Intermec EasyCoder 501 XP Service Manual page 44

Chapter 7 Transfer Ribbon Mechanism
7.2 Ribbon Supply
Unit, cont.
Grub Screw (M4)
Sleeve
Brake Spring
(differs between
models)
Bearing
1
/. Refer to Appendix 2 for a descrip-
tion of how to check the brake torque.
42
Working Principles
The ribbon supply is braked by a spring affi xed to the printer's
center section, partly enveloped by a sleeve affi xed to the shaft.
Initially, the spring expands towards the inner wall 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. The expected interval between replacing the grease is 8 to
10 million print cycles.
When the rotating force ceases, the spring tends to pull back the
ribbon, keeping it tight.
The code disc is only used in connection with the optional ribbon
low sensor (see Chapter 12), but is nevertheless always fi tted.
Flange
Bearing
Shaft
Dismantling
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.
E-ring
Grooves
Code Disc
Intermec EasyCoder 501 XP & 601 XP – Service Manual
1
. The sleeve is fi lled
E-ring
Plastic Snap Ring
Hub assy.