Mad Phil gave me his Brother PT-1090 labeler, which I’ve been using rather often of late. The white tape cartridge (the TZ flavor) ran out, giving me the opportunity to pry it apart:
Surprisingly, a few small pins molded into the cover, plus a few obvious latches, hold it together without a trace of glue or thermal welding.
A detail of the little factory that assembles the label from several parts:
Colored paper tape unwinds from the lower right and the top plastic layer from the lower left. Tape with thermal dye unspools from the upper left, the printhead (in the printer) heat-transfers pixels to the plastic tape in the opening right of center along the top, and the roller at the top right joins the just-printed plastic layer to the slightly sticky front surface of the paper tape. The used imaging tape respools in the gray cylinder near the middle.
For those concerned with privacy, that gray spool of used imaging tape contains everything you’ve printed in order:
I thought the thermal dye was part of the transparent tape cover layer, but in retrospect that doesn’t make sense: the printed tape would turn black in hot environments like, say, your car. So the printer must transfer the dye from a separate tape.
The knockoff “ESD” tape cartridges from Amazon seem to have a slightly different tape path, probably to work around Brother’s patents. I’ll pry one of those apart in due course.