HP V8.5 - Manual (Page 54)

T H E O R Y O F O P E R A T I O N
5
5 - 10 V8.5e Rev 2.2.2002
Film media
When the plotter is set to film mode, the strobe length is increased
to accommodate the thicker media. The plot speed is set to
1.0 inch per second to allow the longer strobe length and to maintain
plot quality.
5.5 MEDIA SENSORS
The top-of-form (also known as the “I-mark”) sensor and the media
sensor are contained on a media sensor board .
The top-of-form sensor consists of a focused infrared beam and
receptor that reacts to black top-of-form marks. The receptor sends
a “stop form feed” command to the logic circuitry if a mark stops
the beam from reflecting back into the receptor.
The paper sensor consists of an unfocused infrared beam and
receptor. If the receptor receives enough reflected light, the receptor
sends no command. If the reflected light is below the required level
the receptor sends a “media out” command to the logic circuitry
and plotting stops. The “no media” indicator is displayed on the
control panel.