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Print Hammer Flight Time Recorder

IP.com Disclosure Number: IPCOM000083971D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Munoz, GR: AUTHOR

Abstract

Flight time of a print hammer is measured by a counter that starts when the hammer is fired and stopped on acoustic sensing of the hammer striking the media.

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Print Hammer Flight Time Recorder

Flight time of a print hammer is measured by a counter that starts when the hammer is fired and stopped on acoustic sensing of the hammer striking the media.

When hammer circuit 1 is energized, normally charged line 2 is grounded. The consequent energization of solenoid coil 3 causes armature 4 to impel print hammer 5, for driving media 6 against the appropriate character on a rotating print wheel 7.

Meanwhile, grounding of line 2 causes B:CD counter 8 to start counting pulses from a crystal oscillator 9 and display the pulse count on B:CD display device 10. Striking of media 6 by hammer 5 is detected by an acoustical sensor 11, such as a microphone. This acoustical signal, shaped and amplified by wave shaper 12, stops counter 8. If the frequency of oscillator 9 is one megahertz, the pulse count as displayed by device 10 will represent hammer flight time in microseconds.

Counter 8 may be reset manually by depression of a reset button, not shown; or, if preferred, it may be reset automatically after a short time delay in response to the stop signal from wave shaper 12.

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