Brother QL 570 - P-Touch B/W Direct Thermal Printer User manual

P-touch
SERVICE MANUAL
MODEL: QL-570

PREFACE
This publication is a service manual covering the specifications, theory of operation,
disassembly/reassembly procedure, and troubleshooting the Brother QL-570. It is intended for
service personnel and other concerned persons to accurately and quickly provide after-sale service
for our QL-570.
To perform appropriate maintenance so that the machine is always in best condition for the
customer, the service personnel must adequately understand and apply this manual.
This manual is made up of four chapters and appendices.
CHAPTER I SPECIFICATIONS
CHAPTER II THEORY OF OPERATION
CHAPTER III DISASSEMBLY AND REASSEMBLY
CHAPTER IV TROUBLESHOOTING AND ERROR MESSAGE
APPENDIX 1. MAINTENANCE SOFTWARE OPERATION
© Copyright Brother 2007
All rights reserved.
No part of this publication may be reproduced in any
form or by any means without permission in writing
from the publisher.
Specifications are subject to change without notice.

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CONTENTS
CHAPTER I SPECIFICATIONS .......................................................................... I-1
1.1 MECHANICAL SPECIFICATIONS ........................................................................... I-1
1.1.1 External Appearance ......................................................................................... I-1
1.1.2 Keyboard............................................................................................................ I-1
1.1.3 Display ............................................................................................................... I-2
1.1.4 Printing Mechanism ........................................................................................... I-2
1.1.5 Thermal Tape..................................................................................................... I-3
1.1.6 Cutter ................................................................................................................. I-4
1.1.7 PC Interface ....................................................................................................... I-4
1.2 ELECTRONICS SPECIFICATIONS ......................................................................... I-4
1.2.1 Character Generator.......................................................................................... I-4
1.2.2 Power Supply..................................................................................................... I-4
CHAPTER II THEORY OF OPERATION............................................................ II-1
2.1 OUTLINE OF MECHANISMS ................................................................................... II-1
2.1.1 Print Mechanism ................................................................................................ II-1
2.1.2 Press Contact and Release Mechanism of Thermal Head ............................... II-2
2.1.3 Tape Feed Mechanism ...................................................................................... II-3
2.1.4 Automatic Tape Full Cutter Mechanism ............................................................ II-4
2.1.5 Cover Open (Cover Lock) Sensor ..................................................................... II-5
2.2 OUTLINE OF CONTROL ELECTRONICS ............................................................... II-6
2.2.1 Main PCB ASSY ................................................................................................ II-6
2.2.2 Media Type Detect Switch PCB (Media PCB ASSY) ........................................ II-6
2.2.3 Media Position Detect Sensor PCB (Tape Sensor PCB ASSY)........................ II-6
2.2.4 Key, LED PCB (SB PCB ASSY) ........................................................................ II-7
2.2.5 Cutter Sensor (Cutter Home Position Detect Sensor)....................................... II-7
2.2.6 Media Feed Motor (Tape Feed Motor ASSY).................................................... II-7
2.2.7 Full Cutter Motor (Cutter Motor ASSY).............................................................. II-7
2.2.8 Thermal Head .................................................................................................... II-7

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2.3 MAIN PCB................................................................................................................. II-8
2.3.1 Logic Components ............................................................................................. II-9
[ 1 ] CPU ................................................................................................................ II-9
[ 2 ] EEPROM ........................................................................................................ II-9
2.3.2 Key, LED Circuit................................................................................................. II-9
2.3.3 Head and Motor Power Supply ON/OFF Circuit................................................ II-10
2.3.4 Full Cutter Motor Driver Circuit and Media Feed Motor Driver Circuit............... II-11
2.3.5 Media Type Detect Sensor Circuit, Media Position Detect Sensor Circuit
and Cover Open Sensor Circuit ........................................................................ II-12
2.3.6 Head Temperature Detect Circuit...................................................................... II-15
2.3.7 Cutter Home Position Detect Sensor Circuit ..................................................... II-15
2.3.8 Reset Circuit ...................................................................................................... II-16
2.3.9 USB Interface Circuit ......................................................................................... II-16
CHAPTER III DISASSEMBLY AND REASSEMBLY.......................................... III-1
3.1 SAFETY PRECAUTIONS ......................................................................................... III-1
3.2 TIGHTNING TORQUE LISTS................................................................................... III-2
3.3 LUBRICATION POINTS LIST................................................................................... III-3
3.4 DISASSEMBLY PROCEDURE................................................................................. III-5
[ 1 ] Removing the Top Cover and Thermal Tape ................................................. III-5
[ 2 ] Removing the Front Cover and Tray S........................................................... III-7
[ 3 ] Removing the Power Supply ASSY and Main PCB ASSY............................. III-8
[ 4 ] Removing the Sub ASSY Inlet........................................................................ III-12
[ 5 ] Removing the Media PCB ASSY.................................................................... III-13
[ 6 ] Removing the Side Cover L, R ....................................................................... III-14
[ 7 ] Removing the Panel Cover............................................................................. III-17
[ 8 ] Removing the Upper Cover ............................................................................ III-19
[ 9 ] Removing the Mecha ASSY ........................................................................... III-21
[ 10 ] Removing the Cutter Unit ASSY..................................................................... III-22
[ 11 ] Disassembly of the Mecha ASSY ................................................................... III-23
3.5 REASSEMBLING PROCEDURE.............................................................................. III-28
[ 1 ] Reassembling the Mecha ASSY .................................................................... III-28
[ 2 ] Installing the Cutter Unit ASSY....................................................................... III-34

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[ 3 ] Installing the Mecha ASSY ............................................................................. III-35
[ 4 ] Installing the Upper Cover .............................................................................. III-36
[ 5 ] Installing the Panel Cover............................................................................... III-39
[ 6 ] Installing the Side Cover L, R ......................................................................... III-42
[ 7 ] Installing the Media PCB ASSY...................................................................... III-44
[ 8 ] Installing the Sub ASSY Inlet.......................................................................... III-44
[ 9 ] Installing the Power supply ASSY and Main PCB ASSY ............................... III-46
[ 10 ] Installing the Front Cover and Tray S............................................................. III-50
[ 11 ] Installing the Top Cover and Thermal Tape ................................................... III-51
[ 12 ] Demonstration Print and Final Check............................................................. III-53
CHAPTER IV TROUBLESHOOTING AND ERROR MESSAGE........................ IV-1
4.1 PRECAUTIONS ........................................................................................................ IV-1
4.2 AFTER REPAIRING.................................................................................................. IV-1
4.3 LED CONTROL IN DIFFERENT SITUATIONS AND MEASURE AGAINST
ERRORS................................................................................................................... IV-2
4.4 ERROR MESSAGE .................................................................................................. IV-3
4.5 TROUBLESHOOTING FLOWS ................................................................................ IV-6
[ 1 ] Printing is performed with specific dots omitted ............................................. IV-6
[ 2 ] The tape is not detected correctly .................................................................. IV-7
[ 3 ] LED does not turn on...................................................................................... IV-8
[ 4 ] No printing is performed ................................................................................. IV-9
[ 5 ] The interface malfunction ............................................................................... IV-9
[ 6 ] The tape is not cut .......................................................................................... IV-10
[ 7 ] The tape is not fed correctly ........................................................................... IV-11
APPENDIX 1 MAINTENANCE SOFTWARE OPERATION................................ 1
APPENDIX 1.1 Purpose and Use Procedure of the Reset Software Tool
(ql500tstReset.exe) ................................................................................. 3
APPENDIX 1.2 Setting and Use Procedures of the Maintenance Software Tool
(ql570tstSE.exe)...................................................................................... 6
APPENDIX 1.3 Use Procedure of the VR Adjustment Tool
(ql500tstVRAdjust.exe) ........................................................................... 25
APPENDIX 1.4 Auto Power-OFF Setting Tool
(autopoff.exe)........................................................................................... 31

I-1
CHAPTER I SPECIFICATIONS
1.1 MECHANICAL SPECIFICATIONS
1.1.1 External Appearance
[ 1 ] Dimensions (W x D x H) 134mm x 208mm x 141mm
(Excluding the bottom legs)
[ 2 ] Weight Approx. 1.12kg (Machine proper only)
Approx. 2.12kg (In package)
Fig. 1.1-1 External Appearance
1.1.2 Keyboard
[ 1 ] Number of function keys 3 (ON/OFF button, Feed button, Cut button)
[ 2 ] Key arrangement See Fig. 1.1-2.
Fig. 1.1-2 Key Arrangement
Feed button Cut button LED lamp ON/OFF button
141mm 134mm
208mm

I-2
1.1.3 Display
[ 1 ] Display type LED 1 (ON/OFF: Green light ON/OFF,
Error: Red light blinking,
Cover Opened: Orange light ON,
Cooling: Orange light blinking)
1.1.4 Printing Mechanism
[ 1 ] Print method Direct thermal printing with thermal head
Printing on thermal paper tape, and printing on
thermal paper and thermal plastic tape (with fixed
head and tape feeding)
[ 2 ] Highest printing speed Max. 68 labels/min. (Standard address labels)
[ 3 ] Print head
Type Thick film thermal head
720 dots by one row
Resolution 300 dpi

I-3
1.1.5 Thermal Tape
[ 1 ] Tape Roll type (Die cut and free length)
[ 2 ] Type and size of die cut tape
Type of tape Label size
(W x H)
Roll overall
width
Number of label
sheets
Standard Address 29mm x 90mm 32mm 400 sheets/roll
Large Address 38mm x 90mm 42mm 400 sheets/roll
Small Address 62mm x 29mm 66mm 800 sheets/roll
Shipping 62mm x 100mm 66mm 300 sheets/roll
Multi purpose 17mm x 54mm 19mm 400 sheets/roll
File Folder 17mm x 87mm 19mm 300 sheets/roll
CD/DVD OD φ58mm
ID φ16mm
66mm 100 sheets/roll
Square Paper 23mm x 23mm 32mm 1000 sheets/roll
Round Paper 12 OD φ12mm 32mm 1200 sheets/roll
Round Paper 24 OD φ24mm 32mm 1000 sheets/roll
Standard Address
(For supply with machine)
29mm x 90mm 32mm 100 sheets/roll
[ 3 ] Type and size of free length tape
Type of tape Roll width Roll overall
width
Effective length
of roll
Continuous Length Paper 12 12mm 32mm 30.48m
Continuous Length Paper 29 29mm 32mm 30.48m
Continuous Length Paper 62 62mm 66mm 30.48m
Continuous Length Paper 62
White Removable
62mm 66mm 30.48m
Continuous Length Paper 62
Yellow Removable
62mm 66mm 30.48m
Continuous Length Film-White 29 29mm 32mm 15.24m
Continuous Length Film-White 62 62mm 66mm 15.24m
Continuous Length Film-Yellow
62
62mm 66mm 15.24m
Continuous Length Film-Clear 62 62mm 66mm 15.24m
Continuous Length Paper 62
(For supply with machine)
62mm 66mm 8m

I-4
1.1.6 Cutter
[ 1 ] Tape cutting Automatic cut
1.1.7 PC Interface
[ 1 ] Method USB
Standard USB Standard Ver.2.0 Full speed
[ 2 ] Supported OS Microsoft Windows 2000 Professional
Microsoft Windows XP Professional
Microsoft Windows XP Home Edition
Microsoft Windows Vista
[ 3 ] Printer emulation PT CBP (Brother original)
[ 4 ] Accessories
Editor Dedicated editor is included.
USB IF cable Standard USB cable is included.
1.2 ELECTRONICS SPECIFICATIONS
1.2.1 Character Generator
Note: Character generator feature is not provided for QL-570.
[ 1 ] Demonstration printing
Press the Feed button once while pressing and holding the power supply key when
power is off, and then release the ON/OFF button. Demonstration printing will be
started.
Fig. 1.2-1 Demonstration Printing
1.2.2 Power Supply
Integral switching power supply U.S.A. / Canada: 120V AC 60Hz
Europe, Other regions: 220V to 240V AC 50/60Hz

II- 1
CHAPTER II THEORY OF OPERATION
2.1 OUTLINE OF MECHANISMS
2.1.1 Print Mechanism
■ Structure of Thermal Head
This machine adopts direct thermal printing system. The thermal head consists of 720 pieces of
heating elements arrayed in vertical single row as shown in the Fig.2.1-1. The dimension of
each heating element is vertical length 0.0847 (0.0847mm pitch) x horizontal width 0.13mm.
Fig. 2.1-1 Heating Elements of Thermal Head
■ Printing Process
A thermal tape is pressed again the thermal head in the printing process by the force comes from
a nip between the cylindrical rubber platen and the thermal head. At this timing, voltage is
applied selectively to 720 pieces of heating elements arrayed on the thermal head. By this
voltage application, the heating elements generate heat and the thermal tape develops dots by
itself at heat sensing points. After application of voltage the thermal tape is fed to the next
printing position by the platen (0.0847mm). This printing cycle is repeated and characters and
geometries are printed on the tape.
One time travel distance (0.0847mm) is shorter than the width of a heating element (0.13mm), so
that continuous printing cycle can print characters and geometries on a tape by developing dots
with no gap.

II- 2
2.1.2 Press Contact and Release Mechanism of Thermal Head
The head ASSY is pressed firmly against on the platen ASSY by the force of head spring L. When
open the top cover, the release gear and release shaft are turned via link lever and platen release
lever and the release shaft presses down the head ASSY. This movement releases the head
ASSY from the platen ASSY. Tape can be set under this condition.
To press the head ASSY firmly against the platen ASSY, close the top cover. This close motion
can automatically press the head ASSY firmly against the platen ASSY.
Fig. 2.1-2 Press Contact and Release Mechanism of Thermal Head
Release gear
Top cover
Platen release
lever
Release shaft
Head ASSY
Platen ASSY
Link lever
Head spring L
Top cover
Platen release lever

II- 3
2.1.3 Tape Feed Mechanism
When the tape is fed, the tape is pressed against the thermal head, which is nipped between the
platen and the thermal head. Here, the tape feed motor ASSY (step motor) rotates, of which drive
power is transmitted via the gear train to the platen gear and the platen, and consequently the
platen can feed the tape.
Fig. 2.1-3 Tape Feed Mechanism
Double gear C
Thermal head
Platen
Platen gear
Thermal tape
Tape feed motor ASSY
Double gear B
Double gear A

II- 4
2.1.4 Automatic Tape Full Cutter Mechanism
The automatic tape full cutter mechanism moves the moving cutter blade up and down to the
direction of the fixed cutter blade to cut the tape on the feeding pass. The cam is rotated once so
that the moving cutter blade moves up and down and cuts a medium. The cutter motor ASSY
rotates from the position where the cutter home position detect sensor is ON, and the gear of the
cam is rotated through the cut worm gear. When the cam is rotated once, the cutter motor stops
and stays again at the position where the cutter home position detect sensor is ON.
This mechanism provides the mechanism to reverse the driving system, which is used in case that
the tape or the like is jammed between the blades. (For the details, refer to “CHAPTER IV
TROUBLESHOOTING & ERROR MESSEAGE”.)
When the driving system is reversed, the cutter motor stops and stays again at the position where
the cutter home position detect sensor is ON.
Fig. 2.1-4 Automatic Tape Full Cutter Mechanism
Thermal tape
Cut helical gear
Cut worm gear
Cutter motor ASSY
Fixed cutter blade
Moving cutter blade
A view
< A view > Fixed cutter blade
Moving cutter
blade
Cutter motor ASSY
Cutter home
position detect
sensor
Cut helical
gear
Cut worm gear

II- 5
2.1.5 Cover Open (Cover Lock) Sensor
The cover open (cover lock) sensor (push switch) is mounted on the SB PCB ASSY. Closing the
top cover, the cover sensor arm pushes the cover open (cover lock) sensor (push switch) and the
signal of top cover close status is output.
Fig. 2.1-5 Cover Open (Cover Lock) Sensor
SB PCB ASSY
Top cover
Cover open
(cover lock) sensor
(push switch)
D
Cover sensor arm
Top cover
Cover open (cover lock) sensor
(push switch)
SB PCB ASSY
Cover sensor arm
Rib

II- 6
2.2 OUTLINE OF CONTROL ELECTRONICS
Fig. 2.2-1 shows the block diagram of the control electronics. The control electronics consist of
the following components.
Fig. 2.2-1 Block Diagram of the Control Electronics
2.2.1 Main PCB ASSY
This manages all the components. This PCB consists of CPU, EEPROM, USB chip and motor
drivers etc.
2.2.2 Media Type Detect Switch PCB (Media PCB ASSY)
The sensor (mechanical SW) that detects media type and size is connected to main PCB ASSY.
A semi-fixed resistance (VR) for adjustment of the media position detect sensor is mounted on it.
2.2.3 Media Position Detect Sensor PCB (Tape Sensor PCB ASSY)
This sensor detects the printing start position for the die cut label, and checks existence of the
zebra pattern media using refection type photo sensor for the free length label.

II- 7
2.2.4 Key, LED PCB (SB PCB ASSY)
This is the PCB equipped with ON/OFF button, Feed button, Cut button, cover open sensor and
LED lamp (Green/Red).
2.2.5 Cutter Sensor (Cutter Home Position Detect Sensor)
This sensor detects existence of the cutter at its home position (micro switch).
2.2.6 Media Feed Motor (Tape Feed Motor ASSY)
The media feed motor supplies the drive power to feed media. This motor is φ35 diameter of step
motor of which drive voltage is VH (25V).
2.2.7 Full Cutter Motor (Cutter Motor ASSY)
The cutter motor supplied the drive power to cut media. This motor is a DC motor of which drive
voltage is VH (25V).
2.2.8 Thermal Head
Thermal head is thick film and drive built-in type thermal head, which consists of 720 dots by
one row/300dpi. The drive voltage is VH (25V).

II- 8
2.3 MAIN PCB
Fig. 2.3-1 shows the block diagram of the main PCB. The main PCB consists of the following
components.
(1) CPU (Including ROM and RAM)
(2) EEPROM (4Kbit)
(3) Power supply ON/OFF circuit, Feed button ON/OFF circuit, Cut button ON/OFF circuit, LED
ON/OFF circuit
(4) Head power supply ON/OFF circuit
(5) Full cutter motor driver circuit and Media feed motor driver circuit
(6) Media type detect sensor circuit, Media position detect sensor circuit and Cover open sensor
circuit
(7) Head temperature detect circuit
(8) Cutter home position detect sensor circuit
(9) Reset circuit
(10) USB interface circuit
Fig. 2.3-1 Block Diagram of Main PCB

II- 9
2.3.1 Logic Components
[ 1 ] CPU
CPU (U7) controls and manages the entire system, which is 32 bit microcomputer of NEC
brand. This CPU contains the 256 Kbyte ROM that stores the control program data. The
embedded 24 Kbyte RAM is used mainly for temporary storage of incoming data from PC.
[ 2 ] EEPROM
One 4Kbit EEPROM (U2) is used. This memory is used for write and storage of Vendor ID
code, Product ID code and mechanical information. If the main PCB ASSY is replaced, it is
needed to write the serial number printed on the EEPROM mounted on the main PCB ASSY
and the mechanical configuration data. For this operation, refer to “APPENDIX 1
MAINTENANCE SOFTWARE OPERATION”.
2.3.2 Key, LED Circuit
(1) Power supply ON/OFF circuit
This circuit detects the state of ON/OFF of the ON/OFF button. Pressing this button in the
power supply OFF state (LED OFF), LOW signal is sent to the CPU. Then the CPU starts
initializing process and establishes the status of power supply ON (LED ON and ready for
data acceptance from PC). Pressing this button in the condition that the status of power
supply is ON and the status of ready for data acceptance from PC (LED ON), the CPU starts
power OFF process, turns the LED OFF and changes the status into power supply OFF (LED
OFF). Pressing this button in the condition that the status of power supply is ON and now
going on printing, the CPU stops printing, starts power OFF process after reading and
discarding the data sent from PC, and changes the status into power supply OFF (LED OFF).
(2) Feed button ON/OFF circuit
Pressing this button, this circuit activates the tape feed motor ASSY and it feeds a medium by
a certain distance. This motion does not involve printing.
(3) Cut button ON/OFF circuit
Pressing this button, this circuit activates the cutter motor ASSY and it cuts a medium.
(4) LED ON/OFF circuit
This circuit turns the LED on, off and makes it blinking according to the status of power
supply ON/OFF and some error conditions. For more details, refer to section “4.3 LED
Control in Different Situations and Measure Against Errors”.
SWLEDPCB
Fig. 2.3-2 Key, LED Circuit

II- 10
2.3.3 Head and Motor Power Supply ON/OFF Circuit
Turning the CPU status of PDL10 (VHON, 81 pin) to High, top cover is closed, and turns cover
open sensor Low, Q10 turns on, VH (25V power supply) turns on and consequently the head and
motor is energized.
In addition, turning on this circuit, “media position detect sensor circuit”, “cutter home position detect
circuit” are energized.
Turning the CPU status of PDL10 (VHON, 81 pin) to Low, Q10 turns off, or keeping the top cover
open, Q2 turns on, then these condition make VH (25V power supply) turns off and consequently
the head and motor power supply is cut off.
VHONcircuit
Fig. 2.3-3 Head and Motor Power Supply ON/OFF Circuit

II- 11
2.3.4 Full Cutter Motor Driver Circuit and Media Feed Motor Driver Circuit
(1) Full Cutter motor driver circuit
This circuit drives the DC motor to cut a medium as described in subsection “2.1.4 Automatic
Tape Full Cutter Mechanism”. When the CPU receives cut request from the “Cut button
ON/OFF circuit (refer to 2.3.2(3))”, it confirms that the top cover ASSY is closed, and turns
VHON (81 pin) high. Then the CPU controls C_DCF (37 pin) and C_DCR (38 pin) to driver
the cutter motor.
(2) Media feed motor driver circuit
When the CPU receives feed request from the “Feed button ON/OFF circuit (refer to
2.3.2(2))”, it confirms that the top cover ASSY is closed, and turns VHON (81 pin) high.
Then the CPU controls SIN 1 (44 pin) through SIN 6 (49 pin) to driver the media feed motor.
DC motor driver circuit
(Full cutter motor) Step motor
Fig. 2.3-4 Full Cutter Motor Driver Circuit and Media Feed Motor Driver Circuit