Adjusting And Resetting The Printer; Platen Gap Adjustment - Epson LQ-670 Service Manual

LQ-670 Service Manual

4.2 Adjusting and Resetting the Printer

4.2.1 Platen Gap Adjustment

This adjustment consists of platen parallelism adjustment and platen gap adjustment. Parallelism
adjustment is to adjust parallelism of track(CR guide shaft) that platen roller and print head moved.
Since the core of parallelism adjustment bushing is tilted to the CR guide shaft, it is possible to move the
CR guide shaft closer to or away from the platen roller by rotating the bushing. Parallelism adjustment is
performed by equalizing the gap between the platen roller and CR guide shaft in the right and left edges of
the printable area.
On the other hand, the platen gap adjustment is to set the gap between the platen roller side and print
head at the specified value. Since the core of the CR guide shaft is also tilted, it is possible to move the
print head closer to or away from the platen roller by rotating the shaft.
1. Remove the upper housing.
2. Remove the paper eject unit.
3. Remove the print head.
4. Remove the ribbon mask.
5. Install the print head.
6. Set the adjust lever to the "0" column position.
7. Loosen a little bit the hexagon nut securing the PG adjust lever and CR guide shaft.
8. Rotate the CR guide shaft so that the big hole of the countersinking located on the right edge of the CR
guide comes towards you.
9. Move the carriage unit to the left edge.
10. Set the thickness gauge to 0.43mm and insert it vertically between the print head and platen roller.
11. Insert the screwdriver into the hole of the countersinking located on the right edge of the CR guide
shaft and rotate the screwdriver until the platen roller and print head touches each other lightly.
12. Move the carriage unit to the right edge.
13. Insert the thickness gauge between the print head and platen roller.
14. Continue performing adjustment steps 8 to 12 rotating the parallelism adjustment bushing until the
parallelism gap of right and left becomes under 0.02mm.
15. When the parallelism gap of right and left becomes less than 0.02mm, move the carriage unit to the
center position of the printable area.
16. Insert the thickness gauge between the print head and platen roller, and rotate the CR guide shaft so
that the platen gap becomes 0.435
17. After the adjustment is over, tighten the hexagon nut securing the adjust lever.
18. Install the ribbon mask.
; Do not rotate the platen roller during this adjustment.
4-2
(Refer to section 3.2.4)
(Refer to section 3.2.5)
(Refer to section 3.2.2)
(Refer to section 3.2.3)
0.015mm.
CAUTION
Figure 4-1. Platen Gap Adjustment
Rev. A