Printer systems 11
Printer systems
Substrate path
Description
The substrate path moves the substrate from the input spindle to the take-up reel, through the print path,
while the Carriage prints on the substrate. The objectives of the substrate path while advancing the
substrate are:
• Maintain an accurate advance
• Maintain a constant advance
• Keep the substrate flat
• Advance the substrate straight along the substrate axis
Substrate path workflow overview
The following steps describes the substrate path workflow.
1. The substrate is loaded onto the Input Spindle (1) which is driven by the rewinder mechanism to pro-
vide back tension to the media. The media is fed through the entry platen, around the Drive Roller (2),
under the Pinchwheels (3), over the printzone and Overdrive (4) and finally the media is either left
free or collected in the take-up reel.
2. The rewinder has a motor that primarily acts as a brake to maintain tension on the media.
3. The drive roller also has a motor, and is the primary component that advances the substrate. The substrate
is pressed to the drive roller by the pinchwheels, ensuring a smooth substrate advance. The motor receives
feedback from an encoder located at the left side of the roller, inside a protected enclosure on the left of
the left sideplate.
4. The surface of the substrate path where the substrate is printed is called the print platen. The print platen
is designed to give minimal resistance to the substrate advance, and includes suction holes which apply
vacuum to the substrate.
5. The vacuum, is calibrated according to the substrate type and print options used, it draws the substrate to
the print platen, making sure that the substrate is flat. The media is also under the dryer when it is in the
print zone.
6. The area of the platen in front of the print zone holds the overdrive wheels. This area also has vacuum to
ensure traction over the wheels, which are connected to the drive roller through a set of gears. The over-
drive wheels help to remove the substrate from the print zone during the substrate advance.
7. After the platen, the substrate goes through the curing zone and finally leaves the printer, either to be col-
lected on the take-up reel or to be cut.
8. The printer detects and controls the substrate’s advancement. The OMAS sensor, located on a special cut-
out section of the print platen, is a sensor which is able to detect very small errors in the advancement of
the media. These advancement errors are communicated to the motors on the driver roller and small cor-
rections adjustments are applied to the movement of the substrate.
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