US4174170A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conductive toner transfer photocopying machine
Assignee: Minolta Co Ltd
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Filing: 1977-12-15
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Granted: 1979-11-13
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Expires: 1997-12-15
Abstract
Abstract Photocopying machine comprising shield elements which are provided between an electrophotosensitive medium and a corona discharge unit at a transfer station, define a slit to permit transfer of conductive toner particles onto copy paper charged by the corona discharge unit but prevent imposition on the paper of a charge liable to cause early transfer of toner particles or of a charge liable to cause cancellation of the charge of the toner particles, and hence detachment, of toner particles on the copy paper.
Inventors
- 👤 Toshio Yamamoto
- 👤 Shizuo Yuge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:58
CPC Classifications
H; H01; H01T; H01T19/00; G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/163; G03G15/1635
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
197 words
In a photocopying apparatus wherein a latent image of an original document to be copied is formed on an electrophotosensitive medium, electrically conductive toner particles are applied to said medium to develop said image, and said developed image is transferred onto copy paper by bringing said copy paper into effective contact with said electrophotosensitive medium and applying an ionic current from a corona discharge unit to the rear surface of said copy paper to cause said toner particles to move onto said copy paper, the improvement comprising shield elements which are provided between said electrophotosensitive medium and said discharge unit, and defining a slit for passing the corona discharge and having a width and said corona discharge unit being spaced from said electrophotosensitive medium and the speed of movement of the copy paper past the corona charger and the voltage applied to the corona charger being such that the amount of said current applied to said copy paper is sufficient to cause transfer of toner particles onto said copy paper but insufficient to permit storage in said copy paper of a charge great enough to cancel the charge of said toner particles transferred onto said copy paper.
Claim 2
Dependent Claim
197 words
In a photocopying apparatus wherein a latent image of an original document to be copied is formed on an electrophotosensitive medium, electrically conductive toner particles are applied to said medium to develop said image, and said developed image is transferred onto copy paper by bringing said copy paper into effective contact with said electrophotosensitive medium and applying an ionic current from a corona discharge unit to the rear surface of said copy paper to cause said toner particles to move onto said copy paper, the improvement comprising shield elements which are provided between said electrophotosensitive medium and said discharge unit, and defining a slit for passing the corona discharge and having a width and said corona discharge unit being spaced from said electrophotosensitive medium and the speed of movement of the copy paper past the corona charger and the voltage applied to the corona charger being such that the amount of said current applied to said copy paper is sufficient to cause transfer of toner particles onto said copy paper but insufficient to permit storage in said copy paper of a charge great enough to cancel the charge of said toner particles transferred onto said copy paper.
Claim 3
Dependent Claim
23 words
The improvement as claimed in claim 1, wherein the width of said slit is in the range of from 3 to 5 millimeters.
Claim 4
Dependent Claim
16 words
The improvement as claimed in claim 1, wherein said shield elements are made of dielectric material.
Claim 5
Dependent Claim
40 words
The improvement as claimed in claim 1, wherein said toner employed is a conductive toner having a resistivity in the range of from 10 3 to 10 7 Ωcm when subjected to a compressive pressure of 100 kg/cm 3 .
Claim 6
Dependent Claim
230 words
In photocopying apparatus wherein a latent image of an original document to be copied is formed on a electrophotosensitive medium, electrically conductive toner particles having a resistivity in the range of from 10 3 to 10 7 Ωcm when subjected to a compressive pressure of 100 kg/cm 2 are applied on said medium to develop said image, and said developed image is transferred onto copy paper by bringing said copy paper into effective contact with said electrophotosensitive medium and applying an ionic current from a corona discharge unit to the rear surface of said copy paper to cause said toner particles to move onto said copy paper, the improvement comprising shield elements which are provided between said electrophotosensitive medium and said discharge unit, and defining a slit for passing the corona discharge and having a width of 3 to 5 millimeters, and said corona discharge unit being spaced from said electrophotosensitive medium and the speed of movement of the copy paper past the corona discharge unit being such that when a voltage of more than 8 kV is applied to said corona discharge unit the current applied to the copy paper is sufficient to cause transfer of toner particles onto said copy paper but insufficient to permit storage in said copy paper of a charge great enough to cancel the charge of said toner particles transferred onto said copy paper.
Claim 7
Dependent Claim
230 words
In photocopying apparatus wherein a latent image of an original document to be copied is formed on a electrophotosensitive medium, electrically conductive toner particles having a resistivity in the range of from 10 3 to 10 7 Ωcm when subjected to a compressive pressure of 100 kg/cm 2 are applied on said medium to develop said image, and said developed image is transferred onto copy paper by bringing said copy paper into effective contact with said electrophotosensitive medium and applying an ionic current from a corona discharge unit to the rear surface of said copy paper to cause said toner particles to move onto said copy paper, the improvement comprising shield elements which are provided between said electrophotosensitive medium and said discharge unit, and defining a slit for passing the corona discharge and having a width of 3 to 5 millimeters, and said corona discharge unit being spaced from said electrophotosensitive medium and the speed of movement of the copy paper past the corona discharge unit being such that when a voltage of more than 8 kV is applied to said corona discharge unit the current applied to the copy paper is sufficient to cause transfer of toner particles onto said copy paper but insufficient to permit storage in said copy paper of a charge great enough to cancel the charge of said toner particles transferred onto said copy paper.
Claim 8
Dependent Claim
16 words
Photocopying apparatus as claimed in claim 5, wherein said shield elements are made of dielectric material.
Claim 9
Dependent Claim
239 words
In a photocopying apparatus wherein a latent image of an original document to be copied is formed on an electrophotosensitive medium, electrically conductive toner particles having a resistivity in the range of from 10 3 to 10 7 Ωcm when subjected to a compressive pressure of 100 kg/cm 2 are applied on said medium to develop said image, and said developed image is transferred onto copy paper by bringing said copy paper into effective contact with said electrophotosensitive medium and applying an ionic current from a corona discharge unit having a corona wire to the rear surface of said copy paper to cause said toner particles to move onto said copy paper the improvement comprising shield elements which are provided between said electrophotosensitive medium and said discharge unit, and defining a slit for passing the corona discharge and having a width of 3 to 5 millimeters, and the corona wire is spaced 8 millimeters from said electrophotosensitive medium, and the speed of movement of the copy paper past the corona discharge unit being such that when a voltage of approximately 6 kV is applied to the corona wire of said corona discharge unit, the current applied to the copy paper is sufficient to cause transfer of toner particles onto said copy paper but insufficient to permit storage in said copy paper of a charge great enough to cancel the charge of said toner particles transferred onto said copy paper.
Claim 10
Dependent Claim
239 words
In a photocopying apparatus wherein a latent image of an original document to be copied is formed on an electrophotosensitive medium, electrically conductive toner particles having a resistivity in the range of from 10 3 to 10 7 Ωcm when subjected to a compressive pressure of 100 kg/cm 2 are applied on said medium to develop said image, and said developed image is transferred onto copy paper by bringing said copy paper into effective contact with said electrophotosensitive medium and applying an ionic current from a corona discharge unit having a corona wire to the rear surface of said copy paper to cause said toner particles to move onto said copy paper the improvement comprising shield elements which are provided between said electrophotosensitive medium and said discharge unit, and defining a slit for passing the corona discharge and having a width of 3 to 5 millimeters, and the corona wire is spaced 8 millimeters from said electrophotosensitive medium, and the speed of movement of the copy paper past the corona discharge unit being such that when a voltage of approximately 6 kV is applied to the corona wire of said corona discharge unit, the current applied to the copy paper is sufficient to cause transfer of toner particles onto said copy paper but insufficient to permit storage in said copy paper of a charge great enough to cancel the charge of said toner particles transferred onto said copy paper.
Claim 11
Dependent Claim
16 words
Photocopying apparatus as claimed in claim 7, wherein said shield elements are made of dielectric material.
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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) | 1982-11-12 | 1983-05-14 | 1983-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-12 | 1987-05-14 | 1987-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-12 | 1991-05-14 | 1991-11-13 | $7700.00 | Window Closed / Lapsed |