Printhead - OKIDATA ML320 Service Manual

Page: 31
Service Guide ML320/ML321
Chapter 2 Principles of Operation

2.4.01 Printhead

The printhead used by the printer is a highly efficient, stored-energy type. Power is not consumed
until the pins are activated. Printhead life is approximately 200 million characters.
The printhead is designed with nine pins, vertically aligned. Each pin is welded to an armature ring.
Behind the armature ring is a spacer ring.
Each armature has a permanent magnet behind it. The magnet attracts the armature, keeping the
pin inside the printhead. Because of the spacer ring behind the armature ring, the armature is
attracted toward the permanent magnet at an angle. A coil is wrapped around each permanent
magnet.