EP0503871A2
Expired / Lapsed
EP
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Print gap detecting device in print head
Assignee: Brother Industries Ltd
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Filing: 1992-03-09
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Granted: —
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Expires: 2012-03-09
Abstract
Abstract Piezoelectric elements that can resonate at a certain frequency with a coil are extended and contracted as they are repeatedly charged and discharged. The extending and contracting movements of the piezoelectric elements are amplified and transmitted to move the print wires toward and away from the platen. The waveform of a voltage generated across the piezoelectric element is detected by a monitoring device. Then, the detected voltage waveform is compared with the waveform of a voltage that is produced when the print gap is proper, and lets the user to know the magnitude of the print gap between the distal ends of print wires and a platen at any time during printing operation.
Inventors
- 👤 Akira c/o Brother Kogyo K. K. Iriguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 04:23
CPC Classifications
B; B41; B41J; B41J25/00; B41J25/304; B41J25/308; B41J25/3088; B41J2/00; B41J2/22; B41J2/23; B41J2/27; B41J2/295; B41J2/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A print gap detecting device for detecting a print gap between a distal end of a print wire and a platen in a dot impact printer having an actuator for actuating the print wire with amplified extending and contracting movements of a piezoelectric element by virtue of a motion transmitting mechanism responsive to a voltage applied thereto, the detecting device comprising: monitoring means for monitoring a waveform of the voltage across the piezoelectric element; and determining means for determining a magnitude of the print gap based on the waveform of the voltage.
Claim 2
Dependent Claim
92 words
A print gap detecting device for detecting a print gap between a distal end of a print wire and a platen in a dot impact printer having an actuator for actuating the print wire with amplified extending and contracting movements of a piezoelectric element by virtue of a motion transmitting mechanism responsive to a voltage applied thereto, the detecting device comprising: monitoring means for monitoring a waveform of the voltage across the piezoelectric element; and determining means for determining a magnitude of the print gap based on the waveform of the voltage.
Claim 3
Dependent Claim
39 words
The device according to claim 1, wherein said determining means comprises comparison means for comparing a level of the waveform of the voltage with a reference voltage level developed across said piezoelectric element when the print gap is proper.
Claim 4
Dependent Claim
39 words
The device according to claim 2, further comprising alarming means for alarming an abnormality of the print gap when said determining means ind icates that the level of the waveform of the voltage is out of a predetermined range.
Claim 5
Dependent Claim
51 words
The device according to claim 1, wherein said determining means comprises observing means for observing if a peak level of the waveform of the voltage appears after elapse of a predetermined period of time from a time when the print wire is instructed to perform a contracting movement by said actuator.
Claim 6
Dependent Claim
39 words
The device according to claim 4, further comprising alarming means for alarming an abnormality of the print gap when said observing means indicates that the peak level of the waveform of the voltage appears within a predetermined time range.
Claim 7
Dependent Claim
119 words
A printer comprising: a platen; a plurality of print wires, each having a distal end; a plurality of piezoelectric elements coupled in one-to-one correspondence to said plurality of print wires, each piezoelectric element being extended and contracted in response to a voltage applied thereto; motion transmitting means for amplifying extending and contracting movements of each of said plurality of piezoelectric elements; and print gap detecting means for detecting a print gap between the distal end of each print wire and said platen, said print gap detecting means comprising monitoring means for monitoring a waveform of the voltage across the piezoelectric element, and determining means for determining a magnitude of the print gap based on the waveform of the voltage.
Claim 8
Dependent Claim
119 words
A printer comprising: a platen; a plurality of print wires, each having a distal end; a plurality of piezoelectric elements coupled in one-to-one correspondence to said plurality of print wires, each piezoelectric element being extended and contracted in response to a voltage applied thereto; motion transmitting means for amplifying extending and contracting movements of each of said plurality of piezoelectric elements; and print gap detecting means for detecting a print gap between the distal end of each print wire and said platen, said print gap detecting means comprising monitoring means for monitoring a waveform of the voltage across the piezoelectric element, and determining means for determining a magnitude of the print gap based on the waveform of the voltage.
Claim 9
Dependent Claim
39 words
The printer according to claim 6, wherein said- determining means comprises comparison means for comparing a level of the waveform of the voltage with a reference voltage level developed across said piezoelectric element when the print gap is proper.
Claim 10
Dependent Claim
38 words
The printer according to claim 7, further comprising alarming means for alarming an abnormality of the print gap when said determining means indicates that the level of the waveform of the voltage is out of a predetermined range.
Claim 11
Dependent Claim
51 words
The printer according to claim 6, wherein said determining means comprises observing means for observing if a peak level of the waveform of the voltage appears after elapse of a predetermined period of time from a time when the print wire is instructed to perform a contracting movement by said actuator.
Claim 12
Dependent Claim
39 words
The printer according to claim 9, further comprising alarming means for alarming an abnormality of the print gap when said observing means indicates that the peak level of the waveform of the voltage appears within a predetermined time range.
References Cited (Backward Citations)
No citation records indexed.
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