Patent US4575731A successfully refreshed from Google Patents.
US4575731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro resistive printhead drive level sensing and control
Assignee: IBM Information Products Corp
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Filing: 1984-10-30
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Granted: 1986-03-11
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Expires: 2004-10-30
Abstract
Abstract A voltage mode printhead drive for a resistive ribbon 20 employs sensing electrodes 7a contiguous to drive electrodes 1a through 1n. Electrodes 7a sense the return voltage, Vc, from the drive electrodes to ground. Electrodes 7a are mounted in and are a part of the printhead.
Inventors
- 👤 Frank J. Horlander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:44
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/385; B41J2/425; G; G01; G01D; G01D15/00; G01D15/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
67 words
A printhead supporting electrodes including a plurality of printing electrodes for carrying driving current for printing, said printhead having integrally therein at least one sensing electrode for sensing voltage on a ribbon being printed from by said printing electrodes, each said sensing electrode being separated from said printing electrodes and connected to an electrical control circuit for setting the level of drive current to said printing electrodes.
Claim 2
Dependent Claim
67 words
A printhead supporting electrodes including a plurality of printing electrodes for carrying driving current for printing, said printhead having integrally therein at least one sensing electrode for sensing voltage on a ribbon being printed from by said printing electrodes, each said sensing electrode being separated from said printing electrodes and connected to an electrical control circuit for setting the level of drive current to said printing electrodes.
Claim 3
Dependent Claim
48 words
The printhead as in claim 1 in which said electrical control circuit comprises a differential amplifier with said connection being to one input of said differential amplifier, said connection also being connected to a current source to supply a substantial current of magnitude insignificant with respect to printing.
Claim 4
Dependent Claim
63 words
A printhead having in the order of magnitude of forty printing electrodes for carrying driving current for printing and a sensing electrode on each side of said printing electrodes, said printing electrodes and said sensing electrodes being in a column, and a connection to said sensing electrodes for an electrical control circuit for setting the level of drive current to said printing electrodes.
Claim 5
Dependent Claim
63 words
A printhead having in the order of magnitude of forty printing electrodes for carrying driving current for printing and a sensing electrode on each side of said printing electrodes, said printing electrodes and said sensing electrodes being in a column, and a connection to said sensing electrodes for an electrical control circuit for setting the level of drive current to said printing electrodes.
Claim 6
Dependent Claim
48 words
The printhead as in claim 3 in which said electrical control circuit comprises a differential amplifier with said connection being to one input of said differential amplifier, said connection also being connected to a current source to supply a substantial current of magnitude insignificant with respect to printing.
Claim 7
Dependent Claim
84 words
A resistive ribbon printer comprising a printhead having a plurality of printing electrodes for carrying driving current to a resistive ribbon for printing, a sensing electrode mounted within said printhead for sensing voltage by contact with the surface of said resistive ribbon, a differential amplifier, means connecting said sensing electrode to one input of said differential amplifier, and means connecting the output of said differential amplifier in series circuit with said printing electrodes to drive said printing electrodes for printing by said resistive ribbon.
Claim 8
Dependent Claim
84 words
A resistive ribbon printer comprising a printhead having a plurality of printing electrodes for carrying driving current to a resistive ribbon for printing, a sensing electrode mounted within said printhead for sensing voltage by contact with the surface of said resistive ribbon, a differential amplifier, means connecting said sensing electrode to one input of said differential amplifier, and means connecting the output of said differential amplifier in series circuit with said printing electrodes to drive said printing electrodes for printing by said resistive ribbon.
Claim 9
Dependent Claim
32 words
The printer as in claim 1 also comprising a constant current source for providing current of magnitude insignificant with respect to printing and means connecting said current source to said one input.
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) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |