US5729802A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contact charger for charging a photosensitive member
Assignee: Canon Inc
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Filing: 1996-09-09
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Granted: 1998-03-17
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Expires: 2016-09-09
Abstract
Abstract An image forming apparatus includes an image bearing device, a charger contactable to the image bearing device for effecting contact charging of the image bearing device, the charger being supplied with a voltage having a DC component and an AC component, and the charger being provided with an electrode for receiving the voltage; wherein the following is satisfied: when an electric field formed between the image bearing device and the electrode is not more than |E/d SD | (V/m), a resistance of the charger per unit area of contact between the image bearing device and the charger is larger than 20E/(wCV.sub.DC) (Ωm.sup.2) and is larger than the resistance when the electric field is more than |(E+V DC )/d SD | (V/m) where E(V) is an amplitude of the AC component; w(rad) is an angular velocity of the AC component; d SD (m) is a minimum distance between the electrode and the image bearing device; C(F/m 2 ) is an electrostatic capacity per unit area of the image bearing device; and V DC (V) is a voltage of the DC component.
Inventors
- 👤 Jun Hirabayashi
- 👤 Nobuyuki Ito
- 👤 Harumi Ishiyama
- 👤 Tadashi Furuya
- 👤 Yasunori Chigono
- 👤 Seiji Mashimo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:20
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0241; G03G2215/00; G03G2215/02; G03G2215/021; G03G2215/022
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
189 words
An image forming apparatus comprising: an image bearing member; a charging member contactable to said image bearing member for effecting contact charging of said image bearing member, said charging member being supplied with a voltage having a DC component and an AC component, and said charging member being provided with an electrode for receiving the voltage; wherein the following is satisfied: when an electric field formed between said image bearing member and said electrode is not more than |E/d SD |(V/m), a resistance of said charging member per unit area of contact between said image bearing member and said charging member is larger than 20E/(wCV.sub.DC)(Ωm.sup.2) and is larger than the resistance when the electric field is more than |E/d SD |(V/m), and not more than |(E+V DC )/d SD |(V/m) where E(V) is an amplitude of the AC component; w(rad) is an angular velocity of the AC component; d SD (m) is a minimum distance between said electrode and said image bearing member; C(F/m 2 ) is an electrostatic capacity per unit area of said image bearing member; and V DC (V) is a voltage of the DC component.
Claim 2
Dependent Claim
189 words
An image forming apparatus comprising: an image bearing member; a charging member contactable to said image bearing member for effecting contact charging of said image bearing member, said charging member being supplied with a voltage having a DC component and an AC component, and said charging member being provided with an electrode for receiving the voltage; wherein the following is satisfied: when an electric field formed between said image bearing member and said electrode is not more than |E/d SD |(V/m), a resistance of said charging member per unit area of contact between said image bearing member and said charging member is larger than 20E/(wCV.sub.DC)(Ωm.sup.2) and is larger than the resistance when the electric field is more than |E/d SD |(V/m), and not more than |(E+V DC )/d SD |(V/m) where E(V) is an amplitude of the AC component; w(rad) is an angular velocity of the AC component; d SD (m) is a minimum distance between said electrode and said image bearing member; C(F/m 2 ) is an electrostatic capacity per unit area of said image bearing member; and V DC (V) is a voltage of the DC component.
Claim 3
Dependent Claim
44 words
An apparatus according to claim 1, wherein when the electric field is more than |E/d SD |(V/m), and not more than |(E+V DC )/d SD |(V/m), then the resistance of said charging member per unit contact area is larger than 1 (Ωm 2 ).
Claim 4
Dependent Claim
51 words
An apparatus according to claim 1, wherein when the electric field is more than |E/d SD |(V/m), and not more than |(E+V DC )/d SD |(V/m), then the resistance of a surface layer of said image bearing member is smaller than that when it is not more than |E/d SD |(V/m).
Claim 5
Dependent Claim
21 words
An apparatus according to claim 1, wherein said charging member has an electroconductive particle layer contactable to said image bearing member.
Claim 6
Dependent Claim
22 words
An apparatus according to claim 4, wherein said charging member includes a magnet, and said electroconductive particle layer is of magnetic particles.
Claim 7
Dependent Claim
24 words
An apparatus according to claim 1, wherein said charging member and said image bearing member moves in opposite directions at a contact portion therebetween.
Claim 8
Dependent Claim
35 words
An apparatus according to claim 1-6, wherein said image bearing member has a charge injection layer at its surface, and said charge injection layer has a volume resistivity of 1×10 9 to 1×10 14 (Ωcm).
Claim 9
Dependent Claim
16 words
An apparatus according to claim 1, wherein said image bearing member comprises an electrophotographic photosensitive member.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-16 | 2001-09-15 | 2002-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-16 | 2005-09-15 | 2006-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-16 | 2009-09-15 | 2010-03-17 | $7700.00 | Window Closed / Lapsed |