Patent US3677640A successfully refreshed from Google Patents.
US3677640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic contact printing device for use in a photographic contact printer
Assignee: Minolta Co Ltd
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Filing: 1971-04-09
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Granted: 1972-07-18
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Expires: 1991-04-09
Abstract
Abstract In a photographic contact printer, an electrostatic contact printing device comprises an electrode assembly consisting of several pairs of juxtaposed electrodes, each pair of electrodes being oppositely disposed so that an original sheet and a photosensitive sheet which have been superposed pass between. A high electric voltage is applied to the electrodes to create an electrostatic suction force therebetween, and an illuminating light source is located outwardly from the electrodes disposed on the original sheet side, whereby a high electric voltage is applied thereto simultaneously with the printing so that the original sheet and photosensitive sheet are electrostatically enforced to come into close contact with each other. A modification of the structure includes an additional set of electrodes which establish a pre-charge on the superposed original and photosensitive sheet of opposite polarity to the electrostatic charge of the adjoining electrodes.
Inventors
- 👤 Keiji Nakatani
- 👤 Kaoru Takebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:19
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/02; G03B27/14; G03B27/18
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
180 words
In a photographic contact printer, an electrostatic contact printing device comprising: feed rollers for superposing an original sheet and a photosensitive sheet and feeding the superposed sheets into the printing device; and delivery rollers spaced from said feed rollers for delivering said superposed original and photosensitive sheets from the printing device; a belt bridged between said rollers for transferring said superposed original and said photosensitive sheets from said feed rollers to said delivery rollers; an electrode assembly between said rollers comprising plural sets of electrodes oppositely spaced from each other and confronting said superposed original and said photosensitive sheets within a printing space formed between said fEed rollers and said delivery rollers as said sheets pass through said printing device; means for applying a high electric voltage of opposite polarities respectively to each set of electrodes of said electrode assembly to produce an electrostatic suction force for holding said superposed original and photosensitive sheets in contacting relationship; and an illuminating light source located outwardly of the set of electrodes positioned on the original sheet side for exposing said photosensitive sheet.
Claim 2
Dependent Claim
180 words
In a photographic contact printer, an electrostatic contact printing device comprising: feed rollers for superposing an original sheet and a photosensitive sheet and feeding the superposed sheets into the printing device; and delivery rollers spaced from said feed rollers for delivering said superposed original and photosensitive sheets from the printing device; a belt bridged between said rollers for transferring said superposed original and said photosensitive sheets from said feed rollers to said delivery rollers; an electrode assembly between said rollers comprising plural sets of electrodes oppositely spaced from each other and confronting said superposed original and said photosensitive sheets within a printing space formed between said fEed rollers and said delivery rollers as said sheets pass through said printing device; means for applying a high electric voltage of opposite polarities respectively to each set of electrodes of said electrode assembly to produce an electrostatic suction force for holding said superposed original and photosensitive sheets in contacting relationship; and an illuminating light source located outwardly of the set of electrodes positioned on the original sheet side for exposing said photosensitive sheet.
Claim 3
Dependent Claim
64 words
The photographic contact printer as set forth in claim 1, wherein said electrodes comprise conductive wires connected to said means for applying a high electric voltage, and said electrode assembly further comprising shielding plates for supporting said wires in parallel relationship with respect to the superposed original and photosensitive sheets and in perpendicularly crossed relationship relative to the direction of transfer of said sheets.
Claim 4
Dependent Claim
100 words
The photographic contact printer as set forth in claim 1, wherein each set of said electrode assembly confronts each other and comprises a first subset of electrodes and a second subset of electrodes abutting each other and juxtaposed in the transfer direction of the superposed original sheet and the photosensitive sheet; means for applying a high voltage of opposite polarity between electrodes of said first subset in order to create an electrostatic suction force and for applying a high voltage having a reverse polarity from said first subset between electrodes of said second subset for neutralizing said electrostatic suction force.
Claim 5
Dependent Claim
104 words
The photographic contact printer as in claim 3, wherein said electrode assembly comprises a third electrode subset and forming a charging electrode subset, said first subset and said second subset are juxtaposed in the advancing direction of the superposed original sheet and the photosensitive sheet, and wherein said means for applying a high voltage also provides a high voltage having a polarity reverse to the polarity applied to said first subset between respective electrodes of said charging subset for increasing said electrostatic suction force and the reverse polarity applied to said second subset with respect to said first subset neutralizes said electrostatic suction force.
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |