comprises a blade member resiliently pressed against said developing roller.

Claim 21

A developing device as set forth in claim 17, wherein said blade member is positioned below said developing roller to prevent a leakage of the toner particles from a space between said developing roller and a bottom of said vessel.

Claim 22

A developing device as set forth in claim 13, wherein said developer layer regulating means comprises a roller member resiliently pressed against said developing roller.

Claim 23

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; said developing roller being formed of a monolithic conductive open-cell foam elastic material, a surface of said developing roller is thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller; and a developer layer regulating means provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, wherein said developer layer regulating means is formed of a conductive material for applying a bias voltage thereto preventing the toner particles from being electrostatically adhered to said developer layer regulating means; and when a charge-injection effect regulating from an application of the bias voltage to said developer layer regulating means is utilized for charging the toner particles, a difference between the bias voltage applied to said developer layer regulating means and a developing bias voltage applied to said developing roller is less than a level at which a high electrical current or an electrical discharge occurs between said developer layer regulating means and said developing means.

Claim 24

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; said developing roller being formed of a monolithic conductive open-cell foam elastic material, a surface of said developing roller is thermally or chemically treated to prevent a penetration of the toner particles to an open-cell foam structure of said developing roller; and a developer layer regulating means provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, wherein said developer layer regulating means is formed of a conductive material for applying a bias voltage thereto preventing the toner particles from being electrostatically adhered to said developer layer regulating means; and when a charge-injection effect regulating from an application of the bias voltage to said developer layer regulating means is utilized for charging the toner particles, a difference between the bias voltage applied to said developer layer regulating means and a developing bias voltage applied to said developing roller is less than a level at which a high electrical current or an electrical discharge occurs between said developer layer regulating means and said developing means.

Claim 25

A developing device as set forth in claim 20, wherein said conductive open-cell foam elastic material of which said developing roller is formed is selected from a group consisting of a conductive open-cell foam polyurethane rubber material, a conductive open-cell foam silicone rubber material, and a conductive open-cell foam acrylonitorile-butadiene rubber material.

Claim 26

A developing device as set forth in claim 20, wherein said developing roller is resiliently pressed against the surface of said electrostatic latent image carrying body, and has an Asker C-hardness of at most 50°, preferably 35°, whereby an operating life of said electrostatic latent image carrying body can be prolonged.

Claim 27

A developing device as set forth in claim 20, wherein said developing roller having an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from a group consisting of aluminum, stainless steel, and brass, whereby variations of the developer layer thickness regulated by said developer layer regulating means can be reduced.

Claim 28

A developing device as set forth in claim 20, wherein said developer layer regulating means comprises a blade member resilient pressed against said developing roller.

Claim 29

A developing device as set forth in claim 24, wherein said blade member is positioned below said developing roller to prevent a leakage of the toner particles from a space between said developing roller and a bottom of said vessel.

Claim 30

A developing device as set forth in claim 20, wherein said developer layer regulating means comprises a roller member resiliently pressed against said developing roller.

Claim 31

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; said developing roller being formed of a monolithic conductive open-cell foam elastic material in such a manner that pore openings appear over an outside peripheral surface thereof, a size of said pore openings being smaller than that of cellular pores inside of said developing roller, to thereby prevent a penetration of the toner particles into an open-cell foam structure of said developing roller.

Claim 32

A developing device using a one-component developer, said developing device comprising: a vessel for holding a one-component developer composed of toner particles; a developing roller rotatably provided within said vessel in such a manner that a portion of said developing roller is exposed therefrom and faces a surface of an electrostatic latent image carrying body; said developing roller being formed of a monolithic conductive open-cell foam elastic material in such a manner that pore openings appear over an outside peripheral surface thereof, a size of said pore openings being smaller than that of cellular pores inside of said developing roller, to thereby prevent a penetration of the toner particles into an open-cell foam structure of said developing roller.

Claim 33

A developing device as set forth in claim 27, wherein said monolithic conductive open-cell foam elastic material of which said developing roller is formed is selected from a group consisting of a conductive open-cell foam polyurethane rubber material, a conductive open-cell foam silicon rubber material, and a conductive open-cell foam acrylonitorile-butadiene rubber material.

Claim 34

A developing device as set forth in claim 27, wherein said developing roller is resiliently pressed against the surface of said electrostatic latent image carrying body, and has an Asker C-hardness of at most 50°, preferably 35°, whereby an operating life of said electrostatic latent image carrying body can be prolonged.

Claim 35

A developing device as set forth in claim 27, further comprising a developer layer regulating means provided within said vessel and resiliently engaged with said developing roller for regulating a thickness of the developer layer formed around said developing roller, said developing roller having an Asker C-hardness of at most 50°, preferably 35°, said developer layer regulating means being formed of a metal material selected from a group consisting of aluminum, stainless steel, and brass, whereby variations of the developer layer thickness regulated by said developer layer regulating means can be reduced.

Claim 36

A developing device as set forth in claim 27, wherein said monolithic conductive pen-cell foam elastic material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material which is neutral with regard to frictional electrification, whereby the toner particles can be given a desired charge distribution by utilizing a triboelectrification between said developing roller and the toner particles.