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# Measuring the Flight Time of Print Hammers in Impact and Line Printers

IP.com Disclosure Number: IPCOM000041324D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 20K

IBM

## Related People

Matthaei, HD: AUTHOR

## Abstract

Any one of the, say, 132, print hammers of a print hammer bank is fired. The record carrier, the ribbon and a revolving type steel band (not shown for clarity) are arranged between the print hammers and the platen 200. The flight time of print hammer 60 from the firing time to the impact time is TF, the travel time of the sound wave in the platen from the impact point to a sensor 1 and a sensor 2 is 201 TL1 and 202 TL2, respectively. After the time T1 has elapsed from the firing time of the print hammer, sensor 1 emits a signal, while sensor 2 emits a signal after the time T2. In the relation T1 + T2 = TL1 + TL2 + 2 TF TL1 + TL2 is a constant K which corresponds to the travel time of the sound wave through the platen over the distance between sensor 1 and sensor 2. TF = T1 + T2 - K.

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Measuring the Flight Time of Print Hammers in Impact and Line Printers

Any one of the, say, 132, print hammers of a print hammer bank is fired. The record carrier, the ribbon and a revolving type steel band (not shown for clarity) are arranged between the print hammers and the platen 200. The flight time of print hammer 60 from the firing time to the impact time is TF, the travel time of the sound wave in the platen from the impact point to a sensor 1 and a sensor 2 is 201 TL1 and 202 TL2, respectively. After the time T1 has elapsed from the firing time of the print hammer, sensor 1 emits a signal, while sensor 2 emits a signal after the time T2. In the relation T1 + T2 = TL1 + TL2 + 2 TF TL1 + TL2 is a constant K which corresponds to the travel time of the sound wave through the platen over the distance

between sensor 1 and sensor 2. TF = T1 + T2 - K. Values T1 and T2 may be measured, for example, by means of a counter, so that the flight time can be automatically determined under computer control. Thus, flight time deviations may also be determined and compensated for by shifting the firing times of the print hammers, using a microprocessor.

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