Panasonic FP-7742 / FP-7750 (serv.man2) Service Manual ▷ View online
3-16
3)
Toner level detection
• When the toner level sensor in the toner hopper detects no toner remaining,
and does not detect toner after continuously turning the toner bottle "Add toner"
is displayed. The copier is disabled.
The machine can be used after the user's key input.
After lighting the no toner indication, the machine stops after 300 copies.
The "Add toner" indication is cleared by replacing the toner bottle.
4)
Detecting the toner bottle position
• Insert the toner bottle in the hopper and turn to the specified position.
Accordingly, the toner bottle shutter opens and is able to add toner to the
hopper.
• The bottle home position sensor which is mounted in the toner hopper detects
the position of the toner bottle and the toner bottle stops turning at the specified
position.
Sub Assemblies
3-17
1
2
3
4
(5)
Paper transport unit and separation unit
1)
Paper transport unit
The paper transport unit transports the paper after transfer/separation. Paper
is secured by the suction fan and transferred to the fuser using the transfer
belt.
• The paper transport unit is driven by the main motor which is transmitted to
the paper transport drive gear via respective drive gears.
• The suction fan which is provided on the main body side is connected with the
paper transport duct.The suction fan holds the paper to the paper transport
belt and also removes the ozone generated by the transfer/separation corona.
• The post card kicker is provided to transfer post cards smoothly. It is fixed on
the roller of the paper transport belt and always rotates.
• The transfer/separation corona is provided with a transfer corona cleaner
motor and cleaner felt to clean the transfer corona.
Cleaner
motor
motor
Cleaner
Suction/Ozone fan
Part description
Function
1
Paper transfer belt
Transport paper to fuser.
2
Paper transport drive gear
Drive paper transport unit by copier drive gear.
3
Paper transport duct
Suction type duct (vacuum coming from suction fan
on copier frame).
4
Transfer guide
Guide plate to transfer unit from photo receptor
5
Transfer/separation
Charge paper and transfer toner from drum,
corona
discharge the paper, and separate from photo
receptor.
Transport drive gear
Pulley
Belt
Cleaner support
Cleaner home
position sensor
position sensor
3-18
2)
Operation of the separation finger
After transfering the image on the drum to the paper with the transfer corona,
the paper is separated from the drum by the separation corona.
The separation finger is provided to ensure the separation of paper from the
drum. (FP-7750/7742)
• The separation finger driving unit is provided on the sensor base. After the
timing roller turns on and the paper is transferred to the transfer unit, the solenoid
turns on and the finger solenoid lever presses the finger release lever.The
released separation finger touches the drum.
• When the front edge of the paper passes through the separation finger, the
solenoid turns off and the finger solenoid lever returns. Accordingly the finger
release lever returns and the separation finger separates from the drum.
• In order that no damage occurs on the surface of the drum, the finger is made
from a very soft, smooth material. In addition, each time the drum finger is
lifted off of the drum surface, it is moved slightly to the side by a ratcheting
cam follower, so that it does not touch the drum at the same lateral position
in succession.
Solenoid
Separation finger
Release lever
Cam
lever
lever
Cam
Solenoid lever
Pressure
spring
spring
Drum
Release spring
Drum
Sensor base
Solenoid
lever
lever
Separation finger
Shaft
Release lever
Sub Assemblies
3-19
(6)
Fuser unit
1)
Construction of the fuser
• The construction of the fuser is as follows.
Part description
Function
1
Heat roller
Fuse toner on paper by applying heat.
(Aluminum + Teflon coating)
2
Pressure roller
Fuse toner on paper by pressing paper to heat roller.
(Silicone rubber + Fluorine plastic tube)
3
Cleaning web
Clean off heat roller with non-woven cloth
impregnated with silicone oil. Coat roller with silicone
oil to reduce adhesion of toner.
4
Web pressure roller
Press cleaning web toward heat roller.
5
Fuser themostat
Safety device to detect excessive high temperature
and cut off power supply to heater lamp.
6
Fuser thermister
Temperature sensor to detect surface temperature
of heat roller and control the temperature to the
specified value.
7
Main heater lamp
Halogen lamp for fusing
Lighting : warming up, copying operation and
temperature control in stand by.
8
Sub heater lamp
Lighting : warming up faster.
9
Fuser inlet guide
Guide paper to fuser roller
10
Upper fuser separation finger Prevent paper from rolling by separating paper from
heat roller.
11
Lower fuser separation finger Prevent paper from rolling by separating paper from
pressure roller.
12
Pressure spring
Press pressure roller toward heat roller.
Heat roller temperature
374 F/190
°
C
Main heater lamp
850 W(Long one)
Sub heater lamp
550 W(Short one)
Pressure roller tension
Approx. 60 kgf
4
3
1
1
10
11
2
5
6
7
8
9
12
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