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US4376813A
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Reversal development method of electrostatic latent image by the use of high-resistivity magnetic toner
Assignee: Minolta Co Ltd
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Filing: 1982-01-20
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Granted: 1983-03-15
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Expires: 2002-01-20
Abstract
Abstract An improved reversal development method of visualizing an electrostatic latent image through reversal development, including the steps of: forming a magnetic brush around an outer circumferential surface of a developing sleeve by the use of a developer composed of high-resistivity toner having a resistance value of 10 13 Ωcm or more under an electric field of 10 4 V/cm and a charge amount of 5 to 15 μQ/g per unit mass generated by gaseous discharge; and applying simultaneously an a.c. bias, and a d.c. bias approximately equal to a sum of a potential of an image portion of the electrostatic latent image and a potential of its non-image portion to the magnetic brush.
Inventors
- 👤 Shizuo Yuge
- 👤 Toshio Yamamoto
- 👤 Susumu Sakakibara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:50
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0907
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
A reversal development method of visualizing an electrostatic latent image through development, comprising the steps of: forming a magnetic brush around an outer circumferential surface of a developing sleeve accommodating a magnet therein, by the use of a developer composed of high-resistivity magnetic toner having a resistance value of 10 13 Ωcm or more under an electric field of 10 4 V/cm and a charge amount of 5 to 15 μQ/g per unit mass generated by gaseous discharge; rubbing a surface of an electrostatic latent image carrier bearing said electrostatic latent image with said magnetic brush; and applying simultaneously to said magnetic brush during said rubbing, an a.c. bias, and a d.c. bias approximately equal to a sum of a potential of an image portion of said electrostatic latent image and a potential of a non-image portion thereof.
Claim 2
Dependent Claim
138 words
A reversal development method of visualizing an electrostatic latent image through development, comprising the steps of: forming a magnetic brush around an outer circumferential surface of a developing sleeve accommodating a magnet therein, by the use of a developer composed of high-resistivity magnetic toner having a resistance value of 10 13 Ωcm or more under an electric field of 10 4 V/cm and a charge amount of 5 to 15 μQ/g per unit mass generated by gaseous discharge; rubbing a surface of an electrostatic latent image carrier bearing said electrostatic latent image with said magnetic brush; and applying simultaneously to said magnetic brush during said rubbing, an a.c. bias, and a d.c. bias approximately equal to a sum of a potential of an image portion of said electrostatic latent image and a potential of a non-image portion thereof.
Claim 3
Dependent Claim
36 words
A reversal development method as claimed in claim 1, wherein said a.c. bias has a sufficient potential required for charging said high-resistivity magnetic toner forming said magnetic brush to positive and negative polarities through gaseous discharge.
Claim 4
Dependent Claim
59 words
A reversal development method as claimed in claim 2, wherein said high-resistivity magnetic toner having electric charge of the same polarity as that of electric charge held by said electrostatic latent image is electrostatically attracted to said image portion of said electrostatic latent image when said surface of said electrostatic latent image carrier is rubbed with said magnetic brush.
Claim 5
Dependent Claim
28 words
A reversal development method as claimed in claim 3, wherein said a.c. bias is applied to said magnetic brush through said developing sleeve or a bristle-height regulating member.
Claim 6
Dependent Claim
23 words
A reversal development method as claimed in claim 4, wherein said d.c. bias is applied to said magnetic brush through said developing sleeve.
Claim 7
Dependent Claim
28 words
A reversal development method as claimed in claim 4, wherein said developing sleeve is electrically conductive and is provided with an insulating coating on its outer circumferential surface.
References Cited (Backward Citations)
US4288515A
Cited
US4166691A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |