Printronix L5535, Maintenance Manual

Page: 156 / 358

II–156
Chapter 8
Control System Descriptions
Head Temperature Monitoring
The printer uses a thermistor (HTS) to monitor the LED head temperature to
avoid excessive printhead temperature during printing, When the LED head
temperature rises to 45°C, the printer considers it an error, stops printing
operations, cools the LED head with a heat pipe and a head cooling fan, waits
until the LED temperature falls below 45°C, and goes into the online idling
state to become ready to resume printing.
The LED head output light intensity will also lower when the LED head
temperature rises. Therefore, the head thermistor also checks whether a
temperature of 35°C is exceeded. If the LED head temperature rises above
35°C, the LED illumination time is increased by 5% (the normal illumination
time is equivalent to 25% of the raster cycle).
LED Head
Head Thermistor
Heat Pipe
Head
Cooling
Fan
Fin