Patent US267027A successfully refreshed from Google Patents.
Patent US3852768A successfully refreshed from Google Patents.
US3852768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Charge detection for ink jet printers
Assignee: International Business Machines Corp
•
Filing: 1973-08-17
•
Granted: 1974-12-03
•
Expires: 1993-08-17
Abstract
Abstract Circuits are described involving a method of detecting charges on drops in an ink jet stream without contacting the stream. This permits a determination of proper synchronization and charging of the drops, the velocity of the ink stream, the extent of deflection of the drops, and whether or not the stream is in operation, or has stopped.
Inventors
- 👤 R Williams
- 👤 J Carmichael
- 👤 D West
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:24
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/24; B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/07; B41J2/12; G01R5/00; G01R5/28
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
190 words
A sensor system for ink jet printers, particularly providing reduced noise and improved signal to noise ratio, comprising: nozzle means for forming and propelling a stream of ink jet drops, charging means for charging said ink drops, deflecting means for deflecting said ink drops in accordance with the charge on said drops in a predetermined path toward a document to be printed, or the like; sensor means positioned downstream from said nozzle means in the path of travel of said ink drops, said sensor means comprising an assembly of laminar elements including a sensor element, an inner shield, and an outer shield, and said sensor means having an aperture through which said ink drops pass, the arrangement being such that drops passing through said aperture are capacitively coupled to said sensor means for generating charges thereon in timed relation to passage of drops through the aperture of said sensor means; means interconnected with said outer shield for electrically grounding said outer shield to thereby reduce noise pickup by said sensor means; and a circuit interconnected with said sensor element and said inner shield for developing signals representative of detected charges.
Claim 2
Dependent Claim
190 words
A sensor system for ink jet printers, particularly providing reduced noise and improved signal to noise ratio, comprising: nozzle means for forming and propelling a stream of ink jet drops, charging means for charging said ink drops, deflecting means for deflecting said ink drops in accordance with the charge on said drops in a predetermined path toward a document to be printed, or the like; sensor means positioned downstream from said nozzle means in the path of travel of said ink drops, said sensor means comprising an assembly of laminar elements including a sensor element, an inner shield, and an outer shield, and said sensor means having an aperture through which said ink drops pass, the arrangement being such that drops passing through said aperture are capacitively coupled to said sensor means for generating charges thereon in timed relation to passage of drops through the aperture of said sensor means; means interconnected with said outer shield for electrically grounding said outer shield to thereby reduce noise pickup by said sensor means; and a circuit interconnected with said sensor element and said inner shield for developing signals representative of detected charges.
Claim 3
Dependent Claim
40 words
The apparatus of claim 1, wherein said sensor means comprises: a laminated structure composed of alternate layers of copper and Mylar having an aperture formed therein, the copper laminations serving as the sensor element, inner shield, and outer shield elements.
Claim 4
Dependent Claim
59 words
The apparatus of claim 1, wherein said sensor means comprises: a cylindrical structure composed of concentrically mounted elements comprising a central concentric metallic sensor element, an inner shield surrounding said sensor element, an outer shield surrounding said inner shield, insulation interposed between said shields, and an aperture formed through the center of said sensor element in said cylindrical structure.
Claim 5
Dependent Claim
39 words
The apparatus of claim 1, further comprising: a field effect transistor amplifier in said circuit means; and means interconnecting said sensor element and said inner shield element to said amplifier for detection of charges developed in said sensor means.
Claim 6
Dependent Claim
77 words
The apparatus of claim 1, further comprising: means positioning said sensor means relative to said charging means in order that charges originating from said charging means are developed in a balanced fashion on both said inner shield and said outer shield thereby having an equal and opposite effect, and cancelling out charges induced by said charging means in relation to charges induced by said individual ink drops as they pass through the aperture of said sensor means.
Claim 7
Dependent Claim
36 words
The apparatus of claim 1, further comprising: strobe means incorporated in said circuit means for time strobing charges induced in said sensor means in order to further minimize effects of noise induced in said sensor means.
References Cited (Backward Citations)
US3769632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |