US3789422A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ink drop coupling capacitance compensation
Assignee: International Business Machines Corp
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Filing: 1972-09-21
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Granted: 1974-01-29
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Expires: 1992-09-21
Abstract
Abstract A character generator is connected to the charging electrode of an ink jet printer nozzle through a compensating circuit which modulates the charging voltage applied to each individual ink drop in accordance with the charges on one or more preceding drops in order to compensate for the capacitance effect of the preceding drops on said one individual drop.
Inventors
- 👤 J Haskell
- 👤 S Tsao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:45
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/07; B41J2/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
169 words
In an ink jet printer wherein a stream of ink drops is directed from a nozzle toward a recording medium, electrode means adjacent said nozzle and the path of said stream, circuit means connecting video means to said electrode means to apply signals thereto to selectively charge different ones of said ink drops to deflect said ink drops in accordance with predetermined video signals to position selected ones of said drops on said recording medium in a predetermined pattern, and compensation means including storage means connected between said circuit means and said electrode means for detecting the charges on previous drops and modifying the video signal from said circuit means for charging a particular drop in accordance with the equation V(t) Alpha (f(t) + Beta 1f(t- sigma t) + Beta 2f(t-2 sigma )-) where V(t) is the compensated charging voltage function; sigma t is the drop generation period; and Alpha is a scaling or amplitude constant; to minimize the effects of said previous drop charges on said particular drop.
Claim 2
Dependent Claim
169 words
In an ink jet printer wherein a stream of ink drops is directed from a nozzle toward a recording medium, electrode means adjacent said nozzle and the path of said stream, circuit means connecting video means to said electrode means to apply signals thereto to selectively charge different ones of said ink drops to deflect said ink drops in accordance with predetermined video signals to position selected ones of said drops on said recording medium in a predetermined pattern, and compensation means including storage means connected between said circuit means and said electrode means for detecting the charges on previous drops and modifying the video signal from said circuit means for charging a particular drop in accordance with the equation V(t) Alpha (f(t) + Beta 1f(t- sigma t) + Beta 2f(t-2 sigma )-) where V(t) is the compensated charging voltage function; sigma t is the drop generation period; and Alpha is a scaling or amplitude constant; to minimize the effects of said previous drop charges on said particular drop.
Claim 3
Dependent Claim
16 words
The invention as defined in claim 1 characterized by said storage means comprising a delay network.
Claim 4
Dependent Claim
27 words
The invention as defined in claim 1 characterized by said storage means comprising a plurality of delay networks connected to said charging electrode through a summing network.
Claim 5
Dependent Claim
34 words
The invention as defined in claim 3 characterized by said delay networks having different values which are integral multiples and being connected in parallel circuit relation between said circuit means and said charging electrode.
Claim 6
Dependent Claim
26 words
The invention as defined in claim 3 characterized by said delay networks comprising similar elements connected in cascade between said circuit means and said charging electrode.
Claim 7
Dependent Claim
68 words
The invention as defined in claim 1 characterized by said compensation means including a voltage divider having sections proportioned according to the terms of the equation V(t) f(t) + Beta 1f(t- sigma t) + Beta 2f(t-2 sigma t)-connected between said circuit means and groUnd, and gate means controlled in accordance with the charge condition of previous drops connecting different sections of said voltage divider to said charging electrode.
Claim 8
Dependent Claim
41 words
The invention as defined in claim 6 characterized by a shift register connected to respond in accordance with said video signals and connected to said gate means to control said gate means in response to charge condition of said preceding drops.
Claim 9
Dependent Claim
34 words
The invention as defined in claim 7 characterized by said gate means being connected to said charging electrode by a maximum priority gate means which passes only the maximum of a plurality of signals.
Claim 10
Dependent Claim
25 words
The invention as defined in claim 8 characterized by said shift register being advanced in accordance with the frequency of formation of said ink drops.
Claim 11
Dependent Claim
155 words
In an ink jet printer wherein a stream of ink drops is directed from a nozzle toward a recording medium, electrode means adjacent said nozzle and the path of said stream, circuit means connecting video means to said electrode means to apply signals thereto to selectively charge different ones of said ink drops to deflect said ink drops in accordance with predetermined video signals to position selected ones of said drops on said recording medium in a predetermined pattern, and compensation means including a RC network and a sample and hold gate with circuit means for delaying the gating operation thereof connected between said circuit means and said electrode means for detecting the charge on a previous drop and modifying the video signal from said circuit means for charging a particular drop in accordance with the value of said previous drop charge to minimize the effects of said previous drop charge on said particular drop.
Claim 12
Dependent Claim
155 words
In an ink jet printer wherein a stream of ink drops is directed from a nozzle toward a recording medium, electrode means adjacent said nozzle and the path of said stream, circuit means connecting video means to said electrode means to apply signals thereto to selectively charge different ones of said ink drops to deflect said ink drops in accordance with predetermined video signals to position selected ones of said drops on said recording medium in a predetermined pattern, and compensation means including a RC network and a sample and hold gate with circuit means for delaying the gating operation thereof connected between said circuit means and said electrode means for detecting the charge on a previous drop and modifying the video signal from said circuit means for charging a particular drop in accordance with the value of said previous drop charge to minimize the effects of said previous drop charge on said particular drop.
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) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |