Samsung ML-4550 Service Manual

DIGITAL LASER PRINT CONTENTS

[The keynote of Product]

- Series Model: ML-4550 / 4551N / 4551ND

- High speed Laser Printer: Up to 43 ppm in A4 (45 ppm in Letter), Duplex: 29 ipm (A4); 30 ipm (Letter)

- Resolution: Up to 1200 x 1200 dpi

- Marvell 500Mhz

- Memory: 128 MB (Max. 512 MB) 128, or 256 MB optional memory available. Use only the Samsung-approved DIMM. 128 MB: ML-MEM150, 256 MB: ML-MEM160

- Option: ML-4550:500-sheet trays, ethernet 10/100 Base TX wired LAN, ethernet 10/100 Base hard disk, duplex unit, DIMM

- Toner cartridge:

Starter: 10K or 20K pages Consumable: 10K or 20K pages

- Duty cycle: Monthly Up to 150,000 pages

Manual

SERVICE

Basic Model :ML-4550

ML-4551N/XAZ

1. Precautions

1.1 Safety Warning 1-1

1.2 Caution for safety

1-2

1.3 ESD Precautions

1-5

2. Product spec and feature

2.1 Product Specifications 2-1

2.1.1 Product Overview 2-1

2.1.2 Specifications

2-1

2.1.3 Model Comparison Table

2-6

2.2 Summary of Product

2-1

2.2.1 Printer Components

2-7

2.2.2 System Layout

2-13

2.2.3 Engine H/W Specifications

2-17

3. Disassembly and Reassembly

3.1 General Precautions on Disassembly 3-1

3.2 Transfer Roller

3-2

3.3 MPF Ass’y

3-3

3.4 Holder Pad Ass'y

3-4

3.5 Retard Ass'y

3-5

3.6 Feed2 Idle Unit

3-6

3.7 Cover Right

3-7

3.8 Main PBA

3-8

3.9 Main Drive Ass'y

3-9

3.10 DEVE Drive Ass'y

3-10

3.11 Connector PBA

3-11

3.12 Solenoid

3-12

Contents

3.13 Rear Cover 3-13

3.14 Cover Left

3-14

3.15 Top Cover

3-15

3.16 Open Cover

3-16

3.17 Inner Cover

3-17

3.18 Fuser Ass'y

3-18

3.19 Duplex Solenoid Ass'y

3-20

3.20 Exit Roller

3-21

3.21 LSU

3-22

3.22 DC Fan

3-23

3.23 Toner Sensor PBA

3-24

3.24 REGI Ass'y

3-25

3.25 MP Pick Up Ass'y

3-26

3.26 Pick Up & Feed2 Assy

3-28

3.27 Engine Shield

3-31

4. Alignment & Troubleshooting

4.1 Alignment and Adjustments 4-1

4.1.1 How to use EDC (Engine Diagnostic Control) Mode 4-1

4.1.2 Paper Path

4-10

4.1.3 Sample Pattern

4-17

4.1.4 Periodic Defective Image

4-18

4.1.5 Error Messages

4-19

4.2 Troubleshooting 4-22

4.2.1 Procedure of Checking the Symptoms

4-22

4.2.2 The cause and solution of Bad image 4-23

4.2.3 The cause and solution of the bad discharge

4-39

4.2.4 The cause and solution of the malfunction

4-49

4.2.5 Maintaining the toner cartridge

4-59

4.2.6

The cause and solutions of bad environment of the software

4-65

Continued

5. Exploded Views & Parts List

5.1 Main Assembly 5-2

5.2 Cover Assembly

5-5

5.3 Frame Assembly

5-8

5.4 Fuser Unit

5-14

5.5 REGI Assembly

5-16

5.6 Main Motor Assembly

5-18

5.7 Deve Motor Assembly

5-20

5.8 Exit Sorenoid Assembly

5-22

5.9 Cassette Assembly

5-24

5.10 Duplex Unit

5-26

5.11 SCF Unit

5-28

6. System Diagram

6.1 Block Diagram 6-1

6.2 SCX-4200 Connection Diagram

6-3

7. Reference Information

7.1 Troubleshooting Tools 7-1

7.2 Acronyms and Abbreviations

7-2

7.3 Select a location for the printer

7-4

7.4 Sample Tests Patterns

7-5

Continued

Precautions

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Service Manual

1-1

1. Precautions

In order to prevent accidents and to prevent damage to the equipment please read the precautions listed below carefully before servicing the printer and follow them closely.

1.1 Safety Warning

(1) Only to be serviced by appropriately qualified service engineers.

High voltages and lasers inside this product are dangerous. This printer should only be serviced by a suitably trained and qualified service engineer.

(2) Use only Samsung replacement parts

There are no user serviceable parts inside the printer. Do not make any unauthorized changes or additions to the printer, these could cause the printer to malfunction and create electric shock or fire hazards.

(3) Laser Safety Statement

The Printer is certified in the U.S. to conform to the requirements of DHHS 21 CFR, chapter 1 Subchapter J for Class 1(1) laser products, and elsewhere, it is certified as a Class I laser product conforming to the requirements of IEC 825. Class I laser products are not considered to be hazardous. The laser system and printer are designed so there is never any human access to laser radiation above a Class I level during normal operation, user maintenance, or prescribed service condition.

Warning >> Never operate or service the printer with the protective cover removed from Laser/Scanner assembly. The

reflected beam, although invisible, can damage your eyes. When using this product, these basic safety pre-cautions should always be followed to reduce risk of fire, electric shock, and injury to persons.

CAUTION - INVISIBLE LASER RADIATION 

WHEN THIS COVER OPEN.  DO NOT OPEN THIS COVER.

VORSICHT - UNSICHTBARE LASERSTRAHLUNG, 

WENN ABDECKUNG GEÖFFNET.  NICHT DEM STRAHL AUSSETZEN.

ATTENTION - RAYONNEMENT LASER INVISIBLE EN CAS 

D’OUVERTURE. EXPOSITION DANGEREUSE  AU FAISCEAU.

ATTENZIONE - RADIAZIONE LASER INVISIBILE IN CASO DI 

APERTURA. EVITARE L’ESPOSIZIONE AL  FASCIO.

PRECAUCION - RADIACION LASER IVISIBLE CUANDO SE ABRE. 

EVITAR EXPONERSE AL RAYO.

ADVARSEL. - USYNLIG LASERSTRÅLNING VED ÅBNING, NÅR 

SIKKERHEDSBRYDERE ER UDE AF FUNKTION.  UNDGÅ UDSAETTELSE FOR STRÅLNING.

ADVARSEL. - USYNLIG LASERSTRÅLNING NÅR DEKSEL 

ÅPNES. STIRR IKKE INN I STRÅLEN.  UNNGÅ EKSPONERING FOR STRÅLEN.

VARNING - OSYNLIG LASERSTRÅLNING NÄR DENNA DEL 

ÄR ÖPPNAD OCH SPÄRREN ÄR URKOPPLAD.  BETRAKTA EJ STRÅLEN. STRÅLEN ÄR FARLIG.

VARO! - AVATTAESSA JA SUOJALUKITUS OHITETTAESSA 

OLET ALTTIINA NÄKYMÄTTÖMÄLLE LASER- SÄTEILYLLE ÄLÄ KATSO SÄTEESEEN.

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Service Manual

Precautions

1-2

1.2 Caution for safety

1.2.1 Toxic material

This product contains toxic materials that could cause illness if ingested.

(1) If the LCD control panel is damaged it is possible for the liquid inside to leak. This liquid is toxic. Contact with the skin

should be avoided, wash any splashes from eyes or skin immediately and contact your doctor. If the liquid gets into the mouth or is swallowed see a doctor immediately.

(2) Please keep toner cartridges away from children. The toner powder contained in the toner cartridge may be harmful

and if swallowed you should contact a doctor.

1.2.2 Electric Shock and Fire Safety Precautions

Failure to follow the following instructions could cause electric shock or potentially cause a fire.

(1) Use only the correct voltage, failure to do so could damage the printer and potentially cause a fire or electric

shock.

(2) Use only the power cable supplied with the printer. Use of an incorrectly specified cable could cause the cable

to overheat and potentially cause a fire.

(3) Do not overload the power socket, this could lead to overheating of the cables inside the wall and could lead to

a fire.

(4) Do not allow water or other liquids to spill into the printer, this can cause electric shock. Do not allow paper

clips, pins or other foreign objects to fall into the printer these could cause a short circuit leading to an electric shock or fire hazard..

(5) Never touch the plugs on either end of the power cable with wet hands, this can cause electric shock. When

servicing the printer remove the power plug from the wall socket.

(6) Use caution when inserting or removing the power connector. The power connector must be inserted com-

pletely otherwise a poor contact could cause overheating possibly leading to a fire. When removing the power connector grip it firmly and pull.

(7) Take care of the power cable. Do not allow it to become twisted, bent sharply round corners or other wise

damaged. Do not place objects on top of the power cable. If the power cable is damaged it could overheat and cause a fire or exposed cables could cause an electric shock. Replace a damaged power cable immediately, do not reuse or repair the damaged cable. Some chemicals can attack the coating on the power cable, weakening the cover or exposing cables causing fire and shock risks.

(8) Ensure that the power sockets and plugs are not cracked or broken in any way. Any such defects should be

repaired immediately. Take care not to cut or damage the power cable or plugs when moving the machine.

(9) Use caution during thunder or lightening storms. Samsung recommends that this machine be disconnected

from the power source when such weather conditions are expected. Do not touch the machine or the power cord if it is still connected to the wall socket in these weather conditions.

(10) Avoid damp or dusty areas, install the printer in a clean well ventilated location. Do not position the machine

near a humidifier. Damp and dust build up inside the machine can lead to overheating and cause a fire.

(11) Do not position the printer in direct sunlight. This will cause the temperature inside the printer to rise possibly

leading to the printer failing to work properly and in extreme conditions could lead to a fire.

(12) Do not insert any metal objects into the machine through the ventilator fan or other part of the casing, it could

make contact with a high voltage conductor inside the machine and cause an electric shock.

Precautions

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Service Manual

1-3

1.2.3 Handling Precautions

The following instructions are for your own personal safety, to avoid injury and so as not to damage the printer

(1) Ensure the printer is installed on a level surface, capable of supporting its weight. Failure to do so could cause

the printer to tip or fall.

(2) The printer contains many rollers, gears and fans. Take great care to ensure that you do not catch your fingers,

hair or clothing in any of these rotating devices.

(3) Do not place any small metal objects, containers of water, chemicals or other liquids close to the printer which if

spilled could get into the machine and cause damage or a shock or fire hazard.

(4) Do not install the machine in areas with high dust or moisture levels, beside on open window or close to a

humidifier or heater. Damage could be caused to the printer in such areas.

(5) Do not place candles, burning cigarettes, etc on the printer, These could cause a fire.

1.2.4 Assembly / Disassembly Precautions

Replace parts carefully, always use Samsung parts. Take care to note the exact location of parts and also cable routing before dismantling any part of the machine. Ensure all parts and cables are replaced correctly. Please carry out the following procedures before dismantling the printer or replacing any parts.

(1) Check the contents of the machine memory and make a note of any user settings. These will be erased if the

mainboard or network card is replaced. (2) Ensure that power is disconnected before servicing or replacing any electrical parts. (3) Disconnect printer interface cables and power cables. (4) Only use approved spare parts. Ensure that part number, product name, any voltage, current or temperature

rating are correct. (5) When removing or re-fitting any parts do not use excessive force, especially when fitting screws into plastic. (6) Take care not to drop any small parts into the machine. (7) Handling of the OPC Drum

- The OPC Drum can be irreparably damaged if it exposed to light. Take care not to expose the OPC Drum either to direct sunlight or to fluorescent or incandescent room lighting. Exposure for as little as 5 mins can damage the surface’s photoconductive properties and will result in print quality degradation. Take extra care when servicing the printer. Remove the OPC Drum and store it in a black bag or other lightproof container. Take care when working with the covers(especially the top cover) open as light is admitted to the OPC area and can damage the OPC Drum.

- Take care not to scratch the green surface of OPC Drum Unit. If the green surface of the Drum Cartridge is scratched or touched the print quality will be compromised.

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Service Manual

Precautions

1-4

1.2.5 Disregarding this warning may cause bodily injury

(1) Be careful with the high temperature part.

The fuser unit works at a high temperature. Use caution when working on the printer. Wait for the fuser to cool down before disassembly.

(2) Do not put finger or hair into the rotating parts.

When operating a printer, do not put hand or hair into the rotating parts (Paper feeding entrance, motor, fan, etc.). If do, you can get harm.

(3) When you move the printer.

This printer weighs 22kg including toner cartridge and cassette. Use safe lifting and handling techniques. Use the lifting handles located on each side of the machine. Back injury could be caused if you do not lift carefully.

(4) Ensure the printer is installed safely.

The printer weighs 22Kg, ensure the printer is installed on a level surface, capable of supporting its weight. Failure to do so could cause the printer to tip or fall possibly causing personal injury or damaging the printer.

(5) Do not install the printer on a sloping or unstable surface. After installation, double check that the printer is stable.

Precautions

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Service Manual

1-5

1.3 ESD Precautions

Certain semiconductor devices can be easily damaged by static electricity. Such components are commonly called “Electrostatically Sensitive (ES) Devices”, or ESDs. Examples of typical ESDs are: integrated circuits, some field effect transistors, and semiconductor “chip” components.

The techniques outlined below should be followed to help reduce the incidence of component damage caused by static electricity.

Caution >>Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

1. Immediately before handling a semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, employ a commercially available wrist strap device, which should be removed for your personal safety reasons prior to applying power to the unit under test.

2. After removing an electrical assembly equipped with ESDs, place the assembly on a conductive surface, such as aluminum or copper foil, or conductive foam, to prevent electrostatic charge buildup in the vicinity of the assembly.

3. Use only a grounded tip soldering iron to solder or desolder ESDs.

4. Use only an “anti-static” solder removal device. Some solder removal devices not classified as “anti-static” can generate electrical charges sufficient to damage ESDs.

5. Do not use Freon-propelled chemicals. When sprayed, these can generate electrical charges sufficient to damage ESDs.

6. Do not remove a replacement ESD from its protective packaging until immediately before installing it. Most replacement ESDs are packaged with all leads shorted together by conductive foam, aluminum foil, or a comparable conductive material.

7. Immediately before removing the protective shorting material from the leads of a replacement ESD, touch the protective material to the chassis or circuit assembly into which the device will be installed.

8. Maintain continuous electrical contact between the ESD and the assembly into which it will be installed, until completely plugged or soldered into the circuit.

9. Minimize bodily motions when handling unpackaged replacement ESDs. Normal motions, such as the brushing together of clothing fabric and lifting one’s foot from a carpeted floor, can generate static electricity sufficient to damage an ESD.

Product spec and feature

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Service Manual

2-1

Item Descriptions Remark

Basic Model ML-4550 Series Model ML-4550, ML-4551N, ML-4551ND, ML-4551NDG(Kor.) Maket of Sailes Office user Laser printer. (Network for work Group) Specification

43ppm(Ltr. 45ppm), 500MHz Processor, 128MB Memory 10K(initial), 20K(sailes) USB(Hight Speed USB 2.0), Network Option,

ML-4551N, ML-4551ND(Network base) Face Down(250 sheets), Face Up(100 sheets)

2. Product specification and feature

2.1 Product Specifications

2.1.1 Product Overview

2.1.2 Specifications

Product Specifications are subject to without notice. See below for product specifications.

2.1.2.1 General Specifications

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Engine Speed Simplex Up to 43 ppm in A4 (45 ppm in Letter)

Duplex Option : 29 ipm in A4 (30 ipm in Letter) Warmup time - Less than 45 sec : Power-on boot FPOT From Ready Less than 8.5 sec

From Idle Less than 43.5 sec

From Coldboot

Less than 53.5 sec

Resolution - Up to 1200 x 1200 dpi effective output

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Product spec and feature

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2.1.2.2. Controller & S/W

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Processor Marvell 500Mhz Memory Std. 128 MB

Max. 512MB(256+256)

Printer Languages

- PostScript3, PCL6, IBM ProPrinter, EPSON, PDF Direct(only HDD installed) Fonts - 45 scalable, 1 bitmap, 136 PostScript 3 fonts, OCR Fonts Driver Default Driver PCL6 : Win 95/98/NT4.0/2000/Me/XP(32/64bits)/2003 Server(32/64bits)

PS : Linux & Mac

Supporting OS

Windows 95/98/NT4.0/2000/Me/XP(32/62bits)/2003 Server(32/62bits) Various Linux OS including Red Hat 8~9, Fedora Core 1~3, Mandrake 9.2~10.1

and SuSE 8.2~9.2 Mac OS 8.6~9.2/10.1~10.4

WHQL Windows 2000, XP, 2003 Server

Wired Network

Protocol N/A SPX/IPX, TCP/IP, SNMP, HTTP 1.1, AppleTalk Supporting OS

N/A Windows 98/ME/NT4.0/2000/XP(32/64bits)/2003

Server(32/64bits) Netware 4.x, 5.x, 6.x Mac OS 8.6~9.2, 10.1~10.4 Various Linux OS including Red Hat 8.0~9.2, Fedora Core 1~3, Mandrake 9.2~10.1

and SuSE 8.2~9.2 Wireless Protocol N/A Network

Supporting OS

N/A

Application RCP N/A

Status Monitor N/A Smart Panel YES (Include RCP and SM)

Network N/A

Management Interface Parallel - IEEE 1284 USB - High Speed USB 2.0 Wired Network

- Optional 10/100 Base TX

Wireless Network

- N/A User Interface LCD - 16 x 12 Character LCD LED - 2LED(Status LED, Save Button LED) Key - 8 Key: Menu , , OK (*) , , Back Toner Save , Demo , Stop

Product spec and feature

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Service Manual

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2.1.2.3. Paper Handling

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Standard - 500-sheet Cassette Tray, 100-sheet Multi Purpose Tray @75g/ Capacity

Max. Capacity - 2,100 sheets @75g/ Printing Max. Size 216 x 356 mm (8.5" x 14")

Min. Size 76 x 127 mm (3.0" x 5.0")(>105g) Multi-purpose tray Capacity - 100 sheets @75g/ Media sizes - A4, A5, A6, Letter, Legal, Oficio, Folio, Executive,ISO B5, JIS B5, 3"x5", Monarch,

No.10, DL, C5, C6 Media type - Transparencies, Envelopes, Labels, Card stock Media weight - 16~43 lb (60 to176g/ ) Sensing - Paper empty sensor Standard Cassette Tray Capacity - 500 sheets @ 75g/ Media sizes - A4, A5, Letter, Legal, Executive, Folio, Oficio, ISO B5, JIS B5 Media types - Plain Paper Media weight - 16~28lb (60 to 105g/ ) Sensing - Paper empty sensor, Paper Size Sensor Second Optional

Cassette Tray Capacity - 500 sheets @ 75g/

Media sizes - A4, A5, Letter, Legal, Executive, Folio, Oficio, ISO B5, JIS B5 Media types - Plain Paper Media weight - 16~28lb (60 to 105g/ ) Sensing - Paper empty sensor, Paper Size Sensor Third Optional

Cassette Tray Capacity - 500 sheets @ 75g/

Face-Up 100 sheets @ 75g/

Output Full sensing

- Paper full Sensor Optional Stacker Capacity Face-Down N/A Duplex - Optional Built-in Supporting Media sizes - A4, Letter, Legal, Folio, Oficio Media types - Plain Paper Media weight - 20~24lb (75~90g/ )

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Service Manual

Product spec and feature

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2.1.2.4. Consumables

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Toner Black Standard 10K pages @ ISO 19752 5% Coverage

High Yield 20K pages @ ISO 19752 5% Coverage Key Electronic key(CRUM) Life detect Toner remaining volume would be traced via software

Drum Yield Same as consumables

2.1.2.5. Reliability & Service

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Printing Volume

- 5,000 sheets / month

(SET AMPV) Max. Monthly - 150,000 sheets

Duty MPBF - 150,000 sheets MTTR - 20 min. SET Life Cycle - 500,000 sheets or 5 years (whichever comes first)

2.1.2.6. Environment

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Acoustic Noise

Printing Less than 57.0 dBA

Level(Sound Power/Pressure)

Standby Less than 35.0 dBA Sleep Back Ground Level

Power AVG. Less than 650W Consumption

Sleep/Power Off

Less than 13W

Dimension SET 396 x 453 x 353 mm (15.6" x 17.8" x 13.9") 396 x 501 x 353 mm (W x D x H) (15.6" x 19.7" x 13.9")

SET Packing 518 x 566 x 568 mm (External) CRU 314 x 242 x 138 mm Toner Packing

370 x 286 x 180 mm (External)

Weight SET 17.8kg(39.2 Ib) 19.1kg

Toner(10K) 10K : 1.85kg(4.08 Ibs), 20K : 2.06kg(4.54 Ibs) Gross 21.6kg(47.62 Ibs) 23.5kg(51.81 Ibs)

Product spec and feature

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Service Manual

2-5

2.1.2.7. Options

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Memory - 128MB/512MB (256MB+256MB) Second Cassette

- 500 sheet Cassette Tray Third Cassette - 500 sheet Cassette Tray Stacker - N/A Stapler N/A PostScript - Default Wired Network

- Ethernet 10/100 Base Default Default

TX (Internal) Hard Disk - 40GB Duplex Unit - Optional Default

2.1.2.8. Others

ITEM ML-4550 SERIES

ML-4550 ML-4551N ML-4551ND

Performance Jam Rate Base Line Paper : 1/12K Requirement

Standard Paper : 1/10K

Stress Paper : 1/1500

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2.1.3 Model Comparison Table

Project SEC HP Lexmark Brother Dell

Model Name ML-4550 LJ-4250 T642 HL-8050N W5200N

Engine

FPOT 8.5 sec 8 sec 8.5 sec 9 sec 8.5 sec Speed(ppm) 43ppm (Ltr. 45ppm) 43ppm (Ltr. 45ppm) 43ppm (Ltr. 45ppm) 34ppm (Ltr. 35ppm) 43ppm (Ltr. 45ppm) Resolution 1200 dpi 1200 dpi 1200 dpi x 1200 dpi 1200dpi x 1200 dpi 1200 dpi x 1200 dpi Noise(dB)

57dB(Printing), 35dB(Idle)

not_inform

55dB(Printing), 30dB(Idle) 54dB(Printing), 27dB(Idle) 55dB(Printing),

34dB(Idle) Weight 17.83kg 20.2kg (45 lbs) 23.1Kg (51lbs) 20.6Kg (45.2 lbs) 45lbs Demension(W*D*H) 15.6 x 17.8 x 13.9 16.5 x17.8 x14.8 436x523x406mm 16.6 x 18.3 x 15.9 (17.2 x20.2 x16 )

396 x 453 x 353 mm 418x451x377mm (17.2

x20.6 x16 )

Control

Processor 500MHz 460MHz 457 MHz RISC 300MHz 500 MHz RISC Ram(Std.) 128MB 48MB 64MB 64MB 80MB Ram(Max.) 512MB 512MB 576MB 576MB 336MB Emulation PCL6, PS3 PCL6, PS3 PCL6, PS3 PCL6, PS3, PCL6, PS3,

10/100 Base TX 10/100 Base TX

Interface IEEE1284, USB 2.0 IEEE1284, USB 2.0 IEEE1284, USB 1.1 IEEE1284, USB IEEE1284, USB

2.010/100 Base TX 2.010/100 Base TX

Optional Interface 10/100 Base TX 10/100 Base TX 10/100 Base TX N/A N/A

Paper Handling

Paper Input(Capa./Type)

500 Sheets 500 Sheets 500 Sheets 550 Sheets Cassette 500 Sheets Cassette100 MP Tray Cassette100 MP Tray Cassette100 MP Tray 150 Sheets Cassette Cassette100 MP Tray

Paper Output 250 Sheets Face down 250 Sheets Face down 500 Sheets Face Down 500 Sheet Face down 250 Sheets Face Down

100 Sheets Face up 70 Sheet Face up

Others

Max.Monthly Duty 150,000 sheets 200,000 sheets 225,000 sheets - 225,000 sheets Consumable Yeild Standard 10K Standard 10K Standard 6K 17K Standard 18K

High Yield 20K High Yield 20K High Yield 21K High Yield 27K

Power Consumption

Printing : Less than 650 W

Printing : 680 W not_inform Printing: < 593W not_inform

Sleep : under 13 W Sleep : under 20 W Sleep:< 12W Duplex Option Option Option Option NO Options

- Memory (128MB/256MB)

- Memory - 250 sh duplexer - SCF - duplexer

- 3x500 sheet SCF - 500 sheet SCF - 3x250 sh drawer - Memory - 85 envelope

- Duplex - Duplex

- 2000 sh drawer(Max.3850)

- Stand feeder

- 40GB HD - HP Jetdirect

- 85 sh envelope feeder

- Sorter/Mail box - 500 sheet cassette

- 20GB HD

- 650 sh output expander

- 250 sheet cassette

- Stacker & Stapler

- 1850 sh High capacity output stacker

- 40 sheet staple

- 5 bin mailbox

(5x120 sh )

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2.2 Summary of Product

This chapter describes the functions and operating principal of the main component.

2.2.1 Printer Components

2.2.1.1 Front View

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2.2.1.2 Rear View

Product spec and feature

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2.2.1.3 Control Panel

The control panel on the top right side of your printer has the display and the nine buttons.

2.2.1.3(a) Display

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2.2.1.3(b) Overview of Control Panel Menus

The control panel menus are used to configure the printer for your environment. The control panel provides access to the following menus.

Product spec and feature

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2.2.1.3(c) Special Features

Your new printer is equipped with special features that improve the print quality,giving you a competitive edge. You can:

Print with excellent quality and high speed

• You can print up to 1200 x 1200 dpi effective output. See the Software Section.

• Your printer prints A4-sized paper at up to 43 ppm a and letter-sized paper at up to 45 ppm. For duplex printing, your printer prints A4-sized paper at up to 29 ipm b and lettersized paper at up to 30 ipm.

Handle paper flexibly

• The multi-purpose tray supports letterheads, envelopes, labels, transparencies, customsized materials, postcards, and heavy paper. The multi-purpose tray holds up to 100 sheets of plain paper.

• The 500-sheet standard tray 1 supports plain paper in various sizes.

• The 500-sheet optional tray support plain paper in various sizes. You can install up to 3 additional trays.

• Two output tray; select either the output tray (face-down) or the rear cover (face-up) for the most convenient access.

• Straight-through paper path capability from the multi-purpose tray to the rear cover.

Create professional documents

• Print Watermarks. You can customize your documents with words, such as “Confidential.” See the Software Section.

• Print Posters. The text and pictures of each page of your document are magnified and printed across the sheet of paper and can then be taped together to form a poster. See the Software Section.

a. pages per minute b. images per minute

Save your time and money

• This printer allows you to use toner save mode to save toner.

• You can print on both sides of the paper to save paper (double-sided printing) if you use the ML-4551ND or install the optional duplex unit in the ML-4550 and ML-4551N.

• You can print multiple pages on a single sheet of paper to save paper (N-Up printing). See the Software Section.

• You can use preprinted forms and letterhead with plain paper. See the Software Section.

• This printer automatically conserves electricity by substantially reducing power consumption when not in use.

1 2

3 4

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Expand the printer capacity

• Your printer has 128 MB of memory which can be expanded to 512 MB.

• A Network interface enables network printing. You can add an optional network interface card to the ML-4550. The ML-4551N and ML-4551ND come with a built-in network interface, 10/100 Base TX.

• You can add 500-sheet optional trays to your printer. These trays let you add paper to the printer less often.

• A PostScript 3 Emulation* (PS) enables PS printing.

Use the optional hard disk

You can install an optional hard disk in your printer.

• The 40 GB hard disk can store the data from your computer in the print queue. This decreases the workload of the computer.

• You can use various print features, such as storing a job in the hard disk, proofing a job, and printing private documents.

• You can manage the print jobs in the print queue of the printer hard disk. For details.

Print in various environments

• You can print in Windows 98/Me/NT 4.0/2000/XP/2003.

• Your printer is compatible with Linux and Macintosh.

• Your printer comes with both Parallel and USB interfaces.

• You can also use a network interface. The ML-4551N and ML-4551ND come with a built-in network interface, 10/100 Base TX. However, you need to install the optional wired network interface card to the ML-4550.

Printer Features

The table below lists a general overview of features supported by your printer. (I: Installed, O: Option)

Features ML-4550 ML-4551N ML-4551ND

IEEE 1284 Parallel I I I USB 2.0 I I I Network Interface O I I

(Ethernet 10/100 Base TX) Hard Disk O O O PostScript* Emulation I I I Duplex Unit O O I Optional Tray 2 O O O Optional Tray 3 O O O Optional Tray 4 O O O

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2.2.2 System Layout

ƒ Cassette ƒ Duplex ƒ MPF   ƒŁ Print Cartridge ƒØ LSU  ƒŒ Fuser ƒº SMPS & HVPS Board ƒ Duplex Solenoid

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2.2.2.1 Feeding

It is consists of a basic cassette, an MP tray for supplying different types of media : envelope, label special paper, duplex unit, and parts related to paper transferring.

1) Separation method

Separate it from the friction pad mounted to the center of the cassette and apply retard roller that uses a spring clutch. A feed roller uses an electronic clutch to control driving power.

2) Basic cassette

It takes a center loading method and applies 'friction pad separating method.' It means that there is a paper sensor, but a paper size is detected after detecting the first paper by software. Both the side guide and the rear guide can be adjusted for for various types of papers from A5 to legal size paper. It has a paper existence sensing function (Capacity: 500 sheets of general paper), paper arranging function, various size papers accepting function, SCF paper path function, and displaying function of paper remaining amount. In the front side, there is a paper level indicator.

3) Pick-up roller

It has functions such as a paper pickup function, driving control function, paper feeding function, and removing electronic static function.

4) Retard roller

It takes an arrangement method which uses a stopper roller and a weight without electric actuator. It has paper separating function, driving control function, and multi feeding prevention function.

6) Registration roller

It has a paper arranging function, paper transferring function, paper detecting function, jam removing function, and so on.

7) MP tray

It has a paper arranging function, paper transferring function, jam removing function, and so on. It uses rubbing pad method to feed 100 sheets of general papers and 10 envelops. It is possible to extend to 300mm for accepting a legal size paper.

8) Duplex unit

It has paper transferring function, paper guide function, jam removing function, paper sensing function, and main board supporting function. It is designed for basic attachment, and the duplex feeding takes a side feeding method. Usable papers are A4, letter, and legal size paper. For removing a jam occurred in a front part, it is designed to open a cassette and a guide. It is designed to open a rear cover to remove a jam in a rear part. If a face up tray is open, the duplex option cannot be used.

9) SCF (Second Cassette Feeder)

It is the same method with the main cassette, and the capacity is 500 sheets. It has a separate driving mechanism. It is designed for a common use with a main cassette.

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2.2.2.2 Transfer

It consists of a PTL (Pre-transfer Lamp) and a transfer roller. A PTL sheds light on an OPC drum, lowers an electric potential of an OPC drum's surface, and improves the efficiency of the transfer. A transfer roller transfers toner on an OPC drum to the paper. Life span: Print over 150,000 sheets (In 16~27 )

2.2.2.3 Driver Ass'y

By driving the motor, the system takes power. It consists of a main motor for feeding fuser and duplex reverse turn, and a deve-motor for a toner cartridge.

- Main Motor : DC 24V, Rated RPM : 1604rpm

- Deve Motor : DC 24V, Rated RPM : 1424 rpm

2.2.2.4 Fuser

It is consisted of a heat lamp, heat roller, pressure roller, thermistor and thermostat. It sticks the toner on a paper by heat and pressure to complete the printing job.

- E-coil Heator : 1,300 Watt

50W

1) Thermostat

When a heat lamp is overheated, a Thermostat cuts off the main power to prevent over-heating.

- Non-Cotact type Thermostat

3) Heat roller

The heat roller transfers the heat from the e-coil to apply a heat on the paper. The surface of a heat roller is coated with Teflon, so toner does not stick to the surface.

4) Pressure roller

A pressure roller mounted under a heat roller is made of a silicon resin, and the surface also is coated with Teflon. When a paper passes between a heat roller and a pressure roller, toner adheres to the surface of a paper permanently.

5) Items for safety

Protecting device for overheating

- 1st protection device: Hardware cuts off when overheated

- 2nd protection device: Software cuts off when overheated

- 3rd protection device: Thermostat cuts off main power.

Safety device

- A fuser power is cut off when a front cover is opened

- Maintain a temperature of fuser cover's surface under 80(C for user, and attach a caution label at where customer can see easily when customer open a rear cover.

2.2.2.5 LSU (Laser Scanner Unit)

It is the core part of the LBP which switches from the video data received to the controller to the electrostatic latent image on the OPC drum by controlling laser beam, exposing OPC drum, and turning principle of polygon mirror. The OPC drum is turned with the paper feeding speed. The /HSYNC signal is created when the laser beam from LSU reaches the end of the polygon mirror, and the signal is sent to the controller. The controller detects the /HSYNC signal to adjust the vertical line of the image on paper. In other words, after the /HSYNC signal is detected, the image data is sent to the LSU to adjust the left margin on paper. The one side of the polygon mirror is one line for scanning.

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2.2.2.6 Print Cartridge

By using the electronic photo process, it creates a visual image. In the print cartridge, the OPC unit and the toner cartridge unit are in a body. The OPC unit has OPC drum and charging roller, and the toner cartridge unit has toner, supply roller, developing roller, and blade (Doctor blade)

- Developing Method: Non-contacting method

- Toner : Non magnetic 1 component pulverized type toner

- The life span of toner : 10,000 or 20,000 pages (LSA Pattern/A4 standard)

- Toner remaining amount detecting sensor : Yes

- OPC Cleaning : Cleaning blade type

- Management of disusable toner : Collect the toner by using Cleaning Blade

- OPC Drum protecting Shutter : Yes

- Classifying device for toner cartridge : ID is classified by CRUM.

Cleaning Roller

Cleaning Blade

-650V

200V

-1.30KV

= 1500V, f = 3.0KHz

+5.0kV

-50V

200V

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2.2.3 Engine H/W Specifications

2.2.3.1 ML-4550 (PCL) Main Board

The Engine Board and the Controller Board are in one united board, and it is consisted of CPU part and print part in functional aspect. The CPU is functioned as the bus control, O/O handling, drivers, and PC interface. The main board sends the Current Image by Video data to the LSU and manages the conduct of Electrophotography for printing. It is consisted of the circuits of the motor (paper feed, pass) driving, clutch driving, pre-transfer lamp driving, current driving, and fan driving. The signals from the paper feed jam sensor and paper empty sensor are directly inputted to the main board.

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2.2.3.1(a) Asic (ORION 2)

Marvell Feroceon 2850 ARM Compatoble (I-Cache: 32KB, D-Cache-32KB) 64-bit RISC embedded processor core Dual bus architecture for bus traffic distribution

- AMBA High performance Bus (AHB)

- System Bus with SDRAM

- 64-bit Mbus Crossbar extension Interface with Flash and Device port

SDRAMC

- 32 Bits Dual mode DDR-II, 200MHz

- 4 Banks (Up to 256MB per Bank)

Device Controller

- Boot Flash 1 Bank (Up to 128MB)

- Device/NOR Flash 3 Banks (Up to 128MB per Bank)

No Graphic Execution Unit and Image processor No Codec (Encoding / Decoding) Printer Video Controller Interface for LBP engines

- Hyper-C : Printer Video Controller with RET algorithm (Line Memory & Lookup Table Memory : 512 x 8 , 4096 x 16)

Dual / Single Beam, LVDS Pad (VDO, HSYNC)

PCI Controller

- 32Bits, 66MHz (PCI) / 133MHz (PCI-X)

- PCI Local Bus Specification rev. 2.2 compliant

- PCI Express Specification beta 1.0a compliant

- Host /Agent Mode (Support 3+4 Express Devices in Host Mode)

Engine Controller (LPEC1)

- LSU Interface unit

- Step Motor: 2 Channels

- PWM: 8 Channels

- ADC: 6 Channels

USB 2.0 Interface with Embedded USB 2.0 PHY Gigabit Ethernet Controller

- IEEE 802.3 compliant with 10/100/1000 Mbps full-duplex GbE port

- Support GMII,MII and RGMII interface with external PHY/SERDES device

Package : 496pins PBGA Power : 1.2V(Core), 3.3V(IO) power operation Speed : 600MHz core(ARM9 Compatible) operation, 200MHz bus operation

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2.2.3.1(b) Memory

NOR Flash Memory : It stores System Program and downloads the System Program through PC Interface, and in

case of model for export it compresses the PCL font, then stores it.

- Capacity : 128M Byte

- Access Time : 70 nsec

DDR SDRAM : It is used as Swath Buffer, System Working Memory Area, etc. when printing. It stores Font List, compressed into Flash memory, on DRAM and uses it as PCL font in case of model for export.

- Capacity : 128 Byte(Basic), up to 512Mbyte (User Option)

- Type : DDR-II SDRAM 200MHz , 32bit

2.2.3.1(c) Others

The Option PBA can be mounted for supporting the serial communication.

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2.2.3.1(d) 88F5281 Internal Block Diagram

Dual Channel

32 bit up to 200 MHz

DDR1/DDR2

SDRAM Controller

Feroceon CPU

32 KB

Dcache

32 KB

Icache

PCI/PCI-X

64-bit

port

Mbus-L to

Mbus

Bridge

Mbus ? Crossbar extension)

64 bit @ 166 MHz

GPPs,

UART x 2,

TWSI,

Flash

PCI-

Express

x 1 port

Gigabit

Ethernet

port

USB 2.0

port

Local bus ? 4 bit up to 200 MHz

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2.2.3.1(e) Sensor Input Circuit

Paper Empty Sensing

The Paper empty sensor (Photo Interruptor) on the engine board informs the state of paper to CPU whether it is empty or not with operation of the actuator.

When cassette is empty, it detects the fact by reading the D0 Bit of CPU, and then informs the fact by selecting the second LED(yellow) among the panel LEDs.

MP Sensing

By operation of Actuator on the frame, MP Sensor (Photo interruptor) on the engine board informs the state of paper to CPU whether it is empty or not. It reads the D0 Bit of CPU for recognizing paper in MP, and paper is fed from MP if there is.

Paper Feeding/Width Toner Cartridge Sensing

When paper passes the actuator (feed sensor part), it detects the signal of Photo interrupter, informs the paper feeding state to CPU, and then sprays the image data after certain time.

If it doesn’t detect the feed sensor within 1sec. after paper is fed, paper Jam0 (CPU #_ ) is occurred (Red and Yellow will be turned on among the OP panel LEDs), and the fact whether the developer is inserted or not is detected with the same principle. After the developer is mounted, the actuator is operated. The signal from the photo interrupter is detected when it is passing the actuator of the sensor part. That is the developer ID sensing.

Paper Exit Sensing

It detects paper state whether paper gets out from the set with operation of exit sensor on the engine board and actuator on the frame. Paper detects the on/off time of exit sensor by reading D2 Bit of CPU, and the normal operation or jam information is informed to the CPU.

The paper JAM2 is informed. (Red, Yellow LED will be turned on among the OP panel LEDs)

Cover Open Sensing

The Cover open sensor is located on the front cover. After the front cover is opened, +24V (DC fan, Solenoid, Main Motor, Polygon motor part of LSU and HVPS), which is supplied to the each unit, is cut off. The cover-open sensing is operated by the D0 bit of CPU, and the developer ID sensing is operated by D7 bit of CPU.

In case, the red LED among OP pnael LEDs will be ON for informing the facts to user.

DC FAN / SOLENOID Driving

It is driven by transistor and controlled by D6 bit of CPU. When it is high, the fan is driving by turning on the TR, and it is off when the sleep mode is selected. There are two sole-

noids, and they are driven by paper pick-up and MP signal. It is turned on or off by D4 bit of CPU, and its driving time is 300ms. The diode protects the driving TR from the noise pulse, which is flown when the solenoid id de-energizing.

FAN Driving Circuit is driven by Transistor, and controlled by D6 Bit of

Motor Driving

The motor driving circuit is formed when the Driver IC is selected in the first place. The A3977 Motor Driver IC is used in this case. But resistance Rs value of sensing and voltage value of the V reference can be changed by motor driving voltage value. The motor driving voltage is calculated with the following formula.

I = Vref / Rs, wherein Vref is (R1x 5V) / (R1+R2).

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