US4133610A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optimum preclean corona current for eliminating the accumulation of contaminants from developers
Assignee: International Business Machines Corp
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Filing: 1977-12-30
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Granted: 1979-01-09
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Expires: 1997-12-30
Abstract
Abstract An electrophotographic machine of the transfer type in which tetrafluoroethylene-coated carrier beads transport toner particles to a development zone by virute of the triboelectric attraction between positive toner and negative tetrafluoroethylene. At the development zone, the carrier beads are crushed together and occasionally a piece of tetrafluoroethylene is worn off of the surface of the beads and carried along on the surface of the photoconductor. These tetrafluoroethylene-wear products are subjected to high level preclean corona current to reverse the triboelectric negative polarity thereof. In that manner, a positive wear product is made to act as though it was toner and is therefore carried out of the machine on copy paper. In a similar manner, paper dust and other contaminants on the photoconductor surface are subjected to a high level preclean corona current to receive a positive charge for being carried out of the machine on the copy paper.
Inventors
- 👤 William J. Bernardelli
- 👤 Allison H. Caudill
- 👤 John A. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:50
CPC Classifications
G; G03; G03G; G03G21/00; G03G21/0005; G03G15/00; G03G15/14; G03G15/16; G03G15/163; G03G15/1635; G03G15/1645; G03G2221/00; G03G2221/0005
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
183 words
An electrophotographic machine of the transfer type including various process stations comprising: a photoconductor; means for moving said photoconductor past process stations in said machine; means for charging said photoconductor at a charging station; means for producing a latent image on said photoconductor at an imaging station; means for developing said latent image at a developing station through the application of toner to said latent image; transfer corona generator means for transferring toner from said photoconductor to a receiving medium at a transfer station; preclean corona generator means for generating charge at a preclean station opposite in polarity to that generated by said charging means; a source of tetrafluoroethylene-wear products through which said wear products come to reside on the surface of said photoconductor; means for adjusting the current of said transfer corona to a level at which the transfer of toner is complete enough to produce quality copy; and means for adjusting the current of said preclean corona to a level which is high enough to prevent tetrafluoroethylene filming of said photoconductor and low enough to prevent toner filming of said photoconductor.
Claim 2
Dependent Claim
183 words
An electrophotographic machine of the transfer type including various process stations comprising: a photoconductor; means for moving said photoconductor past process stations in said machine; means for charging said photoconductor at a charging station; means for producing a latent image on said photoconductor at an imaging station; means for developing said latent image at a developing station through the application of toner to said latent image; transfer corona generator means for transferring toner from said photoconductor to a receiving medium at a transfer station; preclean corona generator means for generating charge at a preclean station opposite in polarity to that generated by said charging means; a source of tetrafluoroethylene-wear products through which said wear products come to reside on the surface of said photoconductor; means for adjusting the current of said transfer corona to a level at which the transfer of toner is complete enough to produce quality copy; and means for adjusting the current of said preclean corona to a level which is high enough to prevent tetrafluoroethylene filming of said photoconductor and low enough to prevent toner filming of said photoconductor.
Claim 3
Dependent Claim
31 words
The machine of claim 1 wherein the preclean corona current is adjusted to a level sufficient to reverse the polarity of the triboelectric charge on the tetrafluoroethylene-wear products and other contaminants.
Claim 4
Dependent Claim
45 words
The machine of claim 2 wherein the preclean corona current is adjusted to an optimum level which is balanced with the level of the transfer corona current so as to produce a charge density equal to transfer corona charge density ± 0.025 μC/cm 2 .
Claim 5
Dependent Claim
126 words
In an electrophotographic machine of the transfer type, including a photoconductor, means for producing a latent image thereon, a developer containing tetrafluoroethylene-coated carrier beads and toner, a transfer corona generator, and a preclean corona generator, wherein said coated carrier beads are used to carry toner particles to a development zone in order to develop a latent image on the machine photoconductor, a method of controlling tetrafluoroethylene-wear products in said machine including the steps of: (1) adjusting the transfer corona charge density to a level between 0.1 μC/cm 2 and 0.3 μC/cm 2 ; and (2) adjusting the preclean current corona level to a value which charges said wear products with a polarity opposite to the normal triboelectric charge without producing significant toner filming of said photoconductor.
Claim 6
Dependent Claim
126 words
In an electrophotographic machine of the transfer type, including a photoconductor, means for producing a latent image thereon, a developer containing tetrafluoroethylene-coated carrier beads and toner, a transfer corona generator, and a preclean corona generator, wherein said coated carrier beads are used to carry toner particles to a development zone in order to develop a latent image on the machine photoconductor, a method of controlling tetrafluoroethylene-wear products in said machine including the steps of: (1) adjusting the transfer corona charge density to a level between 0.1 μC/cm 2 and 0.3 μC/cm 2 ; and (2) adjusting the preclean current corona level to a value which charges said wear products with a polarity opposite to the normal triboelectric charge without producing significant toner filming of said photoconductor.
Claim 7
Dependent Claim
27 words
The method of claim 4 in which the optimum preclean corona charge density level is equal to the transfer corona charge density level ±0.025 μC/cm 2 .
Claim 8
Dependent Claim
73 words
In an electrophotographic machine including a photoconductor moving sequentially through various process stations including a charging station, an imaging station, a developing station, a transfer station including a transfer corona, and a cleaning station including a preclean corona, the improvement comprising: means for adjusting the charge density produced on the photoconductor by the preclean corona to approximately equal the charge density produced on the photoconductor by the transfer corona ±0.025 μC/cm 2 .
Claim 9
Dependent Claim
73 words
In an electrophotographic machine including a photoconductor moving sequentially through various process stations including a charging station, an imaging station, a developing station, a transfer station including a transfer corona, and a cleaning station including a preclean corona, the improvement comprising: means for adjusting the charge density produced on the photoconductor by the preclean corona to approximately equal the charge density produced on the photoconductor by the transfer corona ±0.025 μC/cm 2 .
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) | 1982-01-08 | 1982-07-10 | 1983-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-08 | 1986-07-10 | 1987-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-08 | 1990-07-10 | 1991-01-09 | $7700.00 | Window Closed / Lapsed |