Domino Macrojet 2, Product Manual

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DESCRIPTION
2-16 20509 Issue 7 Jan 2018
ELECTRONIC SYSTEM
General
The electronic system contains a microprocessor, which controls the
message data input, processing and printing. It also contains circuits to
drive the solenoids in the print head and to generate d.c. power supplies.
The system consists of the following Printed Circuit Boards (PCBs):
• Universal Serial Interface
• Solenoid Driver (one or two depending on the number of print heads)
• Low Voltage Power Supply
• Motherboard.
The motherboard lies flat in the base moulding. The PCBs are plugged
vertically into it and are held in place by a foam strip in the top cover. A
single power transformer provides the low voltages required by the power
supply circuits.
The product detector is part of the electronics system. It detects the
product as it approaches the print head and provides a Print Go signal to
the printer. Macrojet 2 is able to use two detectors, with assignment of
print heads to detectors being set up with the Pocket Terminal. For details
see Pocket Terminal User's Guide, Part Number 20524.
Having been detected, the product still needs time to pass under the head
and reach the correct position for printing. The electronics system allows
for this with the Print Go delay, which is also set up using the Pocket
Terminal.
A shaft encoder is an option which enables the printer to follow line speed
variations. It has been explained how characters are printed by strokes, as
the product passes the head. If the stroke rate is fixed and the product
speed changes, the strokes will become closer or further apart. The result
is a change in the character shape. The Print Go delay is also measured in
strokes and a fixed stroke rate gives a fixed delay. Changes in the product
speed will, result in a change in the position of the printed message.
A shaft encoder is attached to the line and follows the line speed. Using it
to control the stroke rate eliminates the variations in character shape and
message position.