Roland Advanced Jet AJ-1000 Service Notes page 189

Make sure the tension is between 0.97kgf and 1.189kgf
when Belt makes contact with the the dent part which is
hooked the spring.
Attach SOLENOID CUSHION (P/N.22265241)
onto the top of ST-001 to make a measurement
easier.
Adjust the tension by Adjustment Screws if the tension is not
in the range between 0.97kgf and 1.18kgf.
If it is necessary to add the belt tension, tighten up both
Adjustment Screws with the same amount.
If it is necessary to reduce the belt tension, loosen both
Adjustment Screws with the same amount.
Tighten up the 2 screws shown in the figure.
9
Measure the belt tension again and make sure the tension
10
is between 0.97kgf and 1.18kgf.
Carry out the procedure 6 - 9 again if the tension is not in
the range between 0.97kgf and 1.18kgf.
When this adjustment is finished, be sure to carry out [4-10
BELT POSITION ADJUSTMENT].
<Top View>
<Front View>
Adjustment Screw
Guide Rail
<Front View>
<Top View>
4-42
Plate
70mm
Idle Pulley Holder
70mm