HP 250C - Manual (Page 48)

5Ć6 Functional Overview C4699Ć90000
Providing a Force on Top ofthe Media
Bail
The bail provides a normal force on top of the media. Unlike on the DesignJet 220, there is
no bail sensor on the DesignJet 230 and 250C and DesignJet 330 and 350C.
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. The mechanism is different from that used in
the DesignJet 220. The new cableĆbased design eliminates the torque on the axle ofthe
bailĆlift cam and thus improves reliability. The new mechanism is also more accessible.
(Removal ' page 6Ć29.)
Moving the Carriage
CarriageĆDrive Mechanics
Motor, Belt and Pulley
D The carriage (YĆaxis) drive consists ofa DC motor directly driving a single belt and the
carriage. This replaces the dualĆbelt system ofthe DesignJet 220.
D The motor assembly itselfprovides the tension needed on the belt, eliminating the need
for a separate pulley tensioner.
D The belt clamps itselfto the carriage; there are no separate belt clamps.
D The interface between the motor shaft and belt is friction based.
D You can remove the belt without having to remove the pulley on the left end of the belt.
Carriage Guidance
The carriage moves along on just one stainless steel slider rod. It is guided by two integrated
bronze bushings, which are selfĆlubricating, and a back wheel.
Positional Feedback
An encoder strip, similar to that on the DesignJet 650C, provides feedback on the position of
the carriage. The strip does not require adjustment.
Take care not to cut yourself on the encoder strip inside the plotter.