US4024941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dot matrix type serial printer
Assignee: NEC Corp
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Filing: 1975-12-11
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Granted: 1977-05-24
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Expires: 1995-12-11
Abstract
Abstract A step motor is employed as a source of power for transverse feed of the printing head assembly with a combination of a slitted rotary disc secured to the motor output shaft and a stationary detector unit provided to control the motor operation and the dot-printing head operation in precisely timed relation to each other. The rotary disc is also slotted to serve the purpose of defining for the printing head assembly a print starting position spaced a definite distance to the right from its rest position. The printer structure, including a minimum of movable component parts, is capable of forming characters without any lack of "dot" and is minimized in power consumption and noise particularly in idling operation.
Inventors
- 👤 Aisuke Sekikawa
- 👤 Takahiko Aragaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:52
CPC Classifications
B; B41; B41J; B41J19/00; B41J19/18; B41J19/20; B41J19/202; B41J2/00; B41J2/22; B41J2/23; B41J2/235; B41J2/24; Y; Y10; Y10S; Y10S400/00; Y10S400/903
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
253 words
A dot matrix type serial printing device comprising: a movably mounted carriage; a printing head assembly on said carriage, said head including a set of linearly aligned print wires and electromagnetic actuator means for driving the print wires; a step motor having an output shaft and operatively connected with said carriage to impart a transverse feed and a return movement to said carriage; a rotary disc fixedly mounted on the output shaft of said motor and formed with a circularly arcuate slot with opposite end edges therein and a circular row of equally spaced radially aligned slits, said slot and said row being in concentric relation with each other around the axis of said rotary disc, said radial slits being equal in number to that of the operation steps of said step motor in each revolution thereof; stationary detector means including first and second photoelectric sensors arranged with respect to said rotary disc to respectively scan said arcuate slot and said row of slits as said step motor rotates said rotary disc; said detector means generating a signal defining a print starting end position for said printing head assembly by detecting one of the opposite end edges of said arcuate slot in said rotary disc as said end edge is detected by the first of said photoelectric sensors and wherein said printing head assembly and step motor are controlled to operate in timed relation to each other as said radial slits in said rotary disc are successively detected by the second photoelectric sensor.
Claim 2
Dependent Claim
253 words
A dot matrix type serial printing device comprising: a movably mounted carriage; a printing head assembly on said carriage, said head including a set of linearly aligned print wires and electromagnetic actuator means for driving the print wires; a step motor having an output shaft and operatively connected with said carriage to impart a transverse feed and a return movement to said carriage; a rotary disc fixedly mounted on the output shaft of said motor and formed with a circularly arcuate slot with opposite end edges therein and a circular row of equally spaced radially aligned slits, said slot and said row being in concentric relation with each other around the axis of said rotary disc, said radial slits being equal in number to that of the operation steps of said step motor in each revolution thereof; stationary detector means including first and second photoelectric sensors arranged with respect to said rotary disc to respectively scan said arcuate slot and said row of slits as said step motor rotates said rotary disc; said detector means generating a signal defining a print starting end position for said printing head assembly by detecting one of the opposite end edges of said arcuate slot in said rotary disc as said end edge is detected by the first of said photoelectric sensors and wherein said printing head assembly and step motor are controlled to operate in timed relation to each other as said radial slits in said rotary disc are successively detected by the second photoelectric sensor.
Claim 3
Independent Claim
79 words
The apparatus of claom 1, wherein said first sensor detecting said slot generates a first signal when said is passing the first sensor and a second signal when the slot is displaced from the first sensor; said detector means including means coupled to said first and second sensors and responsive to the passage of one end of said slot and the passage of the next slit detected gy said second sensor for enabling actuation of said printing head assembly.
Claim 4
Independent Claim
79 words
The apparatus of claom 1, wherein said first sensor detecting said slot generates a first signal when said is passing the first sensor and a second signal when the slot is displaced from the first sensor; said detector means including means coupled to said first and second sensors and responsive to the passage of one end of said slot and the passage of the next slit detected gy said second sensor for enabling actuation of said printing head assembly.
Claim 5
Dependent Claim
64 words
The apparatus of claim 1, including means responsive to a return signal for driving said motor to return the carriage towards the starting position; meas responsive to said opposite end edge of said slot for maintaining said motor energized to move the head assembly a predetermined distance beyond the first print position to enable the previously printed line to be viewed without any obstruction.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |