Panasonic FP-7742 User manual

Service Manual
ORDER NO. OED9607317C1
Plain Paper Copier
FP-7742/7750
© 1996 Matsushita Electric Industrial Co., Ltd.
All rights reserved. Unauthorized copying and
distribution is a violation of law.
FP-7742/7750 Service Manual
(General)

This service information is designed for experienced repair technicians only and
is not designed for use by the general public.
It does not contain warnings or cautions to advise non-technical individuals of
potential dangers in attempting to service a product.
Products powered by electricity should be serviced or repaired only by experienced
professional technicians. Any attempt to service or repair the product or products
dealt with in this service information by anyone else could result serious injury or
death.
For U.S.A
This equipment has been tested and found to comply with the limits for a Class A
digital device, pursuant to part 15 of the FCC Rules. These limits are designed
to provide reasonable protection against harmful interference when the equipment
is operated in a commercial environment. This equipment generates, uses, and
can radiate radio frequency energy and, if not installed and used in accordance
with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to
cause harmful interference in which case the user will be required to correct the
interference at his/her own expense.
Any unauthorized changes or modifications to this equipment would void the
users authority to operate this device.
This manual was developed and is supplied to authorized servicing dealers by
Panasonic Communications & System Co. for the sole purpose of providing
information necessary for the equipment's proper support. It is intended that this
information be confidential and may not be reproduced without prior written consent
from Panasonic Communications & Systems Co. Panasonic Communications &
Systems Co. reserves the right to change any information enclosed herein without
prior notification.
*WARNING

IntroductionNew Function
Sub Assemblies
Preventive Maintenance
Contents / Index
I. Introduction
1.1 Specification ..................................................................................... 1-1
1.2 Features............................................................................................ 1-3
1.3 System Configuration ....................................................................... 1-4
1.4 Operation .......................................................................................... 1-7
1.5 Component Location......................................................................... 1-8
1.6 Copy Process ................................................................................. 1-10
1.7 Precautions on Set Up .................................................................... 1-11
1.8 Precautions with Consumables ...................................................... 1-12
II. New Function
2.1 Image Control ( Quantum TM Technology ) ....................................... 2-1
2.2 Toner Density Control ....................................................................... 2-3
2.3 Trouble Avoidance Mechanism ........................................................ 2-5
2.4 ETPTM System - Evaluative Toner Processing ................................. 2-7
2.5 Re-try Control for Paper Misfeed ...................................................... 2-8
III. Sub Assemblies
3.1 Main Drive......................................................................................... 3-1
3.2 Operation
(1) Sheet bypass paper feed ....................................................... 3-2
(2) Paper feed unit....................................................................... 3-5
(3) Developer unit ........................................................................ 3-8
(4) Toner hopper unit................................................................. 3-14
(5) Paper transport unit and separation unit .............................. 3-17
(6) Fuser unit ............................................................................. 3-19
(7) Optics unit ............................................................................ 3-24
(8) Automatic duplex unit ( ADU ).............................................. 3-33
IV. Preventive Maintenance
4.1 Precautions for Periodic Maintenance Service ................................. 4-1
4.2 Cleaning Method............................................................................... 4-2
4.3 Disassembly and Re-assembly
(1) Multi-feed bypass ................................................................... 4-6
(2) Paper feed unit....................................................................... 4-9
(3) Developer unit ...................................................................... 4-12
(4) Fuser unit ............................................................................. 4-17
(5) Optics unit ............................................................................ 4-22
(6) Automatic duplex unit ( ADU ).............................................. 4-30
(7) Main Body ............................................................................ 4-33

Caution:
Danger of explosion if battery is incorrectly replaced.
Replace only with the same or equivalent type recommended by the manufacturer.
Dispose of used batteries according to the manufacture's instructions.

1-1
Introduction
Section I
Introduction
1. 1 Specifications
1.Type Desk Top
2.Copy process Electrostatic photographic method
3.Development process Two component magnetic brush
4.Maximum original size Ledger(11"x17") / A3(297 x 420mm)
5.Copy speed FP-7750 FP-7742
Ledger/A3 : 31 cpm 25 cpm
Legal/B4,FLS : 35 cpm 28 cpm
Letter-R/A4R : 41 cpm 35 cpm
Letter/A4 : 50 cpm 42 cpm
Invoice/A5 : 50 cpm 42 cpm
6.First copy time [FP-7750] 2.9 sec.(Letter/A4 size/Without Auto mode)
3.6 sec.(Letter/A4 size/With Auto mode)
[FP-7742] 3.0 sec.(Letter/A4 size/Without Auto mode)
3.8 sec.(Letter/A4 size/With Auto mode)
7.Copy ratio Enlargement(fixed) : 2.00, 1.55, 1.29, 1.21
Reduction (fixed) : 0.79, 0.77, 0.65, 0.61, 0.50
Zoom : 50%-200% (1%step)
8.Copy size Ledger/A3–Invoice/A5
9.Paper capacity Cassette : 550 sheets
Multi-feed bypass : 50 sheets
10.Paper feed Front loading universal paper cassette
Multi-feed bypass tray
11.Paper exit tray capacity 250 sheets
12.Paper weight Cassette : 16–24 lbs ( 60–90g/m2)
Bypass : 15–30 lbs(55–130g/m2)
13.Special paper OHP,Label paper, Tracing paper
(Through multi-feed bypass)
14.Continuous copying 1-999 reset to 1
15.Fusing system Heat and Pressure

1-2
16.Photoreceptor Organic Photo Conductor(OPC)
17.Exposure control 7 step digital+Photo/Auto button
18.Warm up time Approximately 270sec.(FP-7750)
Approximately 180sec.(FP-7742)
19.Power consumption Less than 1.5 kW
20.Power source AC120V 60Hz / AC220 - 240V 50Hz
21.Dimensions(W)(D)(H) 23.9" ×26.0" ×22.9" / 606 ×661 ×582 mm
22.Weight 161 lbs (FP-7742), 161.5 lbs (FP-7750) / 74kg
23.Ambient conditions Temperature : 50–86F/10–30 °C
Relative humidity : 30–80%
24.Optional accessories i-ADF FA-A888
ADF FA-A505
Sorter FA-S575(20bin sorter)
FA-S680(20bin staple sorter)
System console FA-DS82
LCC FA-MA301
* Specifications are subject to change without notice.

1-3
Introduction
1. 2 Features
• Introducing QuantumTM Technology copy density control
With QuantumTM Technology used for copy density control, optimum copies are
maintained for a long time in variable environmental conditions.
• User friendly operation
The touch panel enables simple operation.
• Enhancements in serviceability
If trouble happens, the self diagnosis mechanism illustrates the area for easy
service.
• Standard Automatic Duplexing(FP-7742/7750)
An Automatic Duplex Unit is provided standard, in addition to front paper loading
(550 sheets) + Multiple sheet bypass (50 sheets).
• Functional expansion through optional accessories
Equipping with the system stand and LCC allows a high copy volume
(maximum feed paper capacity 5250 sheets: four drawers + LCC + multiple sheet
bypass).
ADF and sorter can be connected with the main system easily by using exterior
connectors.
• Environmental considerations
We remember the environment by reducing machine noise for quieter offices,
designing for lower power consumption, and the ETPTM System(-Evaluative Toner
Processing System), utilizing toner recycling and increased plastic recycleables.

1-4
1. 3 FP-7742/7750 System Configuration
FP-7742/7750 Main Unit & Accessories
Main Unit FP-7742/7750
i-ADF FA-A888
ADF FA-A505
System console FA-DS82
Paper drawer FA-MA055
LCC FA-MA301
20 bin sorter FA-S575
20 bin staple sorter FA-S680
Consumables
Toner FQ-TK20
Developer FQ-ZK20
Drum FQ-HK20
i-ADFADF
FP-7742/7750
50
ADU
550
Sorter
20 bin/ 20 bin staple Paper drawer
550
System console
550
Cover
Storage
LCC
3000

1-5
Introduction
<Commonality of accessories>
Accessories FP-7718 FP-7722 FP-7728 FP-7735 FP-7742 FP-7750
FA-DS72 \\\\✕✕
FA-DS82 ✕✕✕✕\\
LCC ( FA-MA301 ) ✕✕\\\\
Number of drawer 1 2 2 2 1 + ADU 1 + ADU
Auto Duplex unit ✕Option Option Option Standard Standard
ADF \\\\\\
i-ADF ✕✕\\\\
10bin sorter \\\✕✕✕
10bin staple sorter \\\✕✕✕
20bin sorter ✕\\\\\
20bin staple sorter ✕\\\\\
ADF
Copier
paper feed
System
console
Sorter
Key: \ = OK ✕= N/A
System Console FA-DS72: Storage tray,Cover ×1
( 2 drawers drive mechanism )
FA-DS82: 550 sheets paper drawer, Storage tray, Cover
( 3 drawers drive mechanism )

1-6
Department counter 50 50 100 100 100 100
Cover, Interleaving, Presentation No No No No Yes Yes
Job memory 222255
This Service Manual is based on the FP-7742/7750.
To identify areas where the other models differ, please refer to this chart and the
Field Service Manual for each model.
FP-7718 FP-7722 FP-7728 FP-7735 FP-7742 FP-7750
Warm up time ( sec.) 40 50 70 70 180 270
First copy time ( sec.) 4.8 4.0 4.0 4.0 3.2 2.9
Paper feed cassette 1222 1+ADU 1+ADU
System stand DS72 DS72 DS72 DS72 DS82 DS82
Copy speed 18 22 28 35 42 50
Control panel design LED LED LCD display LCD display LCD touch panel LCD touch panel
Transfer corona cleaner No No No No Yes Yes
Drum separation finger No No No No Yes Yes
Fuser lamp 111122
Process speed ( mm/sec. ) 170 210 210 210 300 340
Developer suction No No No No Yes Yes
Fresh toner recycling No No Yes Yes Yes Yes
Toner bottle life 10K 10K 20K 20K 20K 20K
Waste toner bottle capacity 10K 10K 120K 120K 120K 120K
PM cycle 80K 80K 120K 120K 120K 120K
[ Comparison of specifications ]

1-7
Introduction
21 5
8
3
6
90
4
7
1. 4 Operation
Energy Saver Interrupt Key
User Preset Key Touch Panel Display Manual Key
Clear/Stop Key
Press to stop copy run
or clear copy count in
display.
Print Key
Reset Key
Press to reset all
features to initial
power-on state.
Original Size
Keys
Multi Size
Key
Job Memory Key Copy Size Keys
Quantity Keys Ready Indicator
Ready: Green LED
Not ready: Red LED
Copy Reservation: Flashing

1-8
1. 5 Component Location
( Outer view )
Paper feed cover
Bypass
Front cover
Paper drawer/tray
ADU (Automatic duplex unit)
Paper exit
cover
Control panel
Power switch

1-9
Introduction
( Inner view )
1 Half-speed unit
2 Full-speed unit
3 Lens Position sensor
4 Thermistor
5 AE Sensor
6 Main motor
7 Lens unit
8 Charge corona
9 No.6 mirror
10 Slit glass
11 No.4 mirror
12 No.5 mirror
13 LED array
14 Magnetic roller
15 Registration roller
16 Bypass pick-up roller
17 Bypass paper feed roller
18 Bypass DFP roller
19 Middle roller
20 Paper feed roller
21 DFP roller
22 Pick-up roller
23 ADU Paper feed roller
24 Corona cleaner
25 Transfer/Separation corona
26 Drum
27 Transfer belt
28 Pressure roller
29 Fuser lamps
30 Fuser separation finger (lower)
31 Reverse roller
32 Fuser separation finger (upper)
33 Paper exit roller
34 Paper exit sensor
35 Heat roller
36 Cleaning Web roller
37 Full-speed unit home postion sensor
38 Drum separation finger
234567
38 8 9 10 11 12
13
14
15
16
17
18
19
20
21
222324252627
28
29
30
31
32
33
34
35
36
37
1

1-10
1. 6 Copy Process
Charger
Discharge lamp
Cleaning
Fusing
Exit
ADU
Paper feed
Separation Transfer
Developer Toner
Exposure Original
Reduction Discharge
Trimming
–DC
Discharge lamp:
Transfer/Separation Fusing: Cleaning:
Primary Charge: Image Exposure: Developing:
Drum surface
approximately 800V
Charge corona
Drum
Latent
charge
image
Illumination
Magnetic
roller
Bias: –250 V
Latent charge
image(–)
Discharge
lamp
Heat roller Fuser lamp
Paper
Pressure
roller
Latent image
Transfer
corona
Cleaning
blade Drum
Blacking prevention
Toner (+)
Toner
Paper
Separation
corona

1-11
Introduction
1. 7 Precautions on Set Up
Copy machine performance and the copy quality is subject to and dependant
on environmental conditions. To maintain good performance, quality, and safe
operation, observe the following precautions:
1) Do not install the system under the following conditions to operate safely and
avoid trouble.
• High temperature, high humidity, low temperature or low humidity
• The temperature or humidity varies suddenly
• Being exposed to direct sunlight
• Dusty space
• Badly ventilated location
• Exposed to chemical gases (such as ammonia gas)
• Exposed to strong vibration
• Directly exposed to direct wind (ex. outlet of air conditioner)
2) The weight of machine is 220lb(100 kg) or more with options. It must be placed
on a firm platform which is level.
3) The maximum power consumption is 1.5 kW. Use an independent power supply
of 120 V and 15 A (220-240V and 7A)or higher. (Do not use a extension cord.)
4) Make sure the machine is properly grounded. (Do not ground to gas or water
pipe.)
• A ground terminal is provided on the back of the copier main body.
• Strip the end of a ground wire and connect with a ground terminal.
5) Install the machine with enough space around it.
4"/100 mm
14"/350mm 28"/700mm
Copier Multi sheet bypassExit tray

1-12
1. 8 Precautions with Consumables
(1) Photoreceptor drum
• Do not touch the surface (with the hand or any thing else).
• Stand the drum with the drum gear up for storage.
• Be careful not to smear with saliva, water, oil and so on.
• Do not place a where the temperature is high.
• Do not place it in strong light (such as direct sunshine or at window).
• Do not expose it to chemical gas or vapor.
• Do not store the developer unit with the photo receptor drum installed without
covering it with clean paper.
(2) Toner Developer
1) Do not mix different types of toner and developer.
• The machines are designed to use exclusive toner and developer for specific
models. Do not mix with toner and developer for other models.
2) Do not mix foreign materials.
Be careful not to include foreign materials in the toner and developer. If you
spilled toner or developer on a table or floor when adding toner or developer in
the developer unit, discard what was dropped. Such supplies may damage
the drum as well as cause other trouble with the image.
3) Do not place into other containers.
Toner and developer must not be placed into other containers, because some
containers may change the characteristics of the supply. Vinyl chloride
potentially changes the characteristics of supplies because of migrating
plasticizers.
4) Precautions on storage and transport
• Toner and developer additives are sensitive to temperature (high temperature
in particular) and humidity (high humidity in particular). Pay attention to the
following items for storage and transport.
• Store them in a dark and cool location (lower than 95 F/35 C) and out of direct
sunshine.
• Be careful not to expose them to rain or direct sunshine during transportation.
When delivered by truck the temperature inside must be not higher than 104
F/40 C.(Under the sun in summer, the inside temperature can typically be
140 F/60 deg.C or higher in a closed vehicle compartment.)

1-13
Introduction
• There are normally no special problems with storage and transport in a cold
climate but, store in a low humidity condition. Do not put supplies near heaters.
5) Safety and hygiene
Toner has the property of easily being wind blown. Toner on skin does not
cause any damage to health but, inhaling it is undesirable even if a powder is
simply dust. Therefore, be careful not to inhale toner .
• Handle the toner gently when changing cartridges, and developer when pouring
in the developer unit. If you have breathed in a lot of toner by mistake, rinse
out your mouth with water completely. Any toner on the skin should be washed
off with soapy water.
• Toner stuck on clothing must be removed in a dry condition (by a vacuum
cleaner, brush, or beating,) and then washed with soapy water. Wiping off with
benzine, alcohol, or thinner is not recommended because it may partially melt
the components of toner even more, resulting in a harder stain and spot.
• Toner spilled must be cleaned with a vacuum cleaner, and then wiped with a
cloth dampened with a neutral detergent and wrung out.
• If exposed to flames toner and developer will burn. Keep these supplies away
from open flames.
• Any wasted consumables (photo receptor, developer and toner) should be
recycled.
• Wear rubber gloves, eye protection and so on before handling any solvents
such as IPA.

New Function
2-1
Section II
New Function
2. 1 Image Control (Quantum TM Technology)
• Even if the toner density is at it's standard level, the copy image may vary with
time depending on the characteristics of drum and the environmental variations.
To prevent this change, the copy density sensor which is installed under the
developer unit controls the image to stablize the copy image.
• Controlling the image
During initialization after turning on the power, the copy density sensor reads the
white density, medium density (line pattern density patch) and black density
developed on the drum surface.These three values are compared with the ideal
gamma curve stored in the copiers memory.
The copier detects the amount offset from the standard gamma curve (such as "a
little background" or "light image") and calculates the variables for copy density
control in accordance with Quantum TMTechnology. In this way it finds the optimum
compensation values to tighten the gamma curve for maintaining peak copy quality.
By means of this process, copy quality is stabilized by the various compensations
enabled by Quantum adjustment in image production.
• The control of the gamma curve stabilizes copy quality by monitoring three points
of copy quality (white density, medium density and black density) and has a direct
effection on background, solid area density and good reproduction of fine lines
regardless of environmental changes and variation with time and copy volume.
• Quantum TM Technology
Quantum TM Technology is adaptive control on the basis of quantative reasoning
theory. While successively reasoning and learning the change of process
characteristics regardless of environmental changes and the variations with time
and the number of copies on the copier, the system reads the patch marks and
determines the best values of exposure and surface potential to establish the
best gamma curve for optimum copy quality.

2-2
• Quantum TM Technology is applied at the following intervals.
a) During initialization after turning on the power.
b) After every 1,000 sheets following execution of Quantum TM Technology
(But, every 200 sheets following the execution of F8-09 for the next
500 sheets)
c) After turning on the power (up to 200 copies)
d) After replacing the toner bottle (up to 200 copies)
• Copy density detecting sensor
Two sensors for detection of copy density are used, one for white density, and
line pattern density and one for detection of black density. (Temperature and
humidity sensors are not used.)
• To correct for toner build up on the sensor, clean the sensor at the same time as
the replacement of the drum. The system provides a measured amount of light
and detects the reflected light. The resultant value is used for sensor compensation.
This becomes the reference value.
• As the reference value of the white density changes, various components are
adjusted according to characteristics of the gamma curve.
Reference F5-25: Quantum Technology Operation ON/OFF
F mode F6-80: Automatic compensation value (read only)
F6-81: Automatic compensation value (read only)
F6-82: Automatic compensation value (read only)
F6-28: White density reference value
(set by Quantum)
F6-29: Black density reference value
(set by Quantum)

New Function
2-3
Amount of carrier passing TDC sensor Toner density condition Sensor output voltage
Less High Lower than normal
Much Low Higher than normal
<Control>
The following controls are necessary for normal control of toner density
1) Automatic adjustment of TDC sensor gain (during execution of F8-C09)
(to attain the standard reference level).
2) Maintain the standard level by control of toner density during use.
<Explanation of the control system>
1) Automatic adjustment of TDC sensor gain
Automatically adjust the reference through the TDC sensor by executing service
mode F8-09.
The operation flow is as shown below.
2. 2 Toner Density Control
To keep toner density(toner carrier ratio) in the developer unit constant, the TDC
sensor (toner density sensor) which is installed under the developer unit detects the
amount of carrier in the developer unit to control the toner density.
<Fundamentals>
The change of magnetic flux density in accordance with the amount of carrier
(magnetic power) of the developer (mixture of toner and carrier) is detected by the
TDC sensor and is converted to a voltage to control the toner density.
<Change of toner density and change of TDC sensor output voltage>
F8-09 start
CPU will check toner density sensor output. (2.5 V)
CPU will adjust sensor gain
control signal
Memory number will be changed to new number in memory.
(F6-21 or F6-26)
Toner density sensor output voltage will be adjusted to 2.5 V
Yes No