Roland Advanced Jet AJ-1000 Service Notes page 192

Rotate Adjustment Screw clockwise (to the direction to
tighten) when Belt is in the upper position from the center of
Drive Pulley shown in the figure.
There is another screw for fixing Drive Shaft
Support on the machine with the Servial Number
from ZU50190 to ZU50220.
Screw
Rotate Adjustment Screw CCW (to the direction to loosen)
when Belt is in the lower position from the center of Drive
Pulley shown in the figure.
There is another screw for fixing Drive Shaft
Support on the machine with the Servial Number
from ZU50190 to ZU50220.
Screw
NG
NG
4-45
Adjustment Screw
Adjustment Screw