Swecoin TTP 5000, Service Manual

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TTP 5000 Series Kiosk Printer Sub-system — Service Manual Edition B, May 97 8
2.1 Paper handling
The print module has a stepper-motor that drives a platen. The thermal printhead
presses against the platen with the temperature sensitive paper in-between. The platen
pulls the paper from the supply roll and feeds the paper through the cutter module and
up to a couple of feed rolls in the presenter module. The rolls are driven by the presenter
motor (DC-motor).
During the printing procedure, the application program runs the presenter motor slowly
until the presenter sensor detects the leading paper edge. The top of the document is
then arrested by the presenter feed rolls. Deflection ribs in the presenter module assist in
forming a document loop within the printer if the application program postpones the
ejection until printing and cutting is completed. The presenter motor will then eject the
document. If so selected by the application program, the presenter feed rolls can be set
at continuous feed-through during printing, for example, when very long documents are
being printed.
The presenter sensor also detects when the trailing document edge leaves the exit slot.
The combined paper-end and TOF sensor is actuated by light reflection against the back
of the paper. If the light reflection disappears, but returns within a specified number of
paper-feed motor steps, this means that a pre-printed black mark is detected. If the light
does not return before this number of motor steps has been effected, this will be
interpreted as paper end.