US3977010A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual sensor for multi-nozzle ink jet
Assignee: International Business Machines Corp
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Filing: 1975-12-22
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Granted: 1976-08-24
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Expires: 1995-12-22
Abstract
Abstract A dual antenna structure for inductive sensing of charged ink jet drops. The structure includes two sense rails or wires, each on an opposite side of a series of ink jet drop streams and perpendicular to the streams. Conductive shields are located on the fore and aft sides of each sense rail to shield the rail from all but a small portion of each drop stream path. A separate low impedance amplifier is connected to each sense rail and both are grounded in common to the shields. Using the sensor, various measurements may be made on a jet stream whose drops are charged, including jet alignment, drop arrival time for establishing velocity, charge electrode operation, and charge phasing.
Inventors
- 👤 Byron Ted Erickson
- 👤 Howard Thorndike Hilton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:02
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/07; B41J2/125
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
151 words
In an electrostatic, pressurized ink jet system having a plurality of nozzles arranged in a row and projecting generally parallel ink streams in a predetermined direction, each of which breaks up into a stream of drops continuing in said direction, and having charge means for selectively applying an electrical charge to individual drops upon breakoff from each said stream, the improvement comprising: two elongate electrically conductive sensing means disposed respectively on opposite sides of said drop streams, generally parallel to said row, and perpendicular to said streams; electrically conductive shielding means disposed at least fore and aft of each said sensing means with respect to said direction of said drop streams, and closely spaced from and parallel to said sensing means; and separate low impedance current amplification means connected to each said sensing means and grounded in common to said shielding means for amplifying current signals of said respective sensing means.
Claim 2
Dependent Claim
151 words
In an electrostatic, pressurized ink jet system having a plurality of nozzles arranged in a row and projecting generally parallel ink streams in a predetermined direction, each of which breaks up into a stream of drops continuing in said direction, and having charge means for selectively applying an electrical charge to individual drops upon breakoff from each said stream, the improvement comprising: two elongate electrically conductive sensing means disposed respectively on opposite sides of said drop streams, generally parallel to said row, and perpendicular to said streams; electrically conductive shielding means disposed at least fore and aft of each said sensing means with respect to said direction of said drop streams, and closely spaced from and parallel to said sensing means; and separate low impedance current amplification means connected to each said sensing means and grounded in common to said shielding means for amplifying current signals of said respective sensing means.
Claim 3
Dependent Claim
67 words
The apparatus of claim 1 wherein: said sensing means each responds to the passage of charged drops therebetween by inducing a current flow to said low impedance current amplification means, and said apparatus additionally includes summing means connected to said amplification means for summing said respective current signals to generate a sum signal to indicate thereby the arrival time of said charged drops at said sensing means.
Claim 4
Dependent Claim
71 words
The apparatus of claim 1 wherein: said sensing means each responds to the passage of charged drops therebetween by inducing a current flow to said low impedance current amplification means, and said apparatus additionally includes difference means connected to said amplification means for subtracting said respective current signals to generate a difference signal to indicate thereby any misalignment of said charged drops with respect to a midpoint between said sensing means.
Claim 5
Dependent Claim
27 words
The apparatus of claim 1 wherein said two sensing means additionally each comprises sense rails of uniform cross section along the length thereof adjacent said drop streams.
Claim 6
Dependent Claim
74 words
The apparatus of claim 4: additionally including two laminar dielectric plates having openings therethrough for passage of said ink drop streams; and wherein: said sense rails additionally comprise laminar conductive plates on a plane disposed between said two dielectric plates on opposite sides of said openings; and said shielding means additionally comprise laminar conductive plates disposed on the two surfaces of said dielectric plates opposite said plane and on opposite sides of said openings.
Claim 7
Dependent Claim
77 words
The apparatus of claim 4 wherein: said shielding means additionally comprises a single electrically conductive tubular member having openings there-through laterally with respect to the axis thereof for passage of said ink drop streams; and said sense rails additionally are disposed within said tubular member on opposite sides of said openings; and additionally including a dielectric disposed within said tubular member for supporting and positioning said sense rails and insulating said sense rails from said tubular member.
References Cited (Backward Citations)
US3852768A
Cited
US3886564A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |