Oki ML520 - Manual (Page 73)

Page: 53
Service Guide ML520/521
Chapter 2 Principles of Operation
Ribbon Drive Operation
The ribbon drive mechanism feeds the ribbon in synchronization with the spacing operation. The force
required to drive the ribbon is obtained from the space motor.
The ribbon drive mechanism is composed of the items listed below.
Ribbon Drive Gear Assembly
Ribbon Gear
This gear is located on the space motor assembly
Ribbon Cartridge
A continuous loop ribbon with uni-directional feed is used. Ink is supplied from an ink tank,
which is built into the ribbon cartridge.
When the space motor turns, the ribbon gear on the spacing motor shaft rotates. The rotation is
transmitted via a combination of gears, from the ribbon drive gear assembly to the drive gear in the ribbon
cartridge.
Although the space motor moves in both the forward and reverse directions during bi-directional printing,
the gears in the ribbon drive assembly maintain uni-directional ribbon feed by switching the rotation
direction of the gears.