Canon fax basic 2000 Manuale Di Servizio

4–19

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RECORDING SECTION

3.3

Detection of Recording Paper Jams

A “recording paper jam” is a state where loaded recording paper has

jammed inside the unit without being picked up, fed or ejected. Recording

paper jams are detected by the ON/OFF timing of sensors that detect the

presence of recording paper. Generally, light-transmitting type photo-inter-

rupters which are a kind of optical sensor are used for detecting the pres-

ence of recording paper. When the light that is irradiated from the light-

emitting section of the photo-interrupter is detected by the light-receiving

section, the sensor turns “ON.” Alternately, when light is blocked by the

actuator and cannot be detected by the light-receiving section, the sensor

turns “OFF.” Changing of the ON/OFF state of the sensor in this way is

used for detecting the presence of recording paper.

Fig. 4-21 Photo-interrupter

Generally, the following four types of recording paper jams occur:

• Pickup jam

• Feed jam

• Fixing unit wrap-around jam (only in case of LBP)

• Eject jam

Light-emitting
section (LED)

Light-receiving section
(photo-transistor)

Actuator