SX
™
Service and Maintenance Manual 1-3 960714-02B © 2007 I2407
SECTION 1 – INTRODUCTION
THEORY OF OPERATION
GENERAL
The Sharp SX™ is controlled by a PLC
(Programmable Logic Controller). The PLC
receives input from the operator touchscreen to
control a stepper drive motor and an electric eye
sensor on the bag feeder output end.
The Sharp SX™ is equipped with a sensor on the
pressure jaw which can detect an obstruction. If an
object triggers the sensor, the pressure jaw motor
will reverse, and place the bagger into a fault. A
message appears on the control panel displaying
the jaw fault, allowing the operator to clear the seal
area and restart the bagging cycle.
Note: the Sharp SX™ is not designed to interface
with automatic infeed units such as counters,
scales, or infeed conveyors.
•
The Sharp SX™ uses pre-opened Sharp EZ-
Bags
. The bags are dispensed through the
powered drive rollers.
•
A constant stream of air opens (inflates) the
bag, preparing the bag to be loaded.
•
Product is loaded into the bag.
•
Once the bag is loaded, the operator cycles the
machine (either by foot control, optional dual
optical palm buttons, from the Touchscreen or
the machine can be set on automatic cycle) to
seal the bag.
•
The pressure jaw closes and grips the bag.
The impulse sealer heats up and seals the bag
while the power drive rollers reverse to
separate the bag at the perforation.
•
An electric eye is used to sense the trailing
edge of the bag. Hang holes, vent holes, etc.
must be prevented from passing over the
electric eye as this will send a false signal to
the PLC. To prevent this, the electric eye has
been designed to be off center of the bag,
however, in some cases the bags may have to
be repositioned when larger hang holes, vent
holes, etc. are present (see
Loading Bag Film
).
•
When the bag is sealed and seal dwell is
complete, the pressure jaw opens.
•
The Printhead is lowered and the bag is
indexed forward at printing speed until the label
is completed. The Printhead is raised and the
balance of the bag length is indexed forward at
full index speed (bagger speed). (
Note: This
step occurs only if model is equipped with an
imprinter)
•
As the bags are indexed, the Material Unwind
Shaft will spin allowing the bags to be pulled
from the roll. The Material Unwind Shaft is
comprised of a Roll Tensioner with
compression spring, Core Chuck, and a torsion
spring. When the roll of bags is loaded onto
the machine, pressure is applied to the Roll
Tensioner which in turn applies pressure to the
roll side plate creating a kind of slip clutch. The
pressure that is applied to the Roll Tensioner is
directly proportional to the type and thickness
of the material being used. As this pressure
increases the amount of tension on the web
also increases. The appropriate amount of
pressure that should be applied to the Roll
Tensioner can be found using trial and error.
•
The constant stream of air inflates the bag,
preparing the bag to be loaded.
The Sharp SX
TM
is equipped with a jaw
obstruction detection sensor. This sensor is
not designed, nor intended, to be a safety
sensor.
WARNING
Figure 1-4. Sharp SX™
