Kodak NOVAJET 700 - Manual (Page 29)

Theory of Operation 2-5
NovaJet 500/630/700 Series Service Manual
THEORY OF OPERA
TION
Media Feed and Take-Up System
REFLECTOR
REFLECTOR
SENSORS
Figure 2-4. Power Feed and Take-Up System.
The media feed and take-up system comprises of two optical sensors,
two dc motors and a dryer assembly. See Figure 2-4. The NovaJet
750 uses a thermal drying system while all other models use a blower
drying system as shown above.
Motors are used to advance the media feed roll and the media take-up
roll dependant upon the signals they receive from the MPWA. The
MPWA generates the control signals for the motors from the informa-
tion it receives from the media feed and take-up sensors. The MPWA
also controls the dryer assembly. It activates only the fans required to
cover the width of the loaded media. The fan assembly also contains an
interlock circuit.
The optical sensors are designed to inform the MPWA when there is not
a proper amount of slack in the media by sensing the ‘curl’ of the media
at the bottom of its loop. This method is used so that all approved forms
of media (including transparent backlit media) is able to take advantage
of the power feed and take-up system.