Intermec EasyCoder 301 – Service Manual Ed. 3
35
Chapter 7 Print Unit
7.7
Headlift
Mechanism
Description
The headlift mechanism does not really lift the printhead (which in
fact is done by a spring fitted at the front of the printhead bracket),
but by operating the handle the printhead can be opened or closed.
The open position is used for paper and ribbon load, for cleaning,
and for printhead replacement.
In closed position, two adjustable knobs engage the rounded leaf
spring at the top of the printhead bracket, thereby pressing the
printhead against the platen roller.
This pressure is important
• for the transfer of heat from the resistor elements on the
printhead substrate to the transfer ribbon or direct thermal paper,
• for the transfer of melted ink from the ribbon to the receiving face
material,
• and for the friction between the back side of the paper web and
the platen roller.
The handle is fitted to the same shaft as the two adjustable knobs.
The shaft runs through the centre-line wall into the electronics
compartment and through a hole in the CPU board. On the CPU
board, the headlift sensor is fitted so light between the emitter and
receiver can pass through a drilled hole in the shaft when the
printhead is closed. When the shaft is rotated towards open position,
the shaft blocks the light. Note that if the headlift handle is rotated
180 degrees to an upright position, the sensor will erroneously
indicate printhead closed.
Opening the printhead
Closing the printhead
Handle
Shaft
Adjustable knobs
