US3769629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multicolor permanent and erasable printing
Assignee: International Business Machines Corp
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Filing: 1972-07-28
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Granted: 1973-10-30
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Expires: 1992-07-28
Abstract
Abstract An electro-chemical printing system operable in either a permanent printing or erasable printing mode. A single electrode may function as both the permanent marking electrode and the erasable marking electrode simply by reversing the polarity of the potential applied to the electrode. Provision is also made for erasing erasable markings. A salt bridge may be provided between a reference electrode and the recording medium to prevent a counter-mark during erasing.
Inventors
- 👤 C Sambucetti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:22
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/20; B41M5/205
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
103 words
An electro-chemical printing system comprising: a recording medium impregnated with a conductive salt, a reducing agent and an electrochromic material, a marking electrode composed of a metal that dissolves releasing ions when a first polarity potential difference is applied between it and a reference electrode for forming a permanent mark on said medium, said marking electrode producing an erasable mark when a second polarity potential difference, opposite said first polarity potential difference, is applied between it and said reference electrode, an erase electrode, a reference electrode, and a reversible polarity potential source coupled between said marking and erase electrodes and said reference electrode.
Claim 2
Dependent Claim
103 words
An electro-chemical printing system comprising: a recording medium impregnated with a conductive salt, a reducing agent and an electrochromic material, a marking electrode composed of a metal that dissolves releasing ions when a first polarity potential difference is applied between it and a reference electrode for forming a permanent mark on said medium, said marking electrode producing an erasable mark when a second polarity potential difference, opposite said first polarity potential difference, is applied between it and said reference electrode, an erase electrode, a reference electrode, and a reversible polarity potential source coupled between said marking and erase electrodes and said reference electrode.
Claim 3
Dependent Claim
25 words
The electro-chemical printing system of claim 1 wherein said marking electrode is composed of silver and said erase and reference electrodes are composed of platinum.
Claim 4
Dependent Claim
15 words
The electro-chemical printing system of claim 2 wherein said electrochromic material is a pH indicator.
Claim 5
Dependent Claim
15 words
The electro-chemical printing system of claim 2 wherein said electrochromic material is a Redox system.
Claim 6
Dependent Claim
27 words
The electro-chemical printing system of claim 2 further including a conductive rotatable electrode holder holding said marking and erase electrodes and being coupled to said potential source.
Claim 7
Dependent Claim
122 words
An electro-chemical printing system comprising; a recording medium formed of a porous material impregnated with potassium fluoride, ascorbic acid and an electrochromic material, a silver mark electrode, for generating permanent or erasable marks on said medium and positioned on a first surface thereof a platinum mark/erase electrode positioned on said first surface a reference electrode positioned on said medium, and a reversible polarity potential source coupled between said reference electrode and said mark and mark/erase electrodes, whereby a permanent mark is produced by said mark electrode when it iS at a positive potential with respect to said reference electrode and an erasable mark is produced by said mark electrode when it is at a negative potential with respect to said reference electrode.
Claim 8
Dependent Claim
122 words
An electro-chemical printing system comprising; a recording medium formed of a porous material impregnated with potassium fluoride, ascorbic acid and an electrochromic material, a silver mark electrode, for generating permanent or erasable marks on said medium and positioned on a first surface thereof a platinum mark/erase electrode positioned on said first surface a reference electrode positioned on said medium, and a reversible polarity potential source coupled between said reference electrode and said mark and mark/erase electrodes, whereby a permanent mark is produced by said mark electrode when it iS at a positive potential with respect to said reference electrode and an erasable mark is produced by said mark electrode when it is at a negative potential with respect to said reference electrode.
Claim 9
Dependent Claim
20 words
The printing system of claim 6 further including a rotatable electrode holder wherein are mounted said mark and mark/erase electrodes.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |