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Seiko LTPH245 Technical Reference

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

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  • Page 1 LTPH245 LINE THERMAL PRINTER MECHANISM TECHNICAL REFERENCE U00055332011 Seiko Instruments Inc.
  • Page 2 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.
  • Page 3 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.

  • Page 4: Table Of Contents

    TABLE OF CONTENTS Section Page CHAPTER 1 PRECAUTIONS SAFETY PRECAUTIONS .................... DESIGN AND HANDLING PRECAUTIONS ..............1.2.1 Design Precautions ..................1.2.2 Handling Precautions ..................1.2.3 Precautions on Discarding ................CHAPTER 2 FEATURES CHAPTER 3 SPECIFICATIONS GENERAL SPECIFICATIONS ..................HEAT ELEMENT DIMENSIONS .................. PAPER FEED CHARACTERISTICS................
  • Page 5 Section Page PLATEN POSITION SENSOR ..................3-28 3.8.1 General Specification ..................3-28 3.8.2 Sample External Circuit .................. 3-28 MODEL CODE LABEL ....................3-29 CHAPTER 4 CONNECTING EXTERNAL CIRCUITS THERMAL HEAD CONTROL TERMINALS..............MOTOR AND SENSOR TERMINALS ................. CAUTION IN CONNECTION ..................CHAPTER 5 DRIVE METHOD THERMAL HEAD DRIVE TIMING................
  • Page 6 FIGURES Figure Page Heat Element Dimensions .................... Print Area........................Sample Drive Circuit..................... Input Voltage Signals for the Sample Drive Circuit ............Motor Start/Stop Timing....................Motor Drive Timing Chart (in use at temperature over -5℃)........3-10 Motor Drive Timing Chart (in use at temperature under -5℃) ........3-11 Thermal Head Block Diagram ..................
  • Page 7 TABLES Table Page General Specifications ....................Sample Motor Drive Frequency ................... General Specifications of the Motor ................Excitation Sequence..................... Acceleration Steps ....................... 3-12 Blocks and Activated Heat Elements ................3-15 Head Resistance Ranks....................3-15 Head Voltage........................ 3-16 Thermal Head Electrical Characteristics ..............3-17 3-10 Activation Pulse Width....................

  • Page 8: Safety Precautions

    CHAPTER PRECAUTIONS Read through this manual to design and operate the printer properly. Pay special attention to the precautions noted in each section. 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. ...

  • Page 9: Design And Handling Precautions

    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.
  • Page 10  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. ...

  • Page 11: Handling Precautions

    1.2.2 Handling Precautions To maintain the initial level of performance of the printer and to prevent future problems from occurring, observe the following precautions. Also, include any necessary precautions to ensure the safe operation of your product by users.  To protect the heat elements, ICs, etc.

  • Page 12: Chapter 2 Features

    CHAPTER FEATURES The LTPH245 Line Thermal Printer Mechanism is a compact, high-speed thermal line dot printing mechanism. It can be used with a measuring instrument and analyzer, a POS, a communication device, or a data terminal device. Since the printer can be battery driven, it can easily be mounted onto a portable device such as a hand-held terminal.
  • Page 13  Low noise Thermal line dot printing is used to guarantee low-noise printing.  Realizing easy design of outer case The printer mechanism is designed to fit easily into the outer case, allowing for reduced number of outer case parts. The external dimensions exclude those of the lever and platen frame.

  • Page 14: Chapter 3 Specifications

    CHAPTER SPECIFICATIONS GENERAL SPECIFICATIONS Table 3-1 General Specifications Item Specification Print method Thermal dot line printing Dots per line 384 dots Resolution 8 dots/mm Print width 48 mm Maximum printing speed 200 dot lines/s (25.0 mm/s) (at 5 V) 450 dot lines/s (56.25 mm/s) (at 7.2 V) 500 dot lines/s (62.5 mm/s) (at 8.0 V) Paper feed pitch 0.125 mm...
  • Page 15 Table 3-1 General Specifications (Continued) Item Specification Operating temperature range -30C to 70C No condensation Storage temperature range -35C to 75C No condensation Life span (at 25C and rated energy) Activation pulse resistance 100 million pulses or more (print ratio=12.5%) Abrasion resistance 50 km or more Paper width...

  • Page 16: Heat Element Dimensions

    HEAT ELEMENT DIMENSIONS The printer contains a thermal head with 384 heat elements (dot-size). 48 mm (384 DOTS) 0.125 mm 0.125 mm Figure 3-1 Heat Element Dimensions mm (PAPER WIDTH) 5 mm 5 mm 48 mm (PRINTING WIDTH) 0.125 mm (PAPER FEED PITCH)

  • Page 17: Paper Feed Characteristics

    PAPER FEED CHARACTERISTICS  Paper is fed in a forward direction when the motor shaft is rotating in the normal direction (clockwise) when seen from the motor gear side.  The motor is driven by a 2-2 phase excitation, constant current chopper method and feeds paper 0.125 mm (equivalent to a single dot pitch) every two steps of the motor drive signal.

  • Page 18: Step Motor Characteristics

    STEP MOTOR CHARACTERISTICS Table 3-3 General Specifications of the Motor Item Specification Type Number of phases 4-phase Drive method Bipolar chopper Excitation 2-2 phase 14  10% Winding resistance per phase Rated voltage 4.2 - 8.5 V Rated current 0.23 A/phase, 0.15A/phase Maximum current consumption 0.46 A Drive frequency...
  • Page 19 3.4.1 Motor Drive Circuit (1) Sample Drive Circuit Sample drive circuits for the motor are shown in Figure 3-3. 10F 0.51 LB1843V-E 1/2W 74HC32 10K 3K 0.01F 10%,10% 3K 0.01F 1K 10%,10% 0.01F 74HC123A 10%,10% CTCRL 0.1F 1SS294 1.8K 0.01F (TE85L,F) 1K...
  • Page 20 (2) Excitation Sequence As shown in Table 3-4, the printer feeds paper in the normal direction when the motor is excited in the order of step 1, step 2, step 3, step 4, step 1, step 2, ..On the other hand, to rotate the motor in a reverse direction, drive the motor in the reverse order of: step 4, step 3, step 2, step 1, step 4, step 3, .

  • Page 21: Motor Timing

    3.4.2 Motor Timing Refer to the timing chart in Figure 3-5 when designing the control circuit and/or software for starting and stopping the motor. Also take note of the following precautions: Precautions for Designing the Motor Control Circuit and Software (1) Stop step ...
  • Page 22 (4) Others  Do not print paper in intermittent feed mode. Doing so may deteriorate the printing quality due to irregular paper feeding pitch.  To print characters and bit images, always follow the start step and stop step.  When rotating the motor in the reverse direction (when rotating from CW to CCW, or vise versa), input the start step using the first step time shown in Table 3-5 Acceleration Steps.

  • Page 23: Precautions For Driving The Motor

    3.4.3 Precautions for Driving the Motor (1) Motor Current Control When the motor speed decreases during printing because of the division drive method, the contents of print data, or input data transfer speed, noise and overheating of the motor may occur due to over- torque of the motor.
  • Page 24 In use at temperature below -5C CTCRL1 230mA Start 1st step 2nd step 3rd step 4th step 5th step 6th step (5.78ms) (5.78ms) (3.57ms) (3.33ms) (3.33ms) (3.33ms) (3.33ms) Max speed=300pps Motor speed = 300 pps CTCRL1=”High” First set current: 0.23 (A) Figure 3-7 Motor Drive Timing Chart (in use at temperature below -5C) Acceleration Control When driving the motor, acceleration control is needed to start paper feeding.
  • Page 25 Table 3-5 Acceleration Steps Number of Speed Step Time Steps (pps) (s) start 6580 6580 4066 3140 2636 2311 2028 1828 1675 1553 1456 1374 1302 1242 1191 1144 1103 1065 1031 1000 1000 3-12...

  • Page 26: Structure Of The Thermal Head

    THERMAL HEAD 3.5.1 Structure of the Thermal Head As shown in Figure 3-7, the thermal head of the printer consists of 384 heat elements, and head drivers to drive the heat elements. Serial printing data input from the DAT terminal is transferred to the shift register synchronously with the CLK signal, then stored in the latch register with the timing of the LATCH signal.
  • Page 27 Block6 Block5 Blcok2 Block1 Heat Element Output Driver Latch Register Shift Register LATCH DST6 DST5 DST2 DST1 Thermistor Figure 3-8 Thermal Head Block Diagram 3-14...

  • Page 28: Printed Position Of The Data

    DATA PRINT SEQUENCE 1 2 3 4 5 6 ......382 383 384 LTPH245 PRINTER MECHANISM DATA INPUT SEQUENCE 1 2 3 4 5 6 ..382 383 384 Figure 3-9 Printed Position of the Data...

  • Page 29: Head Resistance

    Head Resistance The LTPH245 head resistance is176  ± 4 %. 3.5.4 Head Voltage The LTPH245 has a built-in head driver IC and control IC. Table 3-7 shows the head voltage. Table 3-4 Head Voltage Item Voltage Range Head drive voltage 4.2 to 8.5 V...
  • Page 30 3.5.6 Thermal Head Electrical Characteristics Table 3-9 Thermal Head Electrical Characteristics (Vdd=4.5 to 5.5V, Ta=0 to 50C) Rated Values Item Conditions Unit Simbol  Head resistance Head drive voltage Head drive current max. common activated dot 64 Logic block voltage Waiting for activation Logic block current fclk=4MHz,DAT=fixed...

  • Page 31: Timing Chart

    3.5.7 Timing Chart Figure 3-10 Timing Chart 3-18...

  • Page 32: Controlling The Head Activation (Dst) Pulse Width

    CONTROLLING THE HEAD ACTIVATION (DST) PULSE WIDTH 3.6.1 Calculation of Head Activation Pulse Width Head activation pulse width is calculated using the following equation (3). To execute high quality printing using the printer, the value that is calculated using the following equation (3) must be adjusted according to the environment the printer is used in.

  • Page 33: Calculation Of Head Activation Voltage

    3.6.3 Calculation of Head Activation Voltage Calculate the applied voltage using equation (5). Equation (5): V=Vp  0.98 - 1.26 Vp: Head activation voltage (V) 3.6.4 Calculation of Head Resistance A drop in voltage occurs depending on the wiring resistance. Calculate the head resistance using equation (6).

  • Page 34: Determination Of Activation Pause Time And Activation Pulse Period

    3.6.5 Determination of Activation Pause Time and Activation Pulse Period Dot lines may be activated in succession to the same thermal dot in order to protect thermal head elements. Determine the activation period (the time from the preceding activation start to the current activation start) which conforms to equation (7) to reserve the pause time.
  • Page 35 3.6.7 Heat Storage Coefficient In high speed printing, a difference in temperature arises between the rise in temperature of the thermal head due to head activation and the temperature detected by the thermistor. Therefore, the activation pulse must be corrected by simulating a rise in the temperature of the thermal head. No correction is needed when the print ratio is low.

  • Page 36: Calculation Sample For The Head Activation Pulse Width

    3.6.8 Calculation Sample for the Head Activation Pulse Width Table 3-10 lists the calculation sample of the head activation pulse width that was calculated using equation (3) and the values obtained using equations (4) to (8). Table 3-10 Activation Pulse Width Motor Drive Frequency (PPS) Head Drive Thermistor...

  • Page 37: Thermistor Resistance

    3.6.9 Thermistor Resistance The resistance of the thermistor at the operating temperature T (C) is determined using the following equation (10). Equation (10): × × － Resistance at operating temperature Tx (C) 15 kΩ  5% (25C) 3450 k  3% Operating temperature (C) EXP (A): The Ath power of natural logarithm e (2.71828) [Rating]...
  • Page 38 Table 3-11 Temperature and Thermistor Resistance Temperature Thermistor Temperature Thermistor (C) Resistance (k) (C) Resistance (k) 375.54 8.63 275.40 7.26 204.55 6.14 153.76 5.22 116.89 4.46 89.82 3.83 69.71 3.30 54.61 2.86 43.17 2.48 34.42 2.17 27.66 1.90 22.40 1.67 18.27 1.47 15.00...

  • Page 39: Detecting Abnormal Temperatures Of The Thermal Head

    3.6.10 Detecting Abnormal Temperatures of the Thermal Head To protect the thermal head and to ensure personal safety, abnormal thermal head temperatures must be detected by both hardware and software as follows:  Detecting abnormal temperatures by software Design software that will deactivate the heat elements if the thermal head thermistor (TH) detects a temperature 80 C or higher (thermistor resistance RTH ...

  • Page 40: Out-Of-Paper Sensor

    OUT-OF-PAPER SENSOR The printer has a built-in out-of-paper sensor (reflection type photo interruptor) to detect whether paper is present or not. An external circuit should be designed so that it detects output from the Out-of-paper sensor and does not activate the thermal head and motor when there is no paper. Doing not so may cause damage to the thermal head or platen roller or shorten the life of the head significantly.

  • Page 41: Platen Position Sensor

    General Specification Maximum rating: DC30V, 0.5A Connection resistance: 200 m or less 3.8.2 Sample External Circuit (5v) LTPH245 R=4.7k CPU Port C=0.1F Switch * When the platen block is open Figure 3-13 Sample External Circuit of the Platen Position Sensor ...

  • Page 42: Model Code Label

    Model Code Label Figure 3-14 shows that the printer is the LTPH245D-C384-E which is made in September 2004. See Figure 7-1 LTP1245D-C384-E Appearance and Dimensions for labeling position. (1) Manufactured year: 2004 (2) Model code: LTP1245D-C384-E (3) Manufactured month: September (X: October, Y: November, Z: December) １...

  • Page 43: Chapter 4 Connecting External Circuits

    CHAPTER CONNECTING EXTERNAL CIRCUITS The printer has a FFC (Flexible Flat Cable) type connector and normal type connector (model No.51021-0900) made by Molex Co., Ltd. to connect to the external circuits. Use the recommended connectors listed in Table 4-1 to connect the printer firmly to the external circuits. Table 4-1 Recommended Connectors External Circuit Number of...
  • Page 44 Table 4-2 Thermal Head Control Terminal Assignments Terminal Signal Name Input/ Function Number Output Input Thermal head drive voltage Input Thermal head drive voltage Input Print data input (serial input) Input Synchronizing signal for print data transfer LATCH Input Print data latch (memory storage) DST6 Input Thermal head print activation instruction signal...

  • Page 45: Motor And Sensor Terminals

    MOTOR AND SENSOR TERMINALS Figure 4-2 shows the terminals of the motor control, out-of-paper sensor and platen position sensor. Figure 4-2 Motor and Sensor Terminals Table 4-3 Motor and Sensor Terminals Assignments Terminal Signal Name Function Number Motor drive signal Motor drive signal Motor drive signal Motor drive signal...

  • Page 46: Caution In Connection

    CAUTION IN CONNECTION Pay attention to the following during installation of the printer.  Always remove or install the thermal head controls vertically while holding the reinforcement portion of the FFC.  Do not bend the FFC. If the FFC must be bent unavoidably, try to do so without removing the reinforcement sheet from the reinforcement portion of the FFC.

  • Page 47: Chapter 5 Drive Method

    CHAPTER DRIVE METHOD THERMAL HEAD DRIVE TIMING  Input of print data Input of DAT and CLK transfer the print data to the shift register in the serial input. “High” means printing and “Low” means no-printing in DAT. DAT data is read in at the rising edge of the CLK inputs.

  • Page 48: Motor Drive Timing

    MOTOR DRIVE TIMING To print, the phase of motors need to be synchronized with that of the thermal head. As example, the print method which divides one dot line to two groups; the block 1,3, and 5 and the block 2,4, and 6, and prints each group data for each step of the motor is described below.
  • Page 49  2nd line, 1st step Drive the motor by one step (3rd step). As to how much step time is output, compare Tm with the time that was taken in the previous step. (1) in case Tm < the time that was taken in the previous step the next closest acceleration step time to the previous step time or Tm, which is longer, is output.
  • Page 50 Figure 5-2 shows an example of the motor drive timing chart. STEP OF STEP OF STEP OF STOP START STEP OF THE 1 DOT LINE THE 2 DOT LINE THE 1 DOT LINE THE 2 DOT LINE LATCH 1,3,5 1,3,5 2,4,6 2,4,6 Block...

  • Page 51: Chapter 6 Housing Design Guide

    CHAPTER HOUSING DESIGN GUIDE SECURING THE PRINTER The main body of the printer and platen must be secured to the outer case separately with screws. 6.1.1 Printer Mounting Method Secure the printer in the 3 locations shown below (a,b,c). Holes A and B are used for positioning the main body of the printer.

  • Page 52: Mounting Platen Block

    6.1.2 Mounting Platen Block Secure the platen block in the 2 locations shown below (a, b). Holes A and B are used for positioning the outer case. Perform positioning of the outer case using A and B. Platen Block Screw (2 pieces) Figure 6-2 How to Secure the Platen Block Recommended Screws The recommended mounting screws are as follows:...
  • Page 53 The positioning of the platen roller is performed on the printer mechanism side. However, if the platen block is not mounted correctly, the platen roller may be pulled by the outer case. This may cause failure when installing and detaching the platen as well as printing failures. Therefore, mount the platen block correctly.

  • Page 54: Precautions For Securing The Printer

    6.1.3 Precautions for Securing the Printer Pay attention to the following when designing the case and securing the printer. Failure to follow these instructions may cause deterioration of print quality, paper skew, paper jam, noise or damage.  Prevent excessive force or torsion when securing the printer. ...

  • Page 55: Layout Of Printer And Paper

    LAYOUT OF PRINTER AND PAPER  The printer can be laid out as shown in Figure 6-4 according to the loading direction of the paper.  Design the paper outlet with an angle of 60 to 90.  Design the paper inlet with an angle of 90 or more. ...

  • Page 56: Positioning The Paper Cutter

    POSITIONING THE PAPER CUTTER Design the position of the paper cutter so that the paper cutter is within the recommended range as shown below. If the distance between the edge of the paper cutter and position reference hole A of the printer is less than 6.9 mm, the paper cutter may interfere with the platen block when it is opened or closed.

  • Page 57: Outer Case Structure

    OUTER CASE STRUCTURE Figure 6-7 shows a sample of an outer case. *1 Provide a gap of a few mm between the printer and the outer case to allow for cooling of the thermal head. *2 When the FFC contacts bottom of the outer case strongly, disconnection and short circuit may occur. Provide a gap between the printer main body and the outer case.

  • Page 58: Chapter 7 Appearance And Dimensions

    CHAPTER 7 APPEARANCE AND DIMENSIONS Figure 7-1 and 7-2 show the appearance and external dimensions of the LTPH245D-C384-E. Figure 7-3 and 7-4 show the appearance and external dimensions of the LTPH245E-C384-E. Figure 7-5 shows the appearance and dimensions of the platen block used for both LTPH245D-C384-E and LTPH245E-C384-E.
  • Page 59 Figure7-1 Appearance and Dimensions (LTPH245D-C384-E)
  • Page 60 Figure7-2 Printer Main Body Appearance and Dimensions (LTPH245D-C384-E)
  • Page 61 Figure7-3 Appearance and Dimensions (LTPH245E-C384-E)
  • Page 62 Figure7-4 Printer Main Body Appearance and Dimensions (LTPH245E-C384-E)
  • Page 63 Unit: mm Figure7-5 Platen Block Appearance and Dimensions...

  • Page 64: Chapter 8 Loading/Unloading Paper And Cleaning

    CHAPTER LOADING/UNLOADING PAPER AND CLEANING LOADING/UNLOADING PAPER PRECAUTIONS 1) Loading paper  Turn the release lever in the direction of the arrow shown in Figure 8-1. Arrow Figure 8-1 Loading Paper (1)  After confirming that the platen block has separated from the printer mechanism, lift the platen block up.
  • Page 65  Insert the paper vertically into the printer. (See Figure 8-2). Pull the paper through the paper outlet and replace the platen block into the printer mechanism. Make sure that the platen block locks with a click.  Opening the platen block exposes the reduction gear which can be damaged if touched. Therefore, take care not to damage the gear when inserting the paper.
  • Page 66 CLEANING PROCEDURE AND PRECAUTIONS When foreign matter adheres between the thermal head and platen roller, it may cause print failure. If accumulation of paper powder or foreign matter is seen, or print quality seems to have deteriorated, clean the thermal head and platen roller. 8.2.1 PRECAUTIONS Do not clean the printer immediately after printing because thermal head and its periphery are...
  • Page 67 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Seiko Instruments LTPH245D-C384-E...

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