Intermec EasyCoder 501 Service Manual page 39

Chapter 7 Transfer Ribbon Mechanism
7.2 Ribbon Supply
Unit, cont.
Grub Screw (M4)
Sleeve
Brake Spring
Bearing
Flange
1
/. Refer to Appendix 2 for a descrip-
tion of how to check the brake torque.
38
Working principles
The ribbon supply unit is breaked by a spring affi xed to the print-
er's center section, partly enveloped by a sleeve affi xed to the shaft.
Initially, the spring expands towards the inner walls of the sleeve,
thereby breaking the rotation of the shaft. When the bobbin is
forced to rotate (that is, when the ribbon is unwound), the breaking
spring is compressed. After approximately half a turn, the diameter
of the spring has been compressed enough to allow the sleeve to
slip. The brake torque should be 55 ±5 Nmm
with ball bearing grease. If the brake torque deviates from the rec-
ommended value, replace the grease. We recommend Castrol Sin-
plex 2.
When the rotating force ceases, the spring tends to pull back the
ribbon, keeping it tight.
The shaft rotates in bearings fi tted into a fl ange, which is attached
to the center section by two #T20 Torx screws inserted from the
electronics compartment. Before the unit can be pulled out, the
sleeve/spring package must be removed. Use a 2 mm hexagon
wrench to loosen the grub screw.
Bearing
Shaft
Grooves
Circlip
Circlip
Code Disc
Bobbin assy.
Intermec EasyCoder 501 – Service Manual Ed. 7
1
. The sleeve is fi lled
Plastic Circlip