Swecoin TTP 5200, Service Manual

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December 2001 TTP 52x0 Series Kiosk Printer— Service Manual 7
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 rollers in the presenter module. The presenter motor (DC-motor) drives the
rollers.
During the printing procedure, the firmware runs the presenter motor slowly until the
presenter sensor detects the leading paper edge. The presenter feed rollers then stops
and holds the top of the document. Deflection ribs in the presenter module assist in
forming a document loop within the printer when the firmware postpones the presentation
until printing and cutting is completed. The presenter motor will then present the
document to the customer. If so selected by the application program, the presenter feed
rollers 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.