Epson FX-870 Service Manual

Principles of Operation
Ribbon Advance Mechanism
The ribbon is held between the ribbon advance roller (ribbon driving gear) and the ribbon pressure
roller. When the carriage moves on the shaft, the timing belt turns the belt driven pulley, and the
torque is transmitted to the ribbon driving gear through the gear train. The ribbon driving gear
rotates counterclockwise no matter what direction the carriage moves, because the planetary gear
is used in the gear linkage.
Table 6-2. Ribbon Advance Gear Linkage
Direction of Carriage Movement
Gear Linkage
Left to right
Belt-driven pulley 3 Gear 1 + Gear 2 3
(indicated bv the black arrow)
Ribbon-driving gear
Right to left
Belt-driven pulley ti Gear 1 c3 Gear 3 @
(indicated by the white arrow)
Gear4 C=,
Ribbon-driving gear
The ribbon brake spring, attached to the exit slot of the cartridge case, prevents slack in the ribbon
and keeps the ribbon tension at an appropriate level. The ribbon mask prevents the ribbon from
brushing against the paper.
Ribbon Advance Roller,
Ribbon Pressure
Ink Ribbon
I’
Mask
Gear (21,
\
Ribbon
Driving Gear
.ake
-
6-18
Figure 6-21. Ribbon Advance Mechanism
Epson FX-870/1170

Epson FX-870 Specifications

General

Brand	Epson
Model	FX-870
Category	Printer
Language	English