HP 220 - Manual (Page 40)

5Ć8 Functional Overview C3187Ć90000
Providing a Force on Top of the Media
Bail
The bail provides a normal force on top of the media. (Illustration ' page 10Ć25.) When the
pinchĆwheels grip the media and the drive roller advances it, the plotter raises the bail. This
enables the leading edge of the media to pass below the bail. The plotter then lowers the bail
and advances the media to the overdrive roller. The star wheels on the bail are coated with a
substance resistant to wet ink, so that they do not leave marks on the media.
BailĆLift Mechanism
The bail features an automatic lift mechanism driven by the media motor using a series of
gears and actuated by the cartridge carriage.
Operation
(Part illustrations ' page 10Ć25)
1 The cartridge carriage presses down on the engaging lever.
2 The engagingĆlever gear and cam gear (which are always in contact) engage the
driveĆroller gear on the left end of the drive roller.
3 The mediaĆdrive system drives the drive roller, and also the cam and engagingĆlever
gears. The autoĆcam, which is attached to the cam gear, turns with the gear.
4 The autoĆcam contacts the left bail bracket and pushes up on the bracket. As the bracket
is pushed, the bail lifts.
5 The bailĆsensor switch opens and the resulting bail logic level is sent to the main PCA.
6 The mediaĆdrive rotates the autoĆcam to a detent position. The detent position allows the
bail bracket to rest on the autoĆcam after the carriage moves away from the engaging
lever.
7 The mediaĆdrive drives the media through the media path.
8 Once the media has passed the bail, the carriage again engages the bailĆlift mechanism to
lower the bail.
Bail Sensor
The bail sensor informs the processor of the bail position (Up or Down). It is a mechanical
microswitch located on the right sideĆplate. (Illustration ' page 10Ć25)