US4248951A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of image formation with a screen element and charging means
Assignee: Canon Inc
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Filing: 1979-02-05
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Granted: 1981-02-03
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Expires: 1999-02-05
Abstract
Abstract In a method of image formation, a primary electrostatic latent image is formed on a screen having a number of fine openings, the primary electrostatic latent image is used to modulate a flow of ions to thereby form a secondary electrostatic latent image on a recording medium, the secondary electrostatic latent image is developed by the use of a developer, the developed image is transferred to another recording member, the charging polarity of the residual portion of the developer remaining on the recording medium is controlled so that, at a position whereat the recording medium and the screen come close to each other, the residual developer may be subjected to a force directed toward the recording medium by an electric field present between the recording medium and the screen, and thereafter the recording medium is reused.
Inventors
- 👤 Yujiro Ando
- 👤 Katsunobu Ohara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:15
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/05; G03G15/051; G03G15/052
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
182 words
A method of image formation comprising the steps of forming a primary electrostatic latent image on a photosensitive screen having a number of fine openings, using said primary electrostatic latent image to modulate a flow of ions to form a secondary electrostatic latent image on a repetitively usable recording medium under an electric field provided by a bias potential difference between the screen and the recording medium adjacent to a position at which the screen and the recording medium are close to each other, developing said secondary electrostatic latent image by means of a developer, transferring the developed image to a transfer member, applying a charge of the same polarity as that of the ions used to form the secondary latent image to the residual developer remaining on said recording medium after said image transfer such that said residual developer is subjected to a force directed toward said recording medium under said electric field to thereby prevent said residual developer from adhering to said screen, and thereafter moving said recording medium to a position for the formation of another secondary latent image.
Claim 2
Independent Claim
182 words
A method of image formation comprising the steps of forming a primary electrostatic latent image on a photosensitive screen having a number of fine openings, using said primary electrostatic latent image to modulate a flow of ions to form a secondary electrostatic latent image on a repetitively usable recording medium under an electric field provided by a bias potential difference between the screen and the recording medium adjacent to a position at which the screen and the recording medium are close to each other, developing said secondary electrostatic latent image by means of a developer, transferring the developed image to a transfer member, applying a charge of the same polarity as that of the ions used to form the secondary latent image to the residual developer remaining on said recording medium after said image transfer such that said residual developer is subjected to a force directed toward said recording medium under said electric field to thereby prevent said residual developer from adhering to said screen, and thereafter moving said recording medium to a position for the formation of another secondary latent image.
Claim 3
Dependent Claim
37 words
A method according to claim 1, wherein said step of charging said residual developer remaining on said recording medium after the image transfer comprises uniformly imparting corona discharges of different polarities to said recording medium in succession.
Claim 4
Dependent Claim
29 words
A method according to claim 2, wherein the step of uniformly imparting corona discharges of different polarities is effected by a combination of DC corona dischargers of different polarities.
Claim 5
Dependent Claim
38 words
A method according to claim 2, wherein the step of uniformly imparting corona discharges of different polarities is effected by a combination of a DC corona discharger and an AC corona discharger which is biased with DC corona.
Claim 6
Dependent Claim
81 words
A method according to claim 2, wherein the uniform imparting of corona discharges is performed with a corona discharger having first and second discharge devices, wherein said first corona discharger device imparts corona discharge of a first polarity to said recording medium and said second corona discharger device imparts corona discharge of a second polarity to said recording medium, and after having passed by said second corona discharger device, the surface potential of said recording medium is of the second polarity.
Claim 7
Dependent Claim
84 words
a method according to claim 2, wherein the uniform imparting of corona discharges is performed with a corona discharger having first and second discharge devices, wherein said first corona discharger device imparts corona discharge of a first polarity to said recording medium, wherein said second corona discharger device includes a discharge electrode which applies a voltage of a second polarity to said recording medium and a grid to which is applied a voltage opposite in polarity to the voltage applied to said discharge electrode.
Claim 8
Dependent Claim
27 words
A method according to claim 1, wherein said recording medium is reusable without the provision of cleaning means for removing the residual developer on said recording medium.
Claim 9
Dependent Claim
15 words
A method according to claim 1, wherein said secondary electrostatic latent image is positively developed.
Claim 10
Independent Claim
197 words
A method of image formation comprising the steps of forming a primary electrostatic latent image of a photosensitive screen having a number of fine openings, using said primary electrostatic latent image to modulate a flow of ions to form a secondary electrostatic image on a repetitively usable recording medium under an electric field provided by a bias potential difference between the screen and the recording medium adjacent to a position at which the screen and the recording medium come close to each other, developing said recording medium with a developer in accordance with said secondary electrostatic latent image, transferring the developed image to a transfer member, applying a charge of the same polarity as that of the ions used to form the secondary latent image to the residual developer remaining on said recording medium after transfer such that the residual developer is subjected to a force directed toward said recording medium under said electric field to thereby prevent said residual developer from adhering to said screen, and thereafter reusing said recording medium to form a plurality of additional secondary electrostatic latent images from said primary electrostatic latent image, and developing and transferring said plurality of additional images.
Claim 11
Independent Claim
197 words
A method of image formation comprising the steps of forming a primary electrostatic latent image of a photosensitive screen having a number of fine openings, using said primary electrostatic latent image to modulate a flow of ions to form a secondary electrostatic image on a repetitively usable recording medium under an electric field provided by a bias potential difference between the screen and the recording medium adjacent to a position at which the screen and the recording medium come close to each other, developing said recording medium with a developer in accordance with said secondary electrostatic latent image, transferring the developed image to a transfer member, applying a charge of the same polarity as that of the ions used to form the secondary latent image to the residual developer remaining on said recording medium after transfer such that the residual developer is subjected to a force directed toward said recording medium under said electric field to thereby prevent said residual developer from adhering to said screen, and thereafter reusing said recording medium to form a plurality of additional secondary electrostatic latent images from said primary electrostatic latent image, and developing and transferring said plurality of additional images.
Claim 12
Independent Claim
178 words
A method of image formation comprising the steps of forming a primary electrostatic latent image on a photosenstive screen having a number of fine openings, using said primary electrostatic latent image to modulate a flow of ions to form a secondary electrostatic latent image on a repetitively usable recording medium under an electric field provided by a bias potential difference between the screen and the recording medium adjacent to a position at which the screen and the recording medium come close to each other, reverse-developing said secondary electrostatic latent image with a developer, transferring the developed image to a transfer member, applying a charge of the same polarity as that of the ions used to form the secondary latent image to the residual developer remaining on said recording medium after transfer such that the residual developer is subjected to a force directed toward said recording medium under said electric field to thereby prevent said residual developer from adhering to said screen, and thereafter moving said recording medium to a position for the formation of another secondary latent image.
Claim 13
Independent Claim
178 words
A method of image formation comprising the steps of forming a primary electrostatic latent image on a photosenstive screen having a number of fine openings, using said primary electrostatic latent image to modulate a flow of ions to form a secondary electrostatic latent image on a repetitively usable recording medium under an electric field provided by a bias potential difference between the screen and the recording medium adjacent to a position at which the screen and the recording medium come close to each other, reverse-developing said secondary electrostatic latent image with a developer, transferring the developed image to a transfer member, applying a charge of the same polarity as that of the ions used to form the secondary latent image to the residual developer remaining on said recording medium after transfer such that the residual developer is subjected to a force directed toward said recording medium under said electric field to thereby prevent said residual developer from adhering to said screen, and thereafter moving said recording medium to a position for the formation of another secondary latent image.
Claim 14
Dependent Claim
27 words
A method according to claim 10, wherein said recording medium is reusable without the provision of cleaning means for removing the residual developer on said recording medium.
Claim 15
Independent Claim
113 words
A method of image formation comprising the steps of forming a primary electrostatic latent image on a photosensitive screen having a number of fine openings; using said primary electrostatic latent image to modulate a flow of ions to thereby form a secondary electrostatic latent image on a recording medium, developing said secondary electrostatic latent image with a developer, wherein before modulation of the flow of ions, said recording medium is uniformly charged to a polarity opposite to that of said ions to form a secondary latent image having a first polarity of electric charge at the dark areas of the image and the opposite polarity of electric charge at the light areas thereof.
Claim 16
Independent Claim
113 words
A method of image formation comprising the steps of forming a primary electrostatic latent image on a photosensitive screen having a number of fine openings; using said primary electrostatic latent image to modulate a flow of ions to thereby form a secondary electrostatic latent image on a recording medium, developing said secondary electrostatic latent image with a developer, wherein before modulation of the flow of ions, said recording medium is uniformly charged to a polarity opposite to that of said ions to form a secondary latent image having a first polarity of electric charge at the dark areas of the image and the opposite polarity of electric charge at the light areas thereof.
Claim 17
Dependent Claim
24 words
A method according to claim 12, wherein said recording medium is charged with a corona discharger before the modulation of the flow of ions.
Claim 18
Dependent Claim
15 words
A method according to claim 13, wherein said corona discharger is provided with a grid.
Claim 19
Dependent Claim
27 words
A method according to claim 12, wherein said recording medium is charged with sequential corona discharges of different polarities, before the modulation of the flow of ions.
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) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |