Brother P-touch PT-1180 Service Manual page 19

(2) Adhesive Base Tape Feeding (only for laminated tape cassettes)
A laminated tape cassette contains both a transparent laminate tape roll and a separate
adhesive base tape roll.
When a transparent laminate tape and an adhesive base tape pass through the contact
point (between the tape feed roller and (tape feed) sub roller), they are then bonded together
into a single, printed tape. The ink printed on the laminate tape is, therefore, sealed up with
the adhesive base tape.
(3) Ink Ribbon Feeding
As the DC motor rotates, the ribbon drive cam located at the middle of the gear train rotates
counterclockwise. When fitted on the ribbon drive cam, the ribbon take-up roll in the tape
cassette also rotates to take up the ink ribbon.
To apply proper tension to the ink ribbon between the platen roller and the ribbon drive cam,
the feed amount of the ribbon drive cam is slightly greater than that of the platen idle gear.
The difference between the tape feed speeds at the platen roller and at the ribbon drive cam
is absorbed by the clutch spring which is integrated in the ribbon drive cam and allows the
cam to slip.
In this way, the ink ribbon is kept tense, which enables the ribbon to clearly separate from
the tape at the stabilized angle after printing.
Tape feed roller
(Tape feed) sub roller
DC motor
Tape idle gear
Platen roller Roller holder ASSY
Fig. 2.1-4 Ribbon Feeding Mechanism
II-4
Ink ribbon
Thermal head ASSY
Frame
Ribbon drive cam
Platen idle gear