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# Method of Determining the Temperature of a Print Head

IP.com Disclosure Number: IPCOM000061701D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

IBM

## Related People

Alexander, RW: AUTHOR [+1]

## Abstract

The temperature of a print head is calculated by considering the coil to heat sink temperature differential and the heat sink temperature, considering the air flow over the heat sink as related to the speed of the print head. Thus, the temperature of the print head is more accurately defined by maintaining separate hypothetical temperatures for the hottest coil and the heat sink, making this method suitable for use where the thermodynamic characteristics of the material between the coils and the heat sink is unknown. Coil cooling is a function of the time and the temperature differences between the coil and the heat sink.

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Method of Determining the Temperature of a Print Head

The temperature of a print head is calculated by considering the coil to heat sink temperature differential and the heat sink temperature, considering the air flow over the heat sink as related to the speed of the print head. Thus, the temperature of the print head is more accurately defined by maintaining separate hypothetical temperatures for the hottest coil and the heat sink, making this method suitable for use where the thermodynamic characteristics of the material between the coils and the heat sink is unknown. Coil cooling is a function of the time and the temperature differences between the coil and the heat sink. A memory in the printer maintains the hypothetical temperatures for the heat sink and for the hottest coil using two three-byte counters (one for coil temperature, and one for heat sink temperature) which are periodically updated whether the printer is printing or idle with values representing the temperature change during the time interval. The temperature of the print head increases during wire firing. For each wire fired, a value is added to the counters. The value added is determined by the total number of wires firing simultaneously, and it is analogous to the actual temperature increase. The heat sink counter is incremented by a value equivalent to the actual heat sink temperature increase for each wire fired. Conversely, cooling of the heat sink during this same time interval is repres...