Developing device used in electrophotographic field and method of producing developing roller incorporated therein

Claim 2

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; and said developing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, said pore openings having a diameter which is at most twice an average diameter of the toner particles, whereby during a rotation of said developing roller, the toner particles are captured and held by the pore openings of said developing roller to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body.

Claim 3

A developing device as set forth in claim 1, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 the 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°, and said developer layer regulating means is formed of a metal material selected from the 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 rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 7

A developing device as set forth in claim 1, wherein said conductive open-cell foam rubber 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 8

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, whereby during a rotation of said developing roller, the toner particles are captured and held by the pore openings of said developing roller to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; and the pore opening or porous cells of said developing roller being in communication with each other through fine passages formed among said porous cells, said fine passages having a diameter which is at most twice an average diameter of the toner particles.

Claim 9

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, whereby during a rotation of said developing roller, the toner particles are captured and held by the pore openings of said developing roller to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; and the pore opening or porous cells of said developing roller being in communication with each other through fine passages formed among said porous cells, said fine passages having a diameter which is at most twice an average diameter of the toner particles.

Claim 10

A developing device as set forth in claim 7, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 11

A developing device as set forth in claim 7, 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 the operating life of said electrostatic latent image carrying body can be prolonged.

Claim 12

A developing device as set forth in claim 7, 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°, and said developer layer regulating means is formed of a metal material selected from the 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 13

A developing device as set forth in claim 7, wherein said conductive open-cell foam rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 14

A developing device as set forth in claim 7, wherein said conductive open-cell foam rubber 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 15

A developing device using a one-component developer, 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 developing roller is constituted such that a work function thereof approximates that of the toner particles, so that the toner particles are charged by a triboelectrification between said developer layer regulating means and the toner particles, whereby 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 developer, 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 developing roller is constituted such that a work function thereof approximates that of the toner particles, so that the toner particles are charged by a triboelectrification between said developer layer regulating means and the toner particles, whereby 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 rubber material of which said developing roller is formed is a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, said pore openings having a diameter which is at most twice an average diameter of the toner particles so that the toner particles are captured and held by the pore openings of said developing roller.

Claim 18

A developing device as set forth in claim 14, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 19

A developing device as set forth in claim 14, 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 the operating life of said electrostatic latent image carrying body can be prolonged.

Claim 20

A developing device as set forth in claim 14, wherein said developing roller has an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from the 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 21

A developing device as set forth in claim 14, wherein said conductive open-cell foam rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 22

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 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 whereby the toner particles can be given a desired distribution.

Claim 23

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 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 whereby the toner particles can be given a desired distribution.

Claim 24

A developing device as set forth in claim 19, wherein said conductive rubber material of which said developing roller is formed is a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, said pore openings having a diameter which is at most twice an average diameter of the toner particles so that the toner particles are captured and held by the pore openings of said developing roller.

Claim 25

A developing device as set forth in claim 20, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 the 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 has an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from the 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 conductive open-cell foam rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 29

A developing device using a one-component developer, 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 to prevent the toner particles from being electrostatically adhered to said developer layer regulating means, and wherein said developing roller and said developer layer regulating means are constituted in such a manner that work functions thereof approximate that of the toner particles, so that the toner particles are charged by a charge-injection effect resulting from the application of the bias voltage to said developer layer regulating means, whereby the toner particles can be given a desired charge distribution regardless of variations of temperature and air moisture content.

Claim 30

A developing device using a one-component developer, 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 to prevent the toner particles from being electrostatically adhered to said developer layer regulating means, and wherein said developing roller and said developer layer regulating means are constituted in such a manner that work functions thereof approximate that of the toner particles, so that the toner particles are charged by a charge-injection effect resulting from the application of the bias voltage to said developer layer regulating means, whereby the toner particles can be given a desired charge distribution regardless of variations of temperature and air moisture content.

Claim 31

A developing device as set forth in claim 25, wherein said conductive rubber material of which said developing roller is formed is a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, said pore openings having a diameter which is at most twice an average diameter of the toner particles so that the toner particles are captured and held by the pore openings of said developing roller.

Claim 32

A developing device as set forth in claim 26, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 33

A developing device as set forth in claim 26, 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 the operating life of said electrostatic latent image carrying body can be prolonged.

Claim 34

A developing device as set forth in claim 26, wherein said developing roller has an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from the 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 35

A developing device as set forth in claim 26, wherein said conductive open-cell foam rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 36

A developing device using a one-component developer, 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 to prevent the toner particles from being electrostatically adhered to said developer layer regulating means, and wherein a charge-injection effect resulting from the application of the bias voltage to said developer layer regulating means and a triboelectrification between said developing roller and/or developer layer regulating means and the toner particles are utilized for charging the toner particles.

Claim 37

A developing device using a one-component developer, 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 to prevent the toner particles from being electrostatically adhered to said developer layer regulating means, and wherein a charge-injection effect resulting from the application of the bias voltage to said developer layer regulating means and a triboelectrification between said developing roller and/or developer layer regulating means and the toner particles are utilized for charging the toner particles.

Claim 38

A developing device as set forth in claim 31, wherein said conductive rubber material of which said developing roller is formed is a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, said pore openings having a diameter which is at most twice an average diameter of the toner particles so that the toner particles are captured and held by the pore openings of said developing roller.

Claim 39

A developing device as set forth in claim 32, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 40

A developing device as set forth in claim 32, 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 the operating life of said electrostatic latent image carrying body can be prolonged.

Claim 41

A developing device as set forth in claim 32, wherein said developing roller has an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from the 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 42

A developing device as set forth in claim 32, wherein said conductive open-cell foam rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 43

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 to prevent the toner particles from being electrostatically adhered to said developer layer regulating means; and when a charge-injection effect resulting from the 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 roller.

Claim 44

A developing device using a one-component developer, which device comprises: 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 the surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material by which the toner particles are entrained to form a developer layer therearound and are carried to the surface of said electrostatic latent image carrying body; 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 to prevent the toner particles from being electrostatically adhered to said developer layer regulating means; and when a charge-injection effect resulting from the 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 roller.

Claim 45

A developing device as set forth in claim 37, wherein said conductive rubber material of which said developing roller is formed is a conductive open-cell foam rubber material so that pore openings appear over a surface of said developing roller, said pore openings having a diameter which is at most twice an average diameter of the toner particles so that the toner particles are captured and held by the pore openings of said developing roller.

Claim 46

A developing device as set forth in claim 38, wherein said conductive open-cell foam rubber material of which said developing roller is formed is selected from the 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 47

A developing device as set forth in claim 38, 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 the operating life of said electrostatic latent image carrying body can be prolonged.

Claim 48

A developing device as set forth in claim 38, wherein said developing roller has an Asker C-hardness of at most 50°, preferably 35°, and said developer layer regulating means is formed of a metal material selected from the 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 49

A developing device as set forth in claim 38, wherein said conductive open-cell foam rubber material of which said developing roller is formed is a conductive open-cell foam polyurethane rubber material, whereby a resolution of a developed image can be maintained at a high level and over a long period.

Claim 50

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 51

A developing device as set forth in claim 43, 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 52

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

Claim 53

A developing device as set forth in claim 19, wherein said developer layer regulating means comprises a blade member resiliently pressed against said developing roller.

Claim 54

A developing device as set forth in claim 46, 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 55

A developing device as set forth in claim 19, wherein said developer layer regulating means comprises a roller member is resiliently pressed against said developing roller.

Claim 56

A developing device as set forth in claim 25, wherein said developer layer regulating means comprises a blade member resiliently pressed against said developing roller.

Claim 57

A developing device as set forth in claim 49, 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 58

A developing device as set forth in claim 25, wherein said developer layer regulating means comprises a roller member is resiliently pressed against said developing roller.

Claim 59

A developing device as set forth in claim 31, wherein said developer layer regulating means comprises a blade member resiliently pressed against said developing roller.

Claim 60

A developing device as set forth in claim 52, 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 61

A developing device as set forth in claim 31, wherein said developer layer regulating means comprises a roller member is resiliently pressed against said developing roller.

Claim 62

A developing device as set forth in claim 37, wherein said developer layer regulating means comprises a blade member resiliently pressed against said developing roller.

Claim 63

A developing device as set forth in claim 55, 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 64

A developing device as set forth in claim 37, wherein said developer layer regulating means comprises a roller member is resiliently pressed against said developing roller.