Service manual

Service Manual 5-3
Theory of Operation 5
During printing, the print engine moves the paper past the thermal head three times.
During each pass, individual thermal head elements melt tiny dots of wax from the
transfer roll's colored bands; first from the yellow band, then the magenta band, and
finally, cyan. The three overlaid colors combine on the paper to produce a complete
color image. After the three passes, the finished copy is ejected from the printer. The
wax transfer roll is supplied on one spool, feeds past the thermal head and drum for
printing, and collects on a take-up spool. Note that every three bands of the used transfer
roll contains a negative impression of the printed image; this is somewhat analogous to a
photographic negative.
Figure 5-1. The thermal-wax transfer print process
8345-08A
IMAGE
IMAGE
Supply spool Mylar film
impregnated
with bands of
colored wax
Take up spool
Thermal head
Paper
Drum