Head Overheat Alarm Processing - OKIDATA ML590 Service Manual

Page: 66
Service Guide ML590/ML591
Chapter 2 Principles of Operation

Head Overheat Alarm Processing

Two thermistors are used to monitor the printhead temperature. One is contained in the printhead
and the other in the printhead driver. The voltage of the TSD signal is monitored at the MPU A/D
port to control the pass number and print method (unidirectional / bi-directional) at each of seven
levels. If the printhead temperature exceeds 110 degrees Celsius, the printer will switch to
unidirectional print. If the temperature exceeds 115 degrees Celsius, printing will stop. Once the
printhead cools, printing will resume.
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