Epson 680Pro - LQ B/W Dot-matrix Printer Service Manual page 36

EPSON Stylus COLOR 680/777/77i
NOTE:
The Clutch gear is molded on
the back side of the Spur gear
35.2 such as Combination gear.
The Clutch mechanism transmits the PF motor drive to the LD roller shaft only when
the Clutch gear rotates CW direction after the Change lever releases the Clutch lever. If
the Clutch gear rotates CCW direction, the PF motor drive is not transmitted to the LD
roller. This is due to the combination of the shape of the Clutch gear and the Clutch
lock tooth such as described on the figure.
1. When the paper is advanced with the PF roller, the Change lever is set on the
Clutch lever and the Clutch is pushed down as above Step1's figure. As the
result, the Clutch gear (*1) is released from the Cluck lock tooth and the drive
from the PF motor is not transmitted to the LD roller shaft.
2. When the PF pinion gear rotates CCW direction in the above Step2's figure, the
Change lever moves to the left direction with the CCW rotation of Combination
gear 37.6, 44.4. The Clutch turns back to the engagement position by the tension
force of the Tension spring 0.143 and the Clutch gear is engaged with the Clutch
lock tooth as above Step2's center figure.
3. When the PF pinion gear rotates CW direction in the above Step3's figure, the
Change lever moves to the right direction with the CW rotation of the
Combination gear 37.6, 44.4. And the drive from the PF motor is transmitted to the
LD roller shaft via Clutch gear and Clutch lock tooth.
4. The LD roller shaft rotates about 360 degree and the Change lever push the Clutch
lever and the PF motor drive is interrupted. This position is the ASF home
position.
o Paper Return Plate (Pad holder)
Operating Principles
Step1
Spur gear 35.2
Change Lever
Clutch lever
Figure 2-9. Disengage & Clutch mechanism
Step2
Clutch gear
Tension spring 0.143
Clutch
Unlike the previous products, The Paper return plate is built in the ASF frame instead
of the Paper return lever. The Paper separation pad is also stacked on the plate.
It works with the spring force of the Torsion spring 25.7 (mounted in the ASF frame)
as following figure.
LD roller
Paper Return
Plate
ASF frame
Torsion spring 25.7
Figure 2-10. Paper Return Plate
The Paper return plate is set to return the paper to the paper stand-by position in the
ASF unit when the ASF unit is in the standby mode. When the paper is fed with the
LD roller, the Paper return plate is stored in the ASF frame by the LD roller.
Following figures show you the ASF paper loading sequence and the operation of the
each mechanism.
Overview
Step3
LD roller shaft
Clutch lock tooth
Hopper
Compression spring 4.80
Revision B
36