US5287146A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contact type charging device having voltage limiter
Assignee: Minolta Co Ltd
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Filing: 1992-06-30
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Granted: 1994-02-15
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Expires: 2012-06-30
Abstract
Abstract A contact type charging device having a contact member for making contact with the surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus of the electrophotographic type, and having a charging device which has a high resistance resistor connected serially to the contact member so as to apply a voltage to the contact member. The contact type charging device has a regulating member for regulating the upper limit of the absolute value of the voltage applied to the contact member to prevent excessive current flow to the contact member, or has a regulating member for regulating the lower limit of the absolute value of the voltage applied to the contact member to prevent a greater than necessary drop of the voltage applied to the charge bearing member.
Inventors
- 👤 Koji Uno
- 👤 Yasuo Tanaka
- 👤 Tateki Oka
- 👤 Hitoshi Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:28
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0216; G03G15/0283; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1675
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
90 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating an upper limit of an absolute value of the voltage applied to said contact member.
Claim 2
Dependent Claim
90 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating an upper limit of an absolute value of the voltage applied to said contact member.
Claim 3
Dependent Claim
26 words
The contact type charging device as claimed in claim 1, wherein the resistance value of said resistor is higher than the resistance of said contact member.
Claim 4
Dependent Claim
33 words
The contact type charging device as claimed in claim 1, wherein said regulating means regulates the upper limit of the absolute value by regulating a lower limit of the voltage of the resistor.
Claim 5
Dependent Claim
27 words
The contact type charging device as claimed in claim 1, wherein said contact member is a charge brush and said charge bearing member is a photosensitive member.
Claim 6
Dependent Claim
23 words
The contact type charging device as claimed in claim 1, wherein said regulating means includes a varistor parallelly connected with said contact member.
Claim 7
Dependent Claim
90 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating a lower limit of an absolute value of the voltage applied to said contact member.
Claim 8
Dependent Claim
90 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating a lower limit of an absolute value of the voltage applied to said contact member.
Claim 9
Dependent Claim
26 words
The contact type charging device as claimed in claim 6, wherein the resistance value of said resistor is higher than the resistance of said contact member.
Claim 10
Dependent Claim
27 words
The contact type charging device as claimed in claim 6, wherein said contact member is a transfer roller and said charge bearing member is a recording medium.
Claim 11
Dependent Claim
22 words
The contact type charging device as claimed in claim 6, wherein said regulating means includes a varistor parallelly connected with said resistor.
Claim 12
Dependent Claim
109 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating a lower limit of the voltage applied to the contact member, the regulating means including impedance which substantially becomes zero when the voltage applied to said contact member becomes lower than a predetermined value.
Claim 13
Dependent Claim
109 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating a lower limit of the voltage applied to the contact member, the regulating means including impedance which substantially becomes zero when the voltage applied to said contact member becomes lower than a predetermined value.
Claim 14
Dependent Claim
28 words
The contact type charging device as claimed in claim 10, wherein said contact member is a transfer roller and said charge bearing member is an image recording medium.
Claim 15
Dependent Claim
134 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating a lower limit of the voltage applied to the contact member, the regulating means including first impedance operated when the voltage applied to said contact member becomes higher than a predetermined value, and second impedance which is lower than said first impedance and is operated when the voltage applied to the contact member becomes lower than the predetermined value.
Claim 16
Dependent Claim
134 words
A contact type charging device which makes contact with a surface of a charge bearing member so as to apply an electric charge to the surface in an image forming apparatus, the contact type charging device comprising: a contact member for making contact with the charge bearing member; a resistor serially connected to the contact member; voltage applying means for applying a voltage to said contact member via said resistor; and regulating means for regulating a lower limit of the voltage applied to the contact member, the regulating means including first impedance operated when the voltage applied to said contact member becomes higher than a predetermined value, and second impedance which is lower than said first impedance and is operated when the voltage applied to the contact member becomes lower than the predetermined value.
Claim 17
Dependent Claim
28 words
The contact type charging device as claimed in claim 12, wherein said contact member is a transfer roller and said charge bearing member is an image recording medium.
Claim 18
Dependent Claim
17 words
The contact type charging device as claimed in claim 8, wherein said recording medium is a paper.
Claim 19
Dependent Claim
17 words
The contact type charging device as claimed in claim 11, wherein said recording medium is a paper.
Claim 20
Dependent Claim
17 words
The contact type charging device as claimed in claim 13, wherein said recording medium is a paper.
References Cited (Backward Citations)
US3879120A
Cited
US3924943A
Cited
JPS5635159A
Cited
US4383752A
Cited
US4466732A
Cited
US4565438A
Cited
US4631470A
Cited
US4977430A
Cited
EP0428172A2
Cited
US5084740A
Cited
EP0476981A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-14 | 1997-08-16 | 1998-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-14 | 2001-08-16 | 2002-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-14 | 2005-08-16 | 2006-02-15 | $7700.00 | Window Closed / Lapsed |