Ribbon Drive Mechanism / Operation - Oki ML390 Service Manual

Page: 31
Service Guide ML390/391
Chapter 2 Principles of Operation

2.4.03 Ribbon Drive Mechanism / Operation

NOTE:
The ribbon drive gear assembly is secured to the top of the spacing motor assembly by the four claw tabs.
The ribbon drive mechanism drives the ribbon in sync with the spacing operation. The mechanism is
driven by the spacing motor.
The ribbon drive mechanism consists of the following items.
· Ribbon Drive Gear Assembly
· Ribbon Gear
The gear is attached to the spacing motor.
· Ribbon Cartridge
Ribbon Cartridge
A uni-directional feed, continuous ribbon is used. The ribbon is replenished by a built-in ink tank in the
ribbon cartridge.
Ribbon Feed Operation
As the spacing motor rotates, the ribbon gear (on the spacing motor shaft) turns the drive gear in the
ribbon cartridge via the ribbon drive gear assembly. As a result, the ribbon is moved.
In bi-directional printing, the ribbon gear rotational direction reverses each time the direction of the
carriage movement reverses. In this case, the gears in the ribbon drive gear assembly move the position
of an intermediate idler gear, causing the ribbon to feed in one direction.