US5057871A — Developing device having a conductive porous tone…

Claim 1

Independent Claim 211 words

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 a 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 for development of an electrostatic latent image formed thereon; a toner-removing roller rotatably provided within said vessel to be in contact with said developing roller for mechanically removing remaining toner particles not used for the development of the electrostatic latent image from said developing roller; said toner-removing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said toner-removing roller, and that a bias voltage is applied thereto to electrostatically remove said remaining toner particles from said developing roller; and said pore openings having a diameter which is less than twice an average diameter of 10 μm of the toner particles, whereby a penetration of the toner particles into said toner-removing roller is prevented.

Claim 2

Dependent Claim 211 words

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 a 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 for development of an electrostatic latent image formed thereon; a toner-removing roller rotatably provided within said vessel to be in contact with said developing roller for mechanically removing remaining toner particles not used for the development of the electrostatic latent image from said developing roller; said toner-removing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said toner-removing roller, and that a bias voltage is applied thereto to electrostatically remove said remaining toner particles from said developing roller; and said pore openings having a diameter which is less than twice an average diameter of 10 μm of the toner particles, whereby a penetration of the toner particles into said toner-removing roller is prevented.

Claim 3

Dependent Claim 73 words

A developing device as set forth in claim 1, wherein 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 of said developing roller having a diameter which is at most twice the average diameter of the toner particles, so that the toner particles are captured and held by said pore openings of said developing roller.

Claim 4

Dependent Claim 53 words

A developing device as set forth in claim 2, wherein said conductive open-cell foam rubber 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 5

Dependent Claim 51 words

A developing device as set forth in claim 2, 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 6

Dependent Claim 93 words

A developing device as set forth in claim 2, 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 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 7

Dependent Claim 50 words

A developing device as set forth in claim 2, 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 8

Dependent Claim 62 words

A developing device as set forth in claim 2, 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 9

Dependent Claim 105 words

A developing device as set forth in claim 2, 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, wherein said developing roller is constituted so that a work function thereof approximates, preferably conforms with, that of the toner particles, to avoid a triboelectrification therebetween, and 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 10

Dependent Claim 52 words

A developing device as set forth in claim 8, wherein said conductive open-cell foam rubber 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 11

Dependent Claim 51 words

A developing device as set forth in claim 8, 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 12

Dependent Claim 63 words

A developing device as set forth in claim 8, 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 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 13

Dependent Claim 50 words

A developing device as set forth in claim 8, 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 levvel and over a long period.

Claim 14

Dependent Claim 112 words

A developing device as set forth in claim 2, 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, 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 W1 and W2 thereof and a work function W3 of the toner particles is defined by a formula: (W1-W3)×(W2-W3)>0 whereby the toner particles can be given a desired distribution.

Claim 15

Dependent Claim 53 words

A developing device as set forth in claim 13, wherein said conductive open-cell foam rubber 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 16

Dependent Claim 51 words

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 17

Dependent Claim 63 words

A developing device as set forth in claim 13, 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 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 18

Dependent Claim 50 words

A developing device as set forth in claim 13, 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 19

Dependent Claim 150 words

A developing device as set forth in claim 2, 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, 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; said developing roller and said developer layer regulating means are constituted in such a manner that work functions thereof approximate, preferably conform with, that of the toner particles to avoid a triboelectrification therebetween; and the toner particles are charged by a charge injection effect resulting from 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 20

Dependent Claim 53 words

A developing device as set forth in claim 18, wherein said conductive open-cell foam rubber 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 21

Dependent Claim 51 words

A developing device as set forth in claim 18, 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 22

Dependent Claim 63 words

A developing device as set forth in claim 18, 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 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 23

Dependent Claim 50 words

A developing device as set forth in claim 18, 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 24

Dependent Claim 113 words

A developing device as set forth in claim 2, 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, 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 a charge-injection effect resulting from 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 25

Dependent Claim 53 words

A developing device as set forth in claim 23, wherein said conductive open-cell foam rubber 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

Dependent Claim 51 words

A developing device as set forth in claim 23, 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

Dependent Claim 63 words

A developing device as set forth in claim 23, 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 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

Dependent Claim 50 words

A developing device as set forth in claim 23, 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

Dependent Claim 147 words

A developing device as set forth in claim 2, 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, 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 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 30

Dependent Claim 52 words

A developing device as set forth in claim 28, wherein said conductive open-cell foam rubber 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 31

Dependent Claim 51 words

A developing device as set forth in claim 28, 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 32

Dependent Claim 63 words

A developing device as set forth in claim 28, 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 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 33

Dependent Claim 50 words

A developing device as set forth in claim 28, 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 34

Dependent Claim 219 words

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 a surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material having pore openings along its outer peripheral surface 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 for development of an electrostatic latent image formed thereon; a toner-removing roller rotatably provided within said vessel to be in contact with said developing roller for mechanically removing remaining toner particles not used for the development of the electrostatic latent image from said developing roller; said toner-removing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said toner-removing roller, and that a bias voltage is applied thereto to electrostatically feed the toner particles to the developing roller; and said pore openings of said toner-removing roller having a diameter which is less than twice an average diameter of the toner particles, whereby a penetration of the toner particles into said toner-removing roller is prevented.

Claim 35

Dependent Claim 219 words

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 a surface of an electrostatic latent image carrying body; said developing roller being formed of a conductive rubber material having pore openings along its outer peripheral surface 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 for development of an electrostatic latent image formed thereon; a toner-removing roller rotatably provided within said vessel to be in contact with said developing roller for mechanically removing remaining toner particles not used for the development of the electrostatic latent image from said developing roller; said toner-removing roller being formed of a conductive open-cell foam rubber material so that pore openings appear over a surface of said toner-removing roller, and that a bias voltage is applied thereto to electrostatically feed the toner particles to the developing roller; and said pore openings of said toner-removing roller having a diameter which is less than twice an average diameter of the toner particles, whereby a penetration of the toner particles into said toner-removing roller is prevented.

Claim 36

Dependent Claim 78 words

A developing device as set forth in claim 33, wherein said developing roller being formed of a conductive open-cell foam rubber material so that said pore openings of said developing roller appear over a surface of said developing roller, said pore openings of said developing roller having a diameter which is at most twice the average diameter of the toner particles, so that the toner particles are captured and held by said pore openings of said developing roller.

Claim 37

Dependent Claim 52 words

A developing device as set forth in claim 34, wherein said conductive open-cell foam rubber 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 38

Dependent Claim 51 words

A developing device as set forth in claim 34, 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 39

Dependent Claim 93 words

A developing device as set forth in claim 34, 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 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 40

Dependent Claim 50 words

A developing device as set forth in claim 37, 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 41

Dependent Claim 62 words

A developing device as set forth in claim 37, 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 42

Dependent Claim 105 words

A developing device as set forth in claim 34, 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, wherein said developing roller is constituted so that a work function thereof approximates, preferably conforms with, that of the toner particles, to avoid a triboelectrification therebetween, and 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 43

Dependent Claim 52 words

A developing device as set forth in claim 40, wherein said conductive open-cell foam rubber 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 44

Dependent Claim 51 words

A developing device as set forth in claim 40, 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 45

Dependent Claim 63 words

A developing device as set forth in claim 40, 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 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 46

Dependent Claim 50 words

A developing device as set forth in claim 40, 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 47

Dependent Claim 112 words

A developing device as set forth in claim 34, 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, 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 W1 and W2 thereof and a work function W3 of the toner particles is defined by a formula: [(W1-W3)](W1-W3)×[(W2-W3)](W2-W3)>0 whereby the toner particles can be given a desired distribution.

Claim 48

Dependent Claim 52 words

A developing device as set forth in claim 45, wherein said conductive open-cell foam rubber 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 49

Dependent Claim 51 words

A developing device as set forth in claim 45, 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 50

Dependent Claim 63 words

A developing device as set forth in claim 45, 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 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 51

Dependent Claim 50 words

A developing device as set forth in claim 45, 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 52

Dependent Claim 149 words

A developing device as set forth in claim 34, 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, 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; said developing roller and said developer layer regulating means are constituted in such a manner that work functions thereof approximate, preferably conform with, that of the toner particles to avoid a triboelectrification therebetween; and the toner particles are charged by a charge-injection effect resulting from 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 53

Dependent Claim 52 words

A developing device as set forth in claim 50, wherein said conductive open-cell foam rubber 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 54

Dependent Claim 51 words

A developing device as set forth in claim 50, 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 55

Dependent Claim 63 words

A developing device as set forth in claim 50, 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 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 56

Dependent Claim 50 words

A developing device as set forth in claim 50, 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 57

Dependent Claim 113 words

A developing device as set forth in claim 34, 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, 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 a charge-injection effect resulting from 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 58

Dependent Claim 52 words

A developing device as set forth in claim 55, wherein said conductive open-cell foam rubber 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 59

Dependent Claim 51 words

A developing device as set forth in claim 55, 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 60

Dependent Claim 63 words

A developing device as set forth in claim 55, 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 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 61

Dependent Claim 50 words

A developing device as set forth in claim 55, 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 62

Dependent Claim 147 words

A developing device as set forth in claim 34, 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, 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 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 63

Dependent Claim 52 words

A developing device as set forth in claim 60, wherein said conductive open-cell foam rubber 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 64

Dependent Claim 51 words

A developing device as set forth in claim 60, 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 65

Dependent Claim 63 words

A developing device as set forth in claim 60, 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 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 66

Dependent Claim 50 words

A developing device as set forth in claim 60, 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.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-10-14	1995-04-15	1995-10-15	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-10-14	1999-04-15	1999-10-15	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-10-14	2003-04-15	2003-10-15	$7700.00	Window Closed / Lapsed

Developing device having a conductive porous toner-removing roller

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