Service Manual
5-13
Theory of Operation
5
Print positioning and printing
With the paper into the paper path, the paper clamp bar, pulling the sheet of
paper, is shuttled to a point just in front of the thermal head. This is the print
start position. The thermal head, in turn, is lowered to sandwich the transfer roll
and paper between the thermal head and the platen. The pinch roller is moved
forward against the platen to help hold the paper evenly against the platen.
During printing the timing belts pull the paper and transfer roll past the thermal
head. The pickup roller of the transfer roll is driven, against a torque limiter,
with just enough force to keep the transfer roll taut. The movement of the paper
moves the transfer roll. As the paper and transfer roll move past the thermal
head, the thermal head selectively energizes its elements to transfer dye to the
paper, line by line, from the first panel of the transfer roll, yellow. Once the
entire page has passed by the thermal head, the thermal head is raised and the
pinch roller is moved rearward to allow the paper clamp bar past. The paper
clamp bar continues to the print start position and then the thermal head lowers
back to its print position and the pinch roller moves forward against the platen.
The print process repeats with the next color panel, magenta. This process then
repeats one more time for the remaining cyan panel. It may also repeat once
more for the black panel of 4-Color Transfer Rolls.
Figure 5-8. Paper positioning and printing
8850-19
Printhead in print position
Pinch roller in print position
