Seiko LTPH245 Use and care manual

Seiko Instruments Inc.
LTPH245
LINE THERMAL PRINTER MECHANISM
TECHNICAL REFERENCE
U00055332011

Copyright © 1999-2012 by Seiko Instruments Inc.
All rights reserved.
Seiko Instruments Inc. (hereinafter referred to as “SII”) has prepared this technical reference for use by SII
personnel, licensees, and customers. The information contained herein is the property of SII and shall not
be reproduced in whole or in part without the prior written approval of SII.
SII reserves the right to make changes without notice to the specifications and materials contained herein
and shall not be responsible for any damages (including consequential) caused by reliance on the
materials presented, including but not limited to typographical, arithmetic, or listing errors.
is a trademark of Seiko Instruments Inc.
LTPH245 LINE THERMAL PRINTER MECHANISM TECHNICAL REFERENCE
Document Number U00055332011
First Edition December 1999
Second Edition May 2000
Third Edition December 2000
Fourth Edition March 2001
Fifth Edition August 2001
Sixth Edition December 2001
Seventh Edition March 2003
Eighth Edition March 2005
Ninth Edition July 2006
Tenth Edition April 2007
Eleventh Edition October 2009
Twelfth Edition May 2012

iii
PREFACE
This technical reference describes the specifications and basic operating procedures for the LTPH
series thermal printer mechanism (hereinafter referred to as “printer”).
The LTPH245 series (RoHS compliance) has the following models.
LTPH245D-C384-E
LTPH245E-C384-E
This technical reference usually describes information common to any printer unless otherwise
specified. If the information is different depending on the model, specific model name is mentioned
clearly.
Chapter 1 “Precautions” describes safety, design, and handling precautions. Read it thoroughly
before designing so that you are able to use the product properly.
SII has not investigated the intellectual property rights of the sample circuits included in this
technical reference. Fully investigate the intellectual property rights of these circuits before using.
In particular, SII reserves the industrial property rights for the Heat Storage Simulation described in
Chapter 3. Using it for the other printer is infringement on the industrial property rights.

v
TABLE OF CONTENTS
Section Page
CHAPTER 1 PRECAUTIONS
1.1 SAFETY PRECAUTIONS ............................................................................................ 1-1
1.2 DESIGN AND HANDLING PRECAUTIONS................................................................ 1-2
1.2.1 Design Precautions......................................................................................... 1-2
1.2.2 Handling Precautions...................................................................................... 1-4
1.2.3 Precautions on Discarding .............................................................................. 1-4
CHAPTER 2 FEATURES
CHAPTER 3 SPECIFICATIONS
3.1 GENERAL SPECIFICATIONS..................................................................................... 3-1
3.2 HEAT ELEMENT DIMENSIONS.................................................................................. 3-3
3.3 PAPER FEED CHARACTERISTICS............................................................................ 3-4
3.4 STEP MOTOR CHARACTERISTICS........................................................................... 3-5
3.4.1 Motor Drive Circuit........................................................................................... 3-6
3.4.2 Motor Timing.................................................................................................... 3-8
3.4.3 Precautions for Driving the Motor.................................................................... 3-10
3.5 THERMAL HEAD ......................................................................................................... 3-12
3.5.1 Structure of the Thermal Head........................................................................ 3-12
3.5.2 Printed Position of the Data............................................................................. 3-14
3.5.3 Head Resistance............................................................................................. 3-15
3.5.4 Head Voltage................................................................................................... 3-16
3.5.5 Peak Current ................................................................................................... 3-16
3.5.6 Thermal Head Electrical Characteristics......................................................... 3-17
3.5.7 Timing Chart.................................................................................................... 3-18
3.6 CONTROLLING THE HEAD ACTIVATION (DST) PULSE WIDTH............................. 3-19
3.6.1 Calculation of Head Activation Pulse Width.................................................... 3-19
3.6.2 Calculation of Applied Energy......................................................................... 3-19
3.6.3 Calculation of Head Activation Voltage........................................................... 3-20
3.6.4 Calculation of Head Resistance...................................................................... 3-20
3.6.5 Determination of Activation Pause Time and Activation Pulse Period............ 3-21
3.6.6 Head Activation Pulse Term Coefficient.......................................................... 3-21
3.6.7 Head Storage Coefficient................................................................................ 3-22
3.6.8 Calculation Sample for the Head Activation Pulse Width ............................... 3-23
3.6.9 Thermistor Resistance .................................................................................... 3-24
3.6.10 Detecting Abnormal Temperatures of the Thermal Head............................... 3-26
3.7 OUT-OF-PAPER SENSOR.......................................................................................... 3-27

vi
Section Page
3.8 PLATEN POSITION SENSOR..................................................................................... 3-28
3.8.1 General Specification...................................................................................... 3-28
3.8.2 Sample External Circuit .................................................................................. 3-28
3.9 MODEL CODE LABEL................................................................................................. 3-29
CHAPTER 4 CONNECTING EXTERNAL CIRCUITS
4.1 THERMAL HEAD CONTROL TERMINALS................................................................. 4-1
4.2 MOTOR AND SENSOR TERMINALS ......................................................................... 4-3
4.3 CAUTION IN CONNECTION ....................................................................................... 4-4
CHAPTER 5 DRIVE METHOD
5.1 THERMAL HEAD DRIVE TIMING................................................................................ 5-1
5.2 MOTOR DRIVE TIMING .............................................................................................. 5-2
CHAPTER 6 HOUSING DESIGN GUIDE
6.1 SECURING THE PRINTER ......................................................................................... 6-1
6.1.1 Printer Mounting Method................................................................................. 6-1
6.1.2 Mounting Platen Block..................................................................................... 6-2
6.1.3 Precautions for Securing the Printer............................................................... 6-4
6.2 LAYOUT OF PRINTER AND PAPER .......................................................................... 6-5
6.3 WHERE TO MOUNT THE PAPER HOLDER.............................................................. 6-5
6.4 SETTING THE PAPER ................................................................................................ 6-5
6.5 POSITIONING THE PAPER CUTTER......................................................................... 6-6
6.6 OUTER CASE STRUCTURE....................................................................................... 6-7
CHAPTER 7 APPEARANCE AND DIMENSIONS
CHAPTER 8 LOADING/UNLOADING PAPER AND CLEANING
8.1 LOADING/UNLOADING PAPER PRECAUTIONS ...................................................... 8-1
8.2 CLEANING PROCEDURE AND PRECAUTIONS....................................................... 8-3
8.2.1 PRECAUTIONS .............................................................................................. 8-3
8.2.2 PROCEDURE ................................................................................................. 8-3

vii
FIGURES
Figure Page
3-1 Heat Element Dimensions............................................................................................ 3-3
3-2 Print Area...................................................................................................................... 3-3
3-3 Sample Drive Circuit..................................................................................................... 3-6
3-4 Input Voltage Signals for the Sample Drive Circuit...................................................... 3-7
3-5 Motor Start/Stop Timing................................................................................................ 3-8
3-6 Motor Drive Timing Chart (in use at temperature over -5℃)........................................ 3-10
3-7 Motor Drive Timing Chart (in use at temperature under -5℃) ..................................... 3-11
3-8 Thermal Head Block Diagram...................................................................................... 3-14
3-9 Printed Position of the Data.......................................................................................... 3-15
3-10 Timing Chart................................................................................................................. 3-18
3-11 Thermistor Resistance vs. Temperature...................................................................... 3-24
3-12 Sample External Circuit of the Out-of-Paper Sensor ................................................... 3-27
3-13 Sample External Circuit of the Platen Position Sensor................................................ 3-28
3-14 Model Code Label ........................................................................................................ 3-29
4-1 Thermal Head Control Terminals................................................................................. 4-1
4-2 Motor and Sensor Terminals........................................................................................ 4-3
5-1 Example of Timing Chart of the Thermal Head Driving ............................................... 5-1
5-2 Example of Motor Drive Timing Chart.......................................................................... 5-3
6-1 How to secure the printer............................................................................................. 6-1
6-2 How to secure the Platen Block ................................................................................... 6-2
6-3 Mounting Position of the Platen Block.......................................................................... 6-3
6-4 Paper Path.................................................................................................................... 6-5
6-5 Paper Cutter Mounting Position ................................................................................... 6-6
6-6 The Blade of the Paper Cutter...................................................................................... 6-6
6-7 Sample Outer Case Structure...................................................................................... 6-7
7-1 Appearance and Dimensions (LTPH245D-C384-E).................................................... 7-2
7-2 Printer Main Body Appearance and Dimensions (LTPH245D-C384-E) ...................... 7-3
7-3 Appearance and Dimensions (LTPH245E-C384-E) .................................................... 7-4
7-4 Printer Main Body Appearance and Dimensions (LTPH245E-C384-E)....................... 7-5
7-5 Platen Block Appearance and Dimensions.................................................................. 7-6
8-1 Loading Paper (1)......................................................................................................... 8-1
8-2 Loading Paper (2)......................................................................................................... 8-2
8-3 Cleaning Procedure...................................................................................................... 8-3

viii
TABLES
Table Page
3-1 General Specifications ................................................................................................. 3-1
3-2 Sample Motor Drive Frequency ................................................................................... 3-4
3-3 General Specifications of the Motor............................................................................. 3-5
3-4 Excitation Sequence..................................................................................................... 3-7
3-5 Acceleration Steps ....................................................................................................... 3-12
3-6 Blocks and Activated Heat Elements........................................................................... 3-15
3-7 Head Resistance Ranks............................................................................................... 3-15
3-8 Head Voltage................................................................................................................ 3-16
3-9 Thermal Head Electrical Characteristics...................................................................... 3-17
3-10 Activation Pulse Width.................................................................................................. 3-23
3-11 Temperature and Thermistor Resistance .................................................................... 3-25
3-12 Out-of-Paper Sensor.................................................................................................... 3-27
4-1 Recommended Connectors ......................................................................................... 4-1
4-2 Thermal Head Control Terminal Assignments............................................................. 4-2
4-3 Motor and Sensor Terminals Assignments.................................................................. 4-3

1-1
1
PRECAUTIONS
Read through this manual to design and operate the printer properly.
Pay special attention to the precautions noted in each section.
1.1 SAFETY PRECAUTIONS
Follow these precautions when designing a product using the printer, and include any necessary
precautions and warning labels to ensure the safe operation of your product by users.
Preventing the thermal head from overheating
When electricity is continuously supplied to the thermal head heat element by a CPU or other
malfunction, the thermal head may overheat, causing smoke and fire.
Follow the method described in Section 3.6.10 to monitor the temperature of the thermal head
to prevent overheating.
Turn the printer off immediately if any abnormal conditions occur.
Preventing the user from touching the thermal head and motor
Warn the user not to touch the thermal head, its periphery or motor as they are hot during and
immediately after printing. Failure to follow this instruction may lead to personal injury
including burns.
Also, allow cooling by designing clearance between the head, motor and the outer case.
Preventing the user from touching the rotary drive portion
Design the product so that the motor does not operate when the outer case and platen block
are open. The user could be caught in the motor when the drive gear is exposed.
CHAPTER

1-2
1.2 DESIGN AND HANDLING PRECAUTIONS
To maintain the initial level of performance of the printer and to prevent future problems from occurring,
observe the following precautions.
1.2.1 Design Precautions
If too much energy is applied to the thermal head, it may overheat and become damaged.
Always use the printer with the specified amount of energy.
Do not apply a pulse of 2V and 20 nsec or higher to each signal terminal of the thermal head.
Use C-MOS IC chips (74HC240 or equivalent) for interfacing the CLK, LATCH, DAT and DST
signals of the thermal head.
When turning the power on or off, always DISABLE (put in “Low” state) the DST terminals.
To prevent the thermal head from being damaged by static electricity:
Fix the printer to the Frame Ground (FG) with the FG connector as shown in Figure 7-2.
Connect the GND terminal (SG) to FG through 1 Mresistor so that the electric potential
of the SG of the thermal head and the FG of the printer are equal.
Keep the Vp power off when not printing to prevent the thermal head from becoming
electrically corroded. In addition, design the printer so that the signal GND of the thermal head
and the frame GND of the printer mechanism become the same electric potential.
Wire resistance should be 50 mor less (however the less the better) between the power
supply and the Vp, and the GND terminals on the thermal head controller. Maintain a
considerable distance from signal lines to reduce electrical interference.
The surge voltage between Vp and GND should not exceed 10 V.
As a noise countermeasure, connect the capacitor noted below between the Vdd and GND
terminals near the thermal head control connector.
Vp GND: approximately 10F
Vdd GND: approximately 1F
When turning the power on or off, perform the Vp and Vdd simultaneously or in the order of 1)
and 2) as follows:
At power ON: 1) Vdd (5 V) 2) Vp
At power OFF: 1) Vp 2) Vdd (5 V)
Always monitor the output of the platen position sensor and out-of-paper sensor. Incorrect
activation of the thermal head may damage and reduce the longevity of the thermal head and
the platen.
Design the outer case so that the out-of-paper sensor is not affected by light from outside.
Since a reflection type photo interrupter is used in the out-of-paper sensor, the sensor may be
affected by light from outside.

1-3
Allow for movement of the FFC when designing the outer case because the FFC will shift 1 to 2
mm from the thermal head moving. Also, design the outer case so that it prevents the paper
feed out from being caught in the platen.
Surface of thermal paper may get scratched by backward feed. The backward feed may cause
paper skew and jams depending on paper roll layout and designing of paper holder. Be sure to
confirm performance with your product before using the backward feed.
To prevent deterioration in printing quality due to backlash of the paper feed system, the motor
should be driven 40 steps in a reverse direction and then 40 steps in the normal direction
during initialization, a time after backward feeding and a time after setting/releasing the platen
block.
If printing at a high print ratio for longer length, non-printing area may be colored. Verify the
performance with your actual device.
For the position in which the
platen block should be fixed,
and the way it is mounted,
follow the instructions shown
in Figure 6-3.
Since the printer mechanism
does not have the function to
prevent paper from sliding,
design the outer case so that
the paper is guarded securely.
Design so that the
paper feed load is
0.49N (50 gf) or
less.
As to the center of the rotation of the
cover of the platen block that is
mounted, follow the instructions
shown in Figure 7-1.
The lever should be used when removing and
installing the platen block. It should never be
pulled by force.