US3866533A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical print impression control
Assignee: International Business Machines Corp
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Filing: 1972-12-26
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Granted: 1975-02-18
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Expires: 1992-12-26
Abstract
Abstract Impression control for an impact printer is provided by changing the width of the pulse applied to the print hammers in accordance with the thickness of the forms on which printing is being performed and in accordance with the voltage of the source energizing the print hammers, so as to maintain a constant impact force to provide uniform print density for different forms thicknesses. Misregistration of characters caused by a variation in the rate of movement of the print hammer is compensated for by changing the start time of the pulse energizing the hammer.
Inventors
- 👤 Richard L Gilbert
- 👤 John G Hamilton
- 👤 Tatsuo Hasegawa
- 👤 Charles O Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:15
CPC Classifications
B; B41; B41J; B41J1/00; B41J1/20; B41J9/00; B41J9/44; B41J9/48
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
249 words
In a control system for a printer having a type carrier bearing a plurality of type characters and movable along a print line past a plurality of print positions for impacting one or more forms having a different thickness to print thereon, a plurality of print hammers aligned with said print positions each having unsaturated electromagnetic actuating means to impart print energy to said hammers, said electromagnetic actuating means being selectively operable in response to electrical pulses applied thereto from a source of electrical energy to actuate said print hammers to impact said forms and type characters, said print energy varying with changes in the voltage of said source and the width of said pulses, circuit means connected to effect selective energization of said print hammer electromagnetic actuating means from said source of electrical energy in accordance with the presence of particular type characters at each of said print positions, and control means including means responsive to at least one of the variable operating conditions comprising variation of the voltage of the source and variation in forms thickness which affect the print hammer impact force connected to said circuit means and to said print hammer electromagnetic actuating means to selectively apply energizing pulses of variable width and hence duration to said print hammer electromagnetic actuating means in accordance with said variable operating conditions to correct for changes in print impact force caused by said variable operating conditions so as to provide a substantially constant print hammer print impact force.
Claim 2
Dependent Claim
249 words
In a control system for a printer having a type carrier bearing a plurality of type characters and movable along a print line past a plurality of print positions for impacting one or more forms having a different thickness to print thereon, a plurality of print hammers aligned with said print positions each having unsaturated electromagnetic actuating means to impart print energy to said hammers, said electromagnetic actuating means being selectively operable in response to electrical pulses applied thereto from a source of electrical energy to actuate said print hammers to impact said forms and type characters, said print energy varying with changes in the voltage of said source and the width of said pulses, circuit means connected to effect selective energization of said print hammer electromagnetic actuating means from said source of electrical energy in accordance with the presence of particular type characters at each of said print positions, and control means including means responsive to at least one of the variable operating conditions comprising variation of the voltage of the source and variation in forms thickness which affect the print hammer impact force connected to said circuit means and to said print hammer electromagnetic actuating means to selectively apply energizing pulses of variable width and hence duration to said print hammer electromagnetic actuating means in accordance with said variable operating conditions to correct for changes in print impact force caused by said variable operating conditions so as to provide a substantially constant print hammer print impact force.
Claim 3
Dependent Claim
41 words
The invention as defined in claim 1 characterized by said control means operating to dynamically vary the width and duration of the energizing pulses of said print hammers and effect a variable delay in the time of initiating said energizing pulses.
Claim 4
Dependent Claim
56 words
The invention as defined in claim 2 characterized by said control means being operable to vary the delay in initiating said energizing pulses of said print hammer in the same sense as a variation in voltage of the source of energization and vary the width and hence duration of the energizing pulses in the opposite sense.
Claim 5
Dependent Claim
60 words
The invention as defined in claim 2 characterized by said control means being operable to reduce the width and hence duration of the energizing pulse of said print hammers with a reduction in the thickness of the forms on which printing is being done and reduce the delay in initiating said energizing pulse to provide a substantially constant impact time.
Claim 6
Dependent Claim
48 words
The invention as defined in claim 1 characterized by said circuit means including a plurality of latches which are selectively set in accordance with the particular print hammers to be fired, and said control means being connected to gate means connected between said latches and said print hammers.
Claim 7
Dependent Claim
100 words
The invention as defined in claim 5 characterized by said control means including a pulse width latch, connected to said gate means and a pulse width generator selectively producing pulse of variable width and hence duration responsive to but in non-linear relation with respect to source voltage and forms thickness connected to said pulse width latch to reset said pulse width latch at different times in a non-linear relation to said source voltage and forms thickness, so as to determine the duration of the energization of said print hammer electromagnetic actuating means by a pulse from said pulse width latch.
Claim 8
Dependent Claim
66 words
The invention as defined in claim 5 characterized by said control means including a fire delay latch connected by gate means to said pulse width latch and controlled by a delay generator which is non-linear with respect to source voltage and a delay generator which is non-linear with respect to forms thickness connected in cascade with said fire delay latch to reset said fire delay latch.
Claim 9
Dependent Claim
66 words
The invention as defined in claim 5 characterized by said circuit means including a subcycle gating ring connected to said control means to effect selective energization of said latches in groups in a predetermined order, and said subcycle gating ring being also connected to said control means in a different order so as to gate said latches on the following subcycle in which they are selected.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |