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SII LTP3445 Technical Reference

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LTP3445
LINE THERMAL PRINTER MECHANISM
TECHNICAL REFERENCE
39019-2392-02
Seiko Instruments Inc.

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Summary of Contents for SII LTP3445

  • Page 1 LTP3445 LINE THERMAL PRINTER MECHANISM TECHNICAL REFERENCE 39019-2392-02 Seiko Instruments Inc.
  • Page 3 Seiko Instruments Inc. (SII) has prepared this manual 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 4 Chapter 7 describes safety precautions. Read it thoroughly before designing so that you are able to use the LTP3445 properly. SII has not investigated the intellectual property rights of the sample circuits included in this manual. Fully investigate the intellectual property rights of these circuits before using.

  • Page 6: Table Of Contents

    TABLE OF CONTENTS Section Page CHAPTER 1 FEATURES CHAPTER 2 SPECIFICATIONS 2.1 GENERAL SPECIFICATIONS....................2-1 2.2 HEAT ELEMENT DIMENSIONS................... 2-4 2.3 PAPER FEED CHARACTERISTICS ..................2-5 2.4 STEP MOTOR CHARACTERISTICS................... 2-6 2.4.1 Motor Drive Circuit....................2-7 2.4.2 Motor Timing......................2-9 2.4.3 Precautions for Driving the Motor................
  • Page 7 Section Page CHAPTER 3 CONNECTING EXTERNAL CIRCUITS 3.1 THERMAL HEAD CONTROL FPC ..................3-2 3.2 MOTOR/DETECTOR CONNECTOR..................3-4 CHAPTER 4 DRIVE METHOD 4.1 THERMAL HEAD DRIVE TIMING..................4-1 4.1.1 In case of executing previous line history control ............ 4-1 4.1.2 When previous line history control is not executed..........
  • Page 8 TABLES Table Page General Specifications ......................2-1 Sample Motor Drive Frequency................... 2-5 General Motor Specifications ....................2-6 Excitation Sequence......................2-8 Acceleration Steps ......................2-12 Blocks and Activated Heat Element .................. 2-15 Head Resistance Ranks....................2-16 Head Voltage........................2-17 Thermal Head Electrical Characteristics (at Vdd=5 V, 25°C)........... 2-18 2-10 Activation Pulse Width.......................
  • Page 9 Figure Page Example of motor drive timing chart in “High speed print mode”........4-6 Example of motor drive timing chart in “Standard print mode”........... 4-8 Curled Path......................... 5-2 Straight Path........................5-2 Sample Outer Casing Structure ..................5-4 LTP 3445 Appearance and External Dimensions............... 6-2 Guide Design Example .......................
  • Page 10 It can be used with a measuring instrument and analyzer, a POS, a communication device, or a data terminal device. Since the LTP3445 Line Thermal Printer Mechanism can be driven by battery, it can easily be mounted on a portable device such as a hand-held terminal.
  • Page 11 • Automatic paper load A paper detector enables the LTP3445 to load paper automatically. • Thermal head cleaning Moving the head open lever to the open position enables one to clean the thermal head. Print speed differs depending on working conditions.

  • Page 12: Specifications

    CHAPTER 2 SPECIFICATIONS 2.1 GENERAL SPECIFICATIONS Table 2-1 General Specifications Item Specification Print method Thermal dot line printing Dots per line 832 dots Resolution 8 dots/mm Print width 104 mm Maximum print speed 160 dot lines/sec (20 mm/sec) (at 5 V) 400 dot lines/sec (50 mm/sec) (at 7.2 V) Paper feed pitch 0.125 mm...
  • Page 13 Table 2-1 General Specifications (Continued) Item Specification Current consumption For driving the head (V Average 1.7 A (at 5 V), 2.5 A (at 7.2 V) Maximum 1.9 A (at 5 V), 2.8 A (at 7.2 V) For driving the motor (V Maximum 0.6 A For head logic (V Maximum 0.026 A...
  • Page 14 Table 2-1 General Specifications (Continued) Item Specification TF50KS-E2C (65 µm paper) Recommended thermal paper TF77KS-E2 (95 µm paper) TC98KS-T1 (125 µm paper) J & N tack HW74 (label paper) TW80KK-S (2-ply paper) from Nippon Paper Industries FH65BV-3 (65 µm paper) from Honshu Paper Co., Ltd.

  • Page 15: Heat Element Dimensions

    2.2 HEAT ELEMENT DIMENSIONS The LTP3445 contains a thermal head with 832 heat elements (dot-size). 104 mm (832 DOTS) 0.125 mm 0.125 mm Figure 2-1 Heat Element Dimensions mm (PAPER WIDTH) 4 mm 4 mm 104 mm (PRINTING WIDTH) 0.125 mm...

  • Page 16: Paper Feed Characteristics

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

  • Page 17: Step Motor Characteristics

    2.4 STEP MOTOR CHARACTERISTICS Table 2-3 General Motor Specifications Item Specification Type Number of phases 4-phase Drive method Bipolar Excitation 2-2 phase 11 Ω ± 7% Winding resistance per phase Rated voltage 4.2 - 8.5 V Rated current 0.3 A / phase Maximum current consumption 0.6 A Drive frequency...

  • Page 18: Motor Drive Circuit

    2.4.1 Motor Drive Circuit (1) Sample Drive Circuit A sample drive circuit for the motor is shown in Figure 2-3. Figure 2-3 Sample Drive Circuit (Motor)

  • Page 19: Excitation Sequence

    (2) Excitation Sequence As shown in Table 2-4, the LTP3445 feeds the 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 the reverse direction, drive the motor in the reverse order: step 4, step 3, step 2, step 1, step 4, step 3, .

  • Page 20: Motor Timing

    2.4.2 Motor Timing Refer to the time chart in Figure 2-5 when designing the control circuit or software for starting and stopping the motor. Also note the following precautions: Precautions for Designing the Motor Control Circuit and Software (1) Stop step •...
  • Page 21 (3) Other • Do not print paper at the 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. 2-10...

  • Page 22: Precautions For Driving The Motor

    2.4.3 Precautions for Driving the Motor (1) Motor Current Consumption Control The motor speed may slow down during printing depending upon the divided drive method, the printed contents and input data transmission speed during printing. At this time noises or over temperature of the motor may occur due to its over torque.

  • Page 23: Acceleration Steps

    (2) Acceleration Control When driving the motor, acceleration control is needed to get paper feed started. In the case that the motor is to be driven at the maximum motor drive frequency that was calculated using equation (1), the motor must be driven slowly at first to avoid slipping of the motor under the heavy load, resulting in the motor being out of step.

  • Page 24: Thermal Head

    2.5 THERMAL HEAD 2.5.1 Structure of the Thermal Head As Figure 2-7 shows, the LTP3445 thermal head consists of 832 heat elements, heat element drivers and preline history controllers. The preline history controller allows the preheat pulse to be applied to nonactivated elements on the preceding dot line before the main heat pulse.
  • Page 25 Block 13 Block 12 Block 1 dot832 dot769 dot768 dot705 dot64 dot2 dot1 Heat Element Output Driver Latch Register Shift Register HCLK Control IC HDAT LATCH CTRL BCLK BDAT BCLR Thermistor Figure 2-7 Thermal Head Block Diagram 2-14...

  • Page 26: Printed Position Of The Data

    DATA IN DATA PRINT SEQUENCE 1 2 3 4 5 6 ..830 831 832 LTP3445 PRINTER MECHANISM DATA INPUT SEQUENCE 1 2 3 4 5 6 ..830 831 832 Figure 2-8 Printed Position of the Data...

  • Page 27: Head Resistance

    2.5.3 Head Resistance The LTP3445 head resistance is classified into two ranks as shown in Table 2-7. Head resistance ranks are also indicated on the label on the front of the LTP3445. Table 2-7 Head Resistance Ranks Rank Head Resistance 162 to 178 Ω...

  • Page 28: Head Voltage

    2.5.4 Head Voltage The LTP3445 has a built-in head driver IC and control IC. Table 2-8 shows the head voltage. Table 2-8 Head Voltage Item Voltage Range Head drive voltage 4.2 to 8.5 V Head logic voltage 4.5 to 5.5 V 2.5.5 Peak Current...

  • Page 29: Thermal Head Electrical Characteristics

    2.5.6 Thermal Head Electrical Characteristics Table 2-9 Thermal Head Electrical Characteristics (at Vdd=5V, 25°C) Minimum Item Symbol Conditions Unit  Ω Head resistance  Head drive voltage Logic block voltage   Waiting for activation   Logic block current fclk=4MHz , HDAT=Fixed ...

  • Page 30: Timing Chart

    2.5.7 Timing Chart 1/fclk HCLK CTRL HDAT LATCH 1/fclk BCLK BDAT BCLR Figure 2-9 Timing Chart 2-19...

  • Page 31: Controlling The Head Activation (Dst) Pulse Width

    2.6.1 Calculation of the Head Activation Pulse Width The LTP3445 is provided with a preline history control function, allowing the preheat pulse to be applied to the nonactivated element on the preceding dot line before the main heat pulse. For actual drive method, refer to Section 4, “DRIVE METHOD”.

  • Page 32: Adjustment Of The Head Activation Voltage

    TC98KS-T1 (125 µm paper) J & N tack HW74 TW80KK-S (2-ply paper) TCC (2-ply paper) : Temperature coefficient 2-ply thermal paper 0.00448 Recommended thermal paper (except for 2-ply thermal paper) 0.00352 The thermistor resistance value at T (°C). Refer to Section 2.6.7. For driving for 2-ply thermal paper, refer to Section 2.6.8.

  • Page 33: Determination Of Activation Pause Time And Activation Pulse Period

    2.6.5 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 preceding activation start to current activation start) which conforms to equation (7) to reserve the pause time.

  • Page 34: Calculation Sample For The Head Activation Pulse Width

    2.6.7 Calculation Sample for the Head Activation Pulse Width Table 2-10 displays the calculation sample of the head activation pulse width that was calculated using equation (3) and the values obtained using equations (4) to (9). Table 2-10 Activation Pulse Width Head drive Thermistor Motor Drive Frequency (PPS)

  • Page 35: Thermistor Resistance

    2.6.8 Thermistor Resistance °C) is determined using the following The resistance of the thermistor at the operating temperature (T equation (10). Equation 10: × EXP B ×  -  273 + T Resistance at operating temperature Tx (°C) 15 kΩ ± 10% (25°C) 3750 K ±...
  • Page 36 Table 2-11 Temperature and Corresponding Thermistor Resistance Temperature Thermistor (° ° ° ° C) Resistance (kΩ) 47.49 37.09 29.23 23.22 18.59 15.00 12.19 9.97 8.21 6.80 5.66 4.74 4.00 3.38 2.88 2.46 2.11 1.82 1.58 1.37 1.19 2-25...

  • Page 37: How To Print Using 2-Ply Thermal Paper

    2.6.9 How to Print Using 2-ply Thermal Paper For fine printing, drive the thermal elements two times at half of the drive pulse that was calculated using equation (5) in Section 2.6.1. PRINTING TIME t ; HEAD DRIVE PULSE WIDTH (msec) 300µ...

  • Page 38: Head-Up Detector

    2.7 HEAD-UP DETECTOR LTP3445 has a built-in head-up detector to detect whether the head is up or down. This detector is a mechanical switch which is designed to close when the head is in the down position (printing state) and to open when in the up position.

  • Page 39: Paper Detector

    2.8 PAPER DETECTOR The LTP3445 has a built-in paper detector (reflection type photo-interrupter) to check for the presence or absence of paper. The external circuit should be designed so that it detects the output from the paper detector and does not activate the thermal head when paper runs out.
  • Page 40 Table 2-13 Paper Detector Input/Output Conditions Item Symbol Conditions Std. Max. LED (input) Forward voltage =20 mA 1.2 V 1.4 V Peak forward =0.5A 3.0 V 4.0 V voltage  10 µA Reverse current =6 V Capacity between =0 V, f=1 kHz 50 pF 100 pF terminals...

  • Page 41: Sample External Circuit

    2.8.2 Sample External Circuit PRINTER (5 V) (5 V) 100 kΩ Ω Ω Ω 200 Ω Ω Ω Ω PHOTO- INTERRUPTER 74HC04 TO CPU PORT 0.1 µ µ µ µ F The PS signal is high when paper is exhausted. Figure 2-13 Sample External Circuit of the Paper Detector 2-30...

  • Page 42: Automatic Paper Load

    2.8.3 Automatic Paper Load Paper can be automatically loaded when used in conjunction with the paper detector. To prevent paper from skewing, cut the edges at right angles with respect to the paper feed direction before loading it. If skewed, feed the paper until it is straight, or place the head in the up position and adjust the paper so that it is fed straight.
  • Page 43 2-32...

  • Page 44: Connecting External Circuits

    CHAPTER 3 CONNECTING EXTERNAL CIRCUITS The LTP3445 has a flexible printed wiring board (FPW) and a connector (510-21-09900 from Molex Co., Ltd.) used for connecting it to external circuits. Use the recommended connectors for connecting the external circuits as shown in Table 3-1.

  • Page 45: Thermal Head Control Fpc

    3.1 THERMAL HEAD CONTROL FPW Figure 3-1 shows the terminal configuration of the thermal head control FPW. Figure 3-1 Thermal Head Control Terminals (FPW)

  • Page 46: Thermal Head Control Terminal Assignments

    Table 3-2 Thermal Head Control Terminal Assignments Terminal Input/ Signal Name Function Number Output Input Thermal head drive voltage Input Thermal head drive voltage Input Thermal head drive voltage     Thermistor Input Thermal head print activation instruction signal Output Print data output BCLR...

  • Page 47: Motor/Detector Connector

    3.2 MOTOR/DETECTOR CONNECTOR Figure 3-2 shows the motor control terminals, paper detector terminals, and head-up detector terminals on the motor/detector connector. Figure 3-2 Terminals on the Motor/Detector Connector Table 3-3 Terminal Assignments of the Motor/Detector Connector Terminal Number Signal Name Function Motor drive signal Motor drive signal...

  • Page 48: Drive Method

    CHAPTER 4 DRIVE METHOD 4.1 THERMAL HEAD DRIVE TIMING 4.1.1 In case of executing previous line history control • Preface Input signals to the CTRL pin controls the driving of the previous line history control called pre-heat and main heat. BCLR should be normally “High”.
  • Page 49 Repeat the selection of the driving block, input of the pre-heat pulse and input of the main heat pulse to all blocks. Figure 4-1 shows the example of timing chart in case of executing previous line history control. When executing previous line history control, the pre-heat pulse data for the next line should not be transferred until the start of the last main heat driving of the previous line.

  • Page 50: When Previous Line History Control Is Not Executed

    4.1.2 When previous line history control is not executed • Preface CTRL is always set to “Low”. BCLR should be normally “High”. “Low” forcifully clears the selected block. • Input of print data Input of HDAT and HCLK transfer the print data to the shift register in serial input. “High”...
  • Page 51 Figure 4-2 shows an example of the timing chart when not executing previous line history control. When not executing previous line history control, the print data of the next line can be transferred immediately after storing it in the latch register. Figure 4-2 Example of timing chart when not executing previous line history control...

  • Page 52: Motor Drive Timing

    4.2 MOTOR DRIVE TIMING The phase of motors and the thermal head need to be synchronized to print. There are two driving modes, high speed print mode for high speed printing and standard print mode for high print quality. Select either of the two modes according to the application. Basic pulse width of the motor drive pulse, Tm, is a value (unit: msec) obtained by multiplying by 1000 the reciprocal number of the driving frequency calculated using formula 1 of “2.3 Paper Feed Characteristics”.
  • Page 53 Print the 1 line of data and transfer the next line of data in the same manner as the 1st line. Drive the motor by one step (4th step) regardless of whether DST is high or low after completing the 3rd step of the motor. The step time should be the next acceleration time of the 3rd step or Tm, whichever is longest.
  • Page 54 [Standard print mode] This driving method fixes the blocks printed in the 1st step and the 2nd step of each line. To give an example, the method will be described in which 1 line is divided into four groups, blocks 1 to 3, blocks 4 to 6, blocks 7 to 9 and block 10 to 13 and two groups are printed every one step of the motor.
  • Page 55 • 2nd line, 2nd step Drive the motor by one step (3rd step). The step time should be the acceleration time of next step nearest to the previous step taking time or Tm, whichever is longer. Drive blocks 7 to 9 and blocks 10 to 13 in the same manner as the 1st line, and transfer the next line data.

  • Page 56: Housing Design Guide

    The LTP3445 can be secured to the outer casing with screws. 5.1.1 Printer Mounting Method Secure the printer with 2 mounting holes (φ2.8) and 2 shaped indents. Refer to “Figure 6-1 LTP3445 Appearance” of “CHAPTER 6 APPEARANCE AND EXTERNAL DIMENSION” for the locations and dimensions. Recommended Screws and Washers...

  • Page 57: Layout Of Printer And Paper

    5.2 LAYOUT OF PRINTER AND PAPER The LTP3445 can be laid out as shown in Figure 5-2 or 5-3 according to the loading direction of the paper. When ordering, make your selection between the two models based on the desired use.

  • Page 58: Where To Mount The Paper Holder

    5.3 WHERE TO MOUNT THE PAPER HOLDER When determining the layout of paper holder, note the following: • When you use a paper roll, set the holder so that the paper is in alignment with the paper intake with no horizontal offset, and that the center axis of the paper roll is parallel with the printer. •...

  • Page 59: Outer Casing Structure

    5.5 OUTER CASING STRUCTURE Figure 5-4 shows a sample structure for the outer casing. Provide a gap of a few mm between the printer and the outer casing since the area over the thermal head becomes very hot. Figure 5-4 Sample Outer Casing Structure...

  • Page 60: Appearance And Dimensions

    CHAPTER 6 APPEARANCE AND DIMENSIONS Figure 6-1 shows the appearance and external dimensions of the LTP3445.
  • Page 61 Figure 6-1 LTP3445 Appearance and Dimensions...

  • Page 62: Safety Precautions

    CHAPTER 7 SAFETY PRECAUTIONS To use the printer safely, design the product with observing the following precautions. Additionally, caution users by describing some directions in the instruction manual or paste the caution labels on the product, if necessary. 7.1 DESIGN PRECAUTIONS •...

  • Page 63: Battery Driving

    7.2 BATTERY DRIVING • Precautions for battery drive As with any battery, there is always a danger of some mishap occurring from an overheating or bursting of the battery through over-discharge. Observe the precautions of the battery to be used.

  • Page 64: Designing And Handling Precautions

    CHAPTER 8 DESIGNING AND HANDLING PRECAUTIONS To maintain the initial level of performance of the LTP3445 and to prevent future problems from occurring, observe the following precautions. 8.1 DESIGN PRECAUTIONS Do not apply an energy source that is too high.

  • Page 65: Handling Precautions

    8.2 HANDLING PRECAUTIONS If any paper other than that specified is used, high print quality and long life of the thermal head cannot be guaranteed. Possible problems that may occur: • Poor print quality due to low-sensitivity paper • Abrasion of the thermal head due to paper surface which is too rough •...

  • Page 66: Loading/Unloading Paper Precautions

    8.3 LOADING/UNLOADING PAPER PRECAUTIONS Loading paper • Load paper with the thermal head in the up position. (See Figure 8-1 Head Cleaning Procedure (b) in Section 8.4 “HEAD CLEANING PROCEDURES AND PRECAUTIONS”). • Cut the edge of the paper so that the center of the paper will be inserted first NO GOOD NO GOOD NO GOOD...
  • Page 67 Automatic paper load • Assemble the guide in a position that contacts the side edge and back side of the paper so the paper can be inserted smoothly. The guide should be assembled away from the printer for 1 mm or less.

  • Page 68: Head Cleaning Procedure And Precautions

    8.4 HEAD CLEANING PROCEDURE AND PRECAUTIONS PROCEDURE : Lift the head open lever (a) so it stands upright (b). Push the head open lever into the opening in the back of the frame, rolling the head up (c), and latch it. Clean the heat elements using alcohol and a cotton swab.

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