The clear top tape (light blue line) is usually completely clear.

The tape is empty and the zebra stripes indicates it to the user.

The thermal ink tape gets unrolled and again rolled onto another roller.

In the printing zone, a single column of heat "pixels" heats the thermal ink (red line) and sticks it to the clear top tape (blue line).

The clear top tape than gets laminated with the white backing (white line).