Patent US4610531A successfully refreshed from Google Patents.
US4610531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developing method and apparatus
Assignee: Canon Inc
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Filing: 1984-08-27
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Granted: 1986-09-09
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Expires: 2004-08-27
Abstract
Abstract A method of development including the steps of forming a thin layer of developer on a surface of a developer carrying member; opposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; and intermittently forming an alternating electric field, as a developing bias, across the clearance.
Inventors
- 👤 Nobuhiro Hayashi
- 👤 Kimio Nakahata
- 👤 Hatsuo Tajima
- 👤 Shunji Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:41
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0907
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
105 words
A developing apparatus for developing a latent image formed on a latent image bearing member, comprising: a developer carrying member having a surface for carrying thereon a layer of developer, said developer carrying member being exposed, at a developing position, to the latent image bearing member with a clearance therebetween; and means for applying a developing bias to apply an alternating electric field across the clearance, wherein said developing bias applying means applies the alternating electric field across the clearance during a first period of the developing operation and does not apply the alternating electric field thereacross during a second period of the developing operation.
Claim 2
Dependent Claim
105 words
A developing apparatus for developing a latent image formed on a latent image bearing member, comprising: a developer carrying member having a surface for carrying thereon a layer of developer, said developer carrying member being exposed, at a developing position, to the latent image bearing member with a clearance therebetween; and means for applying a developing bias to apply an alternating electric field across the clearance, wherein said developing bias applying means applies the alternating electric field across the clearance during a first period of the developing operation and does not apply the alternating electric field thereacross during a second period of the developing operation.
Claim 3
Dependent Claim
18 words
An apparatus according to claim 1, wherein said first period and second period are alternately and periodically repeated.
Claim 4
Dependent Claim
23 words
An apparatus according to claim 2, wherein the ratio between the first period and the second period is from 1:1/2 to 1:10, inclusive.
Claim 5
Dependent Claim
20 words
An apparatus according to claim 2, wherein a frequency of the alternating electric field in constant during the first period.
Claim 6
Dependent Claim
72 words
An apparatus according to claim 1, wherein said developing bias applying means terminates alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the field is defined as a value lower than the central value.
Claim 7
Dependent Claim
29 words
An apparatus according to claim 1, wherein said developing bias applying means applies, as the alternating electric field, a field having an AC voltage superposed with a DC voltage.
Claim 8
Dependent Claim
129 words
A developing apparatus for developing a latent image formed on a latent image bearing member, comprising: a developer carrying member having a surface for carrying thereon a layer of a developer, said developer carrying member being exposed, at a developing position, to the latent image bearing member with a clearance therebetween; and means for applying a developing bias to apply an alternating electric field across the clearance, and for terminating alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the field is defined as a value lower than the central value.
Claim 9
Dependent Claim
129 words
A developing apparatus for developing a latent image formed on a latent image bearing member, comprising: a developer carrying member having a surface for carrying thereon a layer of a developer, said developer carrying member being exposed, at a developing position, to the latent image bearing member with a clearance therebetween; and means for applying a developing bias to apply an alternating electric field across the clearance, and for terminating alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the field is defined as a value lower than the central value.
Claim 10
Independent Claim
111 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; and developing the latent image, during which step an alternating electric field is applied across the clearance, said developing step including a first period during which the alternating electric field is applied across the clearance and a second period during which the alternating electric field is not applied thereacross.
Claim 11
Independent Claim
111 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; and developing the latent image, during which step an alternating electric field is applied across the clearance, said developing step including a first period during which the alternating electric field is applied across the clearance and a second period during which the alternating electric field is not applied thereacross.
Claim 12
Dependent Claim
18 words
A method according to claim 8, wherein said first period and second period are alternately and periodically repeated.
Claim 13
Dependent Claim
20 words
A method according to claim 8, wherein a frequency of the alternating electric field is constant during the first period.
Claim 14
Dependent Claim
39 words
A method according to claim 8, wherein the alternating field is provided by superposing a DC component and an AC component, and wherein during the second period the AC component is not applied, but the DC component is applied.
Claim 15
Dependent Claim
18 words
A method according to claim 11, wherein the DC component is applied throughout the first and second periods.
Claim 16
Dependent Claim
16 words
A method according to claim 8, wherein the second period is longer than the first period.
Claim 17
Dependent Claim
23 words
A method according to claim 8, wherein the ratio between the first period and the second period is from 1:1/2 to 1:10, inclusive.
Claim 18
Independent Claim
109 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; and developing the latent image, during which an alternating electric field is applied across the clearance, said developing step including a first period during which the alternating electric field is applied across the clearance and a second period during which a different electric field is applied thereacross.
Claim 19
Independent Claim
109 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; and developing the latent image, during which an alternating electric field is applied across the clearance, said developing step including a first period during which the alternating electric field is applied across the clearance and a second period during which a different electric field is applied thereacross.
Claim 20
Independent Claim
159 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; developing the latent image, during which an alternating electric field is applied across the clearance, wherein the latent image is developed with the developer electrically charged to a polarity opposite to that of the latent image; and terminating alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the field is defined as a value lower than the central value.
Claim 21
Independent Claim
159 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; developing the latent image, during which an alternating electric field is applied across the clearance, wherein the latent image is developed with the developer electrically charged to a polarity opposite to that of the latent image; and terminating alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the field is defined as a value lower than the central value.
Claim 22
Independent Claim
191 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; developing the latent image, during which an alternating electric field is applied across the clearance, said developing step including a first period during which the alternating electric field is applied across the clearance and a second period during which the alternating field is not applied thereacross, wherein the latent image is developed with the developer electrically charged to a polarity opposite to that of the latent image; and terminating alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the alternating field is defined as a value lower than the central value.
Claim 23
Independent Claim
191 words
A method of development comprising the steps of: forming a thin layer of developer on a surface of a developer carrying member; exposing the surface of the developer carrying member to a latent image bearing member bearing a latent image to be developed with a clearance therebetween which is larger than the thickness of the thin developer layer at a developing position; developing the latent image, during which an alternating electric field is applied across the clearance, said developing step including a first period during which the alternating electric field is applied across the clearance and a second period during which the alternating field is not applied thereacross, wherein the latent image is developed with the developer electrically charged to a polarity opposite to that of the latent image; and terminating alternating field application at a time when the field has a polarity opposite to that of the developer, wherein positiveness of the polarity of the alternating field is defined as a value higher than a central value of the alternating field, and negativeness of the polarity of the alternating field is defined as a value lower than the central value.
Claim 24
Dependent Claim
23 words
A method according to claim 17, wherein the ratio between the first period and the second period is from 1:1/2 to 1:10, inclusive.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-08 | 1990-03-10 | 1990-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-08 | 1994-03-10 | 1994-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-08 | 1998-03-10 | 1998-09-09 | $7700.00 | Window Closed / Lapsed |