Home » Brother International Manuals » Multifunction Devices » Brother International MFC 8500 » Manual Viewer

Brother International MFC 8500 Service Manual - Page 36

Sensors and Actuators, Toner sensor LED PCB

UPC - 012502603832

View all Brother International MFC 8500 manuals

Add to My Manuals
Save this manual to your list of manuals

Page 36 highlights

2.3 Sensors and Actuators This machine has 12 sensors: nine photosensors, two thermistors and a mechanical switch as described below. Sensor name Document front sensor Document rear sensor Manual insertion sensor Registration sensor Cassette sensor Paper ejection sensor Toner sensor Cover sensor Jam sensor Heater thermistor In-casing temperature sensor Hook switch* Type Photosensor Photosensor Photosensor Photosensor Photosensor Photosensor Photosensor Photosensor Photosensor Thermistor Thermistor Mechanical switch Located on Control panel PCB Document sensor PCB Control panel PCB ASSY Engine PCB Engine PCB Engine PCB Paper ejection sensor PCB Toner sensor (LED) PCB and toner sensor (light-receiver) PCB Toner sensor (LED) PCB Heat-fixing unit Heat-fixing unit Left-hand plate of the main chassis Hook switch PCB* *For models equipped with a handset • Document front sensor which detects the presence of documents. • Document rear sensor which detects the leading and trailing edges of pages to tell the control circuitry when the leading edge of a new page has reached the starting position and when the scan for that page is over. • Manual insertion sensor which detects whether paper is inserted manually through the paper slot or whether paper fed through the paper cassette has jammed. • Registration sensor which detects the leading and trailing edges of recording paper, which allows the controller to determine the registration timing and check paper jam. • Cassette sensor which detects whether the paper cassette is loaded. • Paper ejection sensor which detects whether the recording paper goes out of the equipment. • Toner sensor which detects whether there is toner or a toner cartridge is loaded. • Cover sensor which detects whether the front cover is closed. • Jam sensor which detects whether paper is jammed inside the heat-fixing unit. • Heater thermistor which allows the controller to monitor the temperature of the heater roller of the fixing unit. • In-casing temperature sensor which allows the controller to monitor the temperature inside the equipment. • Hook switch* which detects whether the handset is placed on the handset mount*. The above photosensors are a photointerrupter consisting of a light-emitting diode and a light-sensitive transistor. Each of them has an actuator separately arranged as shown on the next page. III - 10

Section	Page
CHAPTER I. GENERAL DESCRIPTION	6
1. EQUIPMENT OUTLINE	7
1.1 External Appearance and Weight	7
1.2 Components	7
2. SPECIFICATIONS	8
CHAPTER II. INSTALLATION	21
1. INSTALLING THE UPDATE DATA TO THE FACSIMILE MACHINE	22
2. SETTING ID CODES TO FACSIMILE MACHINES	24
CHAPTER III. THEORY OF OPERATION	26
1. OVERVIEW	27
2. MECHANISMS	28
2.1 Scanner Mechanism	29
2.1.1 Document feeding and ejecting mechanism	29
2.1.2 Scanner	29
2.2 Laser Printing Mechanism	30
2.2.1 Paper pick-up and registration mechanism	30
2.2.2 Print process mechanism	31
(1) Charging process	32
(2) Exposing process	32
(3) Developing process	33
(4) Transferring process	33
2.2.3 Heat-fixing mechanism	34
2.2.4 Paper ejecting mechanism	35
2.3 Sensors and Actuators	36
3. CONTROL ELECTRONICS	38
CHAPTER IV. DISASSEMBLY/REASSEMBLY AND LUBRICATION	40
1. DISASSEMBLY/REASSEMBLY	42
Safety Precautions	42
Preparation	43
How to Access the Object Component	43
Disassembly Order Flow	44
1.1 Rear Cover	45
1.2 Access Plates R and F	45
1.3 Control Panel ASSY	46
1.4 Panel Rear Cover and Control Panel	47
1.5 Document Feed Roller ASSY, Document Ejection Roller ASSY, and Pinch Rollers	50
1.6 CIS Unit	51
1.7 Scanner Frame ASSY (Scanner Motor, Scanner Drive Unit, Document Take-in Roller,	52
1.8 Top Cover (Exit Roller, Speaker, and Document Guides)	56
1.9 Handset Mount and Hook Switch PCB (for models equipped with a handset)	62
1.10 Paper Sub Tray	64
1.11 VC Cover, VC Bracket, and VC Connector PCB (for models supporting video capture)	65
1.12 Front Cover	66
1.13 Outer Chute and Paper Pinch Rollers	67
1.14 Main Cover	68
1.15 Switch Cover	69
1.16 Laser Unit	70
1.17 Heat-fixing Unit and FU Lamp	71
[Disassembling the heat-fixing unit]	73
1.18 Fan	85
1.19 Drive Gear ASSY and Main Motor ASSY	87
1.20 NCU Shield and NCU PCB	89
1.21 Bottom Plate, Main PCB, and Bottom Insulation Film	91
1.22 Low-voltage Power Supply PCB and Power Inlet	95
1.23 Inner Insulation Film, High-voltage Power Supply PCB, Engine PCB, and 2nd Cassette Relay PCB*	97
1.24 Toner Sensor (light-receiver) PCB and Toner Sensor (LED) PCB	99
1.25 Gears and Paper Pick-up Roller	100
1.26 Paper Feed Roller ASSY	101
1.27 Clutch Levers, Cassette Guide L, and Solenoid	102
1.28 Paper Cassette	103
1.29 Cleaning of High-voltage Contacts and Grounding Contacts	104
2. LUBRICATION	106
[ 1 ] Document feed roller ASSY and document ejection roller ASSY	106
[ 2 ] Control panel locks	107
[ 3 ] Scanner frame ASSY, document take-in roller and its shaft, and separation roller and its shaft	107
[ 4 ] Top cover	108
[ 5 ] Drive gear ASSY	109
[ 6 ] Paper cassette	110
CHAPTER V. MAINTENANCE MODE	112
1. ENTRY INTO THE MAINTENANCE MODE	113
2. LIST OF MAINTENANCE-MODE FUNCTIONS	114
3. DETAILED DESCRIPTION OF MAINTENANCE-MODE FUNCTIONS	116
3.1 EEPROM Parameter Initialization	116
3.2 Printout of Scanning Compensation Data	117
3.3 ADF Performance Test	119
3.4 Test Pattern 1	120
3.5 Firmware Switch Setting and Printout	121
[ A ] Firmware switch setting	121
[ B ] Printout of firmware switch data	123
3.6 Operational Check of LCD	124
3.7 Operational Check of Control Panel PCB	124
3.8 Receiver Volume Adjustment (applicable to the American version only)	126
3.9 Sensor Operational Check	127
3.10 Fine Adjustment of Scanning Start/End Position	128
3.11 CIS Scanner Area Setting	129
3.12 EEPROM Customizing	129
3.13 Display of the Equipment's Log Information	130
3.14 Equipment Error Code Indication	131
3.15 Output of Transmission Log to the Telephone Line	131
3.16 Cancellation of the Memory Security Mode (applicable to the European version only)	132
CHAPTER VI. ERROR INDICATION AND TROUBLESHOOTING	134
1. ERROR INDICATION	135
1.1 Equipment Errors	135
[ 1 ] Error messages on the LCD	135
[ 2 ] Error codes shown in the \	139
1.2 Communications Errors	141
2. TROUBLESHOOTING	151
2.1 Introduction	151
2.2 Precautions	151
2.3 Checking prior to Troubleshooting	151
2.4 Troubleshooting Procedures	153
[ 1 ] Control panel related	153
[ 2 ] Telephone related	153
[ 3 ] Communications related	154
[ 4 ] Paper/document feeding related	154
[ 5 ] Print-image related	155
Location of High-voltage Contacts and Grounding Contacts	162
Appendix 1. EEPROM Customizing Codes	164
Appendix 2. Firmware Switches (WSW)	167
Appendix 3. Circuit Diagrams	215
A. Main PCB (MFC8500)	216
B. Main PCB (MFC9660)	226
C. Engine PCB	227
D. NCU PCB	228
E. Control Panel PCB	232

Match case Limit results 1 per page

III

- 10

2.3

Sensors and Actuators

This machine has 12 sensors: nine photosensors, two thermistors and a mechanical switch as

described below.

Sensor name

Type

Located on

Document front sensor

Photosensor

Control panel PCB

Document rear sensor

Photosensor

Document sensor PCB

Manual insertion sensor

Photosensor

Engine PCB

Registration sensor

Photosensor

Engine PCB

Cassette sensor

Photosensor

Engine PCB

Paper ejection sensor

Photosensor

Paper ejection sensor PCB

Toner sensor

Photosensor

Toner sensor (LED) PCB and toner

sensor (light-receiver) PCB

Cover sensor

Photosensor

Toner sensor (LED) PCB

Jam sensor

Photosensor

Heat-fixing unit

Heater thermistor

Thermistor

Heat-fixing unit

In-casing temperature sensor

Thermistor

Left-hand plate of the main chassis

Hook switch*

Mechanical switch

Hook switch PCB*

*For models equipped with a handset

•

Document front sensor which detects the presence of documents.

•

Document rear sensor which detects the leading and trailing edges of pages to tell the control

circuitry when the leading edge of a new page has reached the starting position and when the

scan for that page is over.

•

Manual insertion sensor which detects whether paper is inserted manually through the paper slot

or whether paper fed through the paper cassette has jammed.

•

Registration sensor which detects the leading and trailing edges of recording paper, which

allows the controller to determine the registration timing and check paper jam.

•

Cassette sensor which detects whether the paper cassette is loaded.

•

Paper ejection sensor which detects whether the recording paper goes out of the equipment.

•

Toner sensor which detects whether there is toner or a toner cartridge is loaded.

•

Cover sensor which detects whether the front cover is closed.

•

Jam sensor which detects whether paper is jammed inside the heat-fixing unit.

•

Heater thermistor which allows the controller to monitor the temperature of the heater roller of

the fixing unit.

•

In-casing temperature sensor which allows the controller to monitor the temperature inside the

equipment.

•

Hook switch* which detects whether the handset is placed on the handset mount*.

The above photosensors are a photo-

interrupter consisting of a light-emitting diode

and a light-sensitive transistor.

Each of

them has an actuator separately arranged as

shown on the next page.

Control panel

PCB ASSY