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)

G e a r 4 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,

Ink Ribbon

 

Ribbon PressureI’

Mask

.ake

Gear (21, \

Ribbon

Driving Gear

-

Figure 6-21. Ribbon Advance Mechanism

6-18

Epson FX-870/1170