Causes & Countermeasures - Brother mfc8440 Service Manual

3.3.3 Causes & countermeasures
The causes for paper jam problems vary depending on the location of the paper jam. When a
paper jam occurs inside the machine, you have to find the location of the paper jam first,
remove the jammed paper and then take the appropriate countermeasure referring to the table
below;
Problem
Jam when the
machine is turned
on.
Top of paper
stopped at 350mm
from the second exit
roller. Next paper is
not fed.
Bottom of paper
stopped around the
transfer roller.
Top of paper
stopped between the
paper feed roller and
the pick-up roller.
Top of paper
stopped at 50mm
from the contact
point of the heat
roller and pressure
roller.
Jam after paper is
ejected.
Type of Jam
Paper stuck
Jam caused by
paper length
detected as longer
than 400mm (16 in).
Jam caused by
paper length
detected as shorter
than 80mm.
Jam caused by a
paper feed delay.
Jam caused by the
paper not being
sensed when ejected
from the paper eject
sensor.
Jam caused by the
paper not being
sensed when ejected
from the paper eject
sensor.
6-17
MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN
Cause
The front registration
sensor or paper eject
sensor is turned on.
The front registration
sensor is not
returning properly
and is not turning off.
The front registration
sensor was turned
off early.
Malfunction of
actuator or hardware
noise.
Paper was not fed in
at the proper timing
due to paper dust or
wear of the rubber
pick-up roller.
The paper eject
sensor is not working
properly and has not
turned off. (single
printing)
The paper eject
sensor or front
registration sensor is
not working properly
and has not turned
off. (continuous
printing)
SERVICE MANUAL
Remedy
Remove the paper
inside the machine.
If there is no paper,
check the suspect
sensors referring to
'3.9 Sensor
OperationaI Check'
in Chapter 7.
Check front
registration sensor
motion referring to
'3.9 Sensor
OperationaI Check'
in Chapter 7.
Check the front
registration sensor
referring to '3.9
Sensor OperationaI
Check' in Chapter 7.
Remove the paper
dust attached to the
pick-up roller. If the
rubber is worn out,
replace it with a new
one.
Check sensor motion
referring to '3.9
Sensor OperationaI
Check' in Chapter 7.
Check sensor motion
referring to '3.9
Sensor OperationaI
Check' in Chapter 7.