Sharp DP-750 Service Manual
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Sharp DP-750 Service Manual

Sharp DP-750 Service Manual

Sharp serial dot matrix printer service manual
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CHAPTER 1. Printer Handling and Maintenance ............................................. 1
CHAPTER 2. Specifications and Operation Principles ..................................... 2
CHAPTER 3. Disassembly and Assembly ..................................................... 10
CHAPTER 4. Troubleshooting........................................................................ 29
PARTS GUIDE (PRINTER ASSEMBLY : KI-OB2014RC01)
APPLICATION MODEL : UP-600 ("U" & "A" version)
Parts marked with "
" are important for maintaining the safety of the set. Be sure to replace these parts with specified
ones for maintaining the safety and performance of the set.

SERVICE MANUAL

Serial Dot Matrix
Printer
MODEL
CONTENTS
SHARP CORPORATION
DP-750
This document has been published to be used
for after sales service only.
The contents are subject to change without notice.

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Summary of Contents for Sharp DP-750

  • Page 1: Service Manual

    SERVICE MANUAL Serial Dot Matrix Printer DP-750 MODEL CONTENTS CHAPTER 1. Printer Handling and Maintenance ..........1 CHAPTER 2. Specifications and Operation Principles ........2 CHAPTER 3. Disassembly and Assembly ............. 10 CHAPTER 4. Troubleshooting................ 29 PARTS GUIDE (PRINTER ASSEMBLY : KI-OB2014RC01) APPLICATION MODEL : UP-600 ("U"...

  • Page 2: Table Of Contents

    Symbol/PartsCod) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - INTRODUCTION This manual explains the operation principles and servicing procedures for the Citizen dot matrix printer DP750 series.

  • Page 3: Chapter 1. Printer Handling And Maintenance

    CHAPTER 1. Printer Handling and Maintenance (1) If printer paper other than the recommended (7) Removing paper paper is used, print quality and service life Remove the paper only after printer operation cannot be guaranteed. has ceased. Pull the paper straight out in the same direction Make sure that the paper width and quality are within specifications.

  • Page 4: Chapter 2. Specifications And Operation Principles

    CHAPTER 2 . Specifications and Operation Principles 2-1 General Specifications Rating Item Remarks Printing method Serial impact dot matrix printer Printing direction Bi-directional printing Approx. 3.0 lines/second m10% Printing speed ˚ 24.0 V DC, 25 C, continuous printing Receipt side: 108 dots/216 positions Total number of dots Journal side: 108 dots/216 positions Validation: 248 dots/495 positions...
  • Page 5 Item Rating Remarks Printer paper Roll paper Width: 44.5 0.5 mm, outer diameter: max. Ø 83 mm 135 - 210 mm (W) x min. 70 mm (H) Single-line validation Validation paper Take-up device Built-in Connection principle Pin connector Service life Mechanism MCBF 4 million lines, maximum 8 million lines Head...

  • Page 6: Mechanism Outline

    2-3-2 Sensor Assembly 2-2 Mechanism Outline The sensor assembly is comprised of 3 sensors; The mechanism of this printer can be divided the dot pulse sensor (DP), home position sensor into 9 blocks. (HP) and reset pulse sensor (RP). • Drive force transmission assembly •...

  • Page 7: Print Head Assembly

    (2) Head drive assembly Head assembly Carriage Carriage drive pulley Timing belt assembly Carriage drive pulley Carriage drive gear 2-3-3 Print Head Assembly Bevel gear 2 Bevel gear 1 (1) Print control Printing is carried out by the print head comprising of 9 solenoids and moving from left to right.

  • Page 8: Paper Feed Assembly

    2-3-4 Paper Feed Assembly 2-3-5 Ribbon Cassette Assembly (1) Paper feed mechanism (1) Ribbon cassette feed mechanism Ribbon cassette PF latches Pressure rollers Worm wheel PF roller Ribbon drive shaft assembly PF solenoid assembly PF gear PF armature Ribbon drive gear Idling gear 2 Reduction gear 1...

  • Page 9: Paper Take-Up Assembly

    2-3-6 Paper Take-up Assembly (3) Take-up mechanism types (1) Paper take-up mechanism Spool Spool gear Type which is the same height as the main unit Winder timing belt Idle gear 2 Winder pulleys Spool holder assembly Type which is lower than the height of the main unit (2) Near-end detection mechanism Roll paper Roll paper core...

  • Page 10: Connectors

    2-4 Connectors 2-4-2 Terminal Functions 2-4-1 Terminal Layout Terminal name Function Connector type Printer side: Molex 5342-30T2 Print solenoid #3 Host side: Molex 5320-30AT2 VM COM. Motor (-) VM COM. Pin arrangement diagram Print solenoid #7 Motor on/off signal Print solenoid COM. Home position sensor output Print solenoid COM.

  • Page 11: Terminal Circuit Diagram

    2-4-3 Terminal Circuit Diagram Print solenoid #3 Motor (-) 24 V GND Print solenoid #7 Motor ON/OFF signal Print solenoid COM. (VS) H.P. (home position pulse) Print solenoid COM. (VS) D.P. (dot pulse) Print solenoid #5 Motor (+) (+24 V) Print solenoid #2 (reserved) Print solenoid #1...

  • Page 12: Chapter 3. Disassembly And Assembly

    CHAPTER 3. Disassembly and Assembly Please observe the following precautions when (1) Screw nuts on fastening screws (M3x10 hex socket performing maintenance. screws) and insert screws into paper guide (U). Make sure that nuts fit snugly into V-shaped cutouts on Note paper guide (U).
  • Page 13 (3) Fit PF housing with mounted platen assembly into paper guide (U) and fasten it with fastening screws (A) (M3x6) and other fastening screw (M3x8). Note: 1. When performing assembly procedures, PF clutch spring 2 push the PF housing down until it is secured by the four hooks on the paper guide (U).
  • Page 14 (10) Mount the PF latch 2 onto PF shaft from the receipt (12) Insert the PF shaft assembly into the PF housing side, and the PF roller assembly from the journal side. and apply ORELUBE G-1/3 to the left and right fixing lever (L)and (R).
  • Page 15 (13) Mount fixing levers (L) and (R) and PF gear on to (17) Apply FLOIL G-337 to the PF armature tip. Then the PF shaft assembly, and fasten with E-rings (E4). mount the PF solenoid assembly to the PF housing (14) Attach the fixing lever spring to fixing levers (L) and fasten it with fixing screws (M3x8).
  • Page 16 (19) Install four paper side guide plates on the bottom (23) Apply ORELUBE G-1/3 to the pivot of the main of paper guide (U). frame assembly. Mount the carriage drive gear and carriage drive pulley and fasten with E-ring (E2.5). E-ring Carriage drive gear Carriage drive pulley...
  • Page 17 (24) Apply ORELUBE G-1/3 to the pivot of the pulley (28) Apply ORELUBE G-1/3 to the fastening boss of the drive assembly. Mount the carriage drive pulley and stamp lever plate in the paper guide (L) assembly and fasten with E-ring (E2.5). to the three slits contacting the plate.
  • Page 18 (30) Mount the motor assembly and motor spacer on to the right side of the main frame assembly and fasten with fastening screws (M3x5). Note: Mount the motor so that the lead wires are on the bottom side. Motor assembly E-ring Motor spacer Main frame...
  • Page 19 (35) Apply ORELUBE G-1/3 to the four pivots on the Bevel gear 2 Reduction gear 4 assembly frame (R) support plate assembly and on the ribbon Rear cushion Reduction gear 2 drive shaft mount hole. E-ring Apply ORELUBE G-1/3 Washer Reduction gear 1 Frame (R) support plate assembly...
  • Page 20 (42) Pull the winder timing belt onto the winder pulley Rear cushion assembly. (43) Install the frame (R) support plate assembly on to the main frame assembly and fasten with fastening screws (M3x8). Winder pulley assembly Main frame Winder assembly timing belt Frame (R) support plate assembly...
  • Page 21 (52) Mount the felt on the carriage and install in the main frame assembly with the carriage shaft inserted from the left side. Note: 1. Moisten the felt with Mobile 1. Fastening 2. When installing, start from a position screw Boss (There is a boss in the where the carriage drive pin is parallel to...
  • Page 22 (57) Place the insulating sheet and transistor on the main PCB assembly, and fasten with the fastening screw (M3x10). Note: When installing, bend the transistor legs at a right angle, in alignment with the soldering holes on PCB. (58) Screw the nut (M3) on to the fastening screw (M3x10) and fasten the FFC fixer plate.
  • Page 23 (61) Loosen the fastening screw of the frame (R) support plate assembly and engage the winder timing belt Head cable Head assembly on the winder pulley of the winder assembly. Then Cable engage the winder assembly boss in the main frame fixing sheet assembly hole, and fasten with fastening screws (M3x6).
  • Page 24 (65) Insert the ribbon plate spring in the ribbon plate (68) Install the grounding spring in the PF housing assembly. assembly and the main frame assembly front center. (66) Mount the head cover on the main frame assembly Note: 1. Insert the grounding spring between the and fasten with fastening screws (M3x5).

  • Page 25: Adjustment

    (69) Install the 2-station housing cover on the PF housing 3-4 Adjustment assembly and fasten with fastening screws (M3x8). There are six adjustment items for this printer, as listed below. Perform the adjustments in the listed Fastening screw order. 2-station housing cover (1) Print speed adjustment (2) Platen/head gap adjustment...

  • Page 26: Platen/Head Gap Adjustment

    (3) Adjustment 3-4-3 Bi-directional Printing Shift Adjustment Adjust the print speed adjustment VR on the (1) Procedure solder side of the main PCB assembly until cycle Perform bidirectional printing. Judge the results A falls within the range shown below. and rotate the motor shaft while holding the timing disc stationary, until there is no printing Value of A Adjustment procedure...

  • Page 27: Rp/Hp Waveform Check

    3-4-4 RP/HP Waveform Check (1) Procedure Perform bi-directional printing and use an oscilloscope to measure the phase shift A between the reset pulse (RP) waveform and home position pulse (HP) waveform. (2) Check points RP waveform: Connector pin 26 HP waveform: Connector pin 6 GND: Connector pin 24 (3) Adjustment...

  • Page 28: Head Assembly Replacement

    3-5 Head Assembly Replacement Head cover 3-5-1 Disassembly Procedure Fastening (1) Remove printer from the POS/ECR. screw (2) Remove the ribbon cassette. (3) Push the right and left fixing lever and open the PF housing assembly. Ribbon cassette Fastening screw PF housing assembly (5) Move the ribbon plate as follows.

  • Page 29: Assembly Procedure

    3-5-2 Assembly Procedure Ribbon plate (1) Plug the head cable into the head assembly connector. Note: Make sure that the head cable is pushed Fastening screw fully into the connector. (2) Insert the head assembly into the carriage guide. Just before the assembly is fully seated, push the bent section of the head cable into the carriage slit.
  • Page 30 (5) Reinstall the ribbon plate by reversing the disassembly procedure. Protrusion Note: Make sure that ribbon plate fastening screw section is on the inside of the main Main frame assembly frame assembly. Fastening screw Head cover Ribbon plate Fastening section Fastening screw Fastening...

  • Page 31: Chapter 4. Troubleshooting

    Head movement problem...
  • Page 32 Head movement problem Print problem...
  • Page 33 Print problem Paper feed problem...
  • Page 34 Paper feed problem Ribbon feed problem...
  • Page 35 DP-750 Parts guide 1 Mechanism etc No.1 PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK 1 0 C Z C 3 4 0 1 - 6 3 7 / Transistor (2SD1637) 2 0 C Z E 1 1 1 3 0 - 0 5 /...
  • Page 36 DP-750 1 Mechanism etc No.1 52 41 RCP00390 – 2 –...
  • Page 37 DP-750 2 Mechanism etc No.2 PRICE PART PARTS CODE DESCRIPTION RANK MARK RANK 3 0 C Z E 1 1 1 3 0 - 0 6 D Screw (PHT(ST),M3 6) 4 0 C Z E 1 1 2 3 0 - 0 6 U...
  • Page 38 DP-750 2 Mechanism etc No.2 40 9 RCP003901 – 4 –...
  • Page 39 COPYRIGHT 2001 BY SHARP CORPORATION All rights reserved. Printed in Japan. No part of this publication may be reproduced, stored in a retrieval system, or transmitted. In any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.

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