Paper Jam Detect Circuit - Toshiba e-STUDIO170F Service Manual

7.3.13

Paper Jam Detect Circuit

The paper jam detect circuit consists of the Engine-CPU (IC37) as central component. It detects the
transport status of recording paper by judging the outputs of the paper position sensor connected to
CN21 and the paper exit sensor connected to CN20.
When recording paper is transported to the printing position by the RX motor, the actuator of the paper
position sensor is pushed down by the recording paper to turn on the sensor. This causes the PS1X
signal to go LOW and input to the Engine-CPU to detect that the transport of recording paper to the
printing position is completed.
After the start of printing, the recording paper is further transported. At this time, the recording paper
length is judged by measuring the time for which the PSX1 signal is at LOW level. If the PS1X signal
does not return to HIGH level even after a fixed time has elapsed, the occurrence of a recording paper
jam will be assumed.
When recording paper is transported to the fuser by the RX motor, the actuator of the paper exit sensor
is pushed down by the recording paper to turn on the sensor. This causes the PS3 signal to go LOW
and input to the Engine-CPU to detect that the recording paper is being transported in the fuser. When
the recording paper then goes through the fuser, the PS3 signal goes HIGH to detect the exit of the
recording paper. If the PS3 signal does not return to HIGH level even after a fixed time has elapsed, the
occurrence of a recording paper jam will be assumed.
Signal Name
PS1X
PS3
e-STUDIO170F Circuit Description
Main PBA
+5V1
PS1X
74
IC37
Engine-CPU +5V1
PS3
83
Type Active
I L Printing position detect signal
I L Paper exit detection signal
R106
1
Paper position
sensor
2
Fuser
R113
1
Paper exit
3
sensor
2
Fig.7-31
Description
7 - 40
Destination
Paper position
sensor
Paper exit
sensor
January 2005 © TOSHIBA TEC