Oki ML620 Maintenance Manual
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Oki ML620 Maintenance Manual

Oki ML620 Maintenance Manual

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ML620/ML621
Maintenance Manual
020711B
Oki Data CONFIDENTIAL

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  • Page 1 ML620/ML621 Maintenance Manual 020711B Oki Data CONFIDENTIAL...
  • Page 2 Please refer to the "Illustrated Parts Manual" for spare part information.
  • Page 3 Nothing contained herein shall be construed as conferring by estoppel, implication or otherwise any license or right under any patent or trademark of Oki Data, Oki Electric Industry Co., Ltd. ("Oki Electric"), or any third party. Except as provided above nothing contained herein shall be construed as conferring any license or right under any Oki Data copyright.

  • Page 4: Table Of Contents

    Oki Data CONFIDENTIAL Contents 1. CONFIGURATION ....................6 Standard Printer Configuration .................... 6 Options ..........................7 2. THEORY OF OPERATION ..................9 Electrical Operation ......................9 2.1.1 Summary ......................... 9 2.1.2 SOC and the Peripheral Circuit ................9 2.1.3 Initialization ......................12 2.1.4...
  • Page 5 Oki Data CONFIDENTIAL 3.3.20 Control Board, ACF Board, Motor Fan ..............75 3.3.21 Power supply UNIT (BOARD) ................77 3.3.22 Front-Roller-Feed ....................78 4. ADJUSTMENT ....................79 5. CLEANING AND LUBRICATION ...............88 Cleaning ..........................88 Lubrication ......................... 89 6. TROUBLESHOOTING AND REPAIR ..............100 Items to Check Before Repair ..................

  • Page 6: Configuration

    Oki Data CONFIDENTIAL CONFIGURATION Standard Printer Configuration This printer consists of the following assemblies: heet guide Access cover Tractor Guide-Pull-up Pull up Ribbon Platen knob Front sheet guide Printer Figure 1-1 Configuration 44209901TH Rev.2...

  • Page 7: Options

    Oki Data CONFIDENTIAL Options Cut sheet feeder unit (CSF) (Narrow and wide versions available) Single-bin CSF Roll paper stand (Narrow only) RS232C Serial interface board 44209901TH Rev.2...
  • Page 8 Oki Data CONFIDENTIAL OKI LAN board 44209901TH Rev.2...

  • Page 9: Theory Of Operation

    • Built-in CPU core (ARM7TDMI) • SPAM 4M bit • With built-in USB controller • With built-in UART function • AD converter x 4ch DA converter x 2ch OKI of other peripheral circuitry is original though CPU core uses ARM7TDMI. 44209901TH Rev.2...
  • Page 10 Oki Data CONFIDENTIAL OPTION CSF or 48Mhz ROLL PAPER STAND ADDRESS FLASH OPERATION BOARD DATA RESET-N HEAD ALARM ALARM-P CIRCUIT HD TEMP PRINT HEAD DRIVE HEAD PARARREL CIRCUIT IEEE1284 DERIVER IC EEPROM OPTION I/F FUSE RS232C DRIVER HOME POSITION MOTOR...
  • Page 11 Oki Data CONFIDENTIAL Program ROM (external FLASH ROM) The program to make the printer work is stored in FLASH ROM as external ROM. FLASH ROM that can be installed is 64Mbit(16 x 4096k) or less. The access timing of the outline to FLASH ROM is shown in the following.

  • Page 12: Initialization

    Oki Data CONFIDENTIAL 2.1.3 Initialization This printer is initialized when the power is turned on or when the I-PRIME-N signal is input from the host side via the parallel interface. For the initialize operation, the RST-N signal is first output from the reset circuit to reset the SOC and Flash ROM.

  • Page 13: Interface Control

    Oki Data CONFIDENTIAL 2.1.4 Interface Control Parallel Interface The parallel data input from the host to the interfaced LSI is latched to its internal register at the falling edge of the STROBE-N signal. At the same time, the LSI sets the BUSY signal to the high level to inform the host that the data is being processed, and outputs the RXD signal to inform the MPU of data reception.
  • Page 14 Oki Data CONFIDENTIAL Universal Serial Bus (USB) Universal Serial Bus Specification Revision 2.0 (Full speed) compliance. Connector • Printer Side : “B” Receptacle (Upstream Input to the USB Device) • Cable Side : Series “B” Plug Cable • Cable Length : Approx 1.8m (A cable must be met USB Spec Rev 1.1 for...
  • Page 15 Oki Data CONFIDENTIAL Signal Level • Input / Output Level Parameter Symbol Min. Max. Units Input Levels : High (driven) High (floating) Output Levels : High (driven) Output Signal Crossover Voltage 15 / 44209901TH Rev.2...

  • Page 16: Print Control

    Oki Data CONFIDENTIAL 2.1.5 Print Control Print data is transmitted as parallel data (HD01~HD18) from SOC to print head. SOC generates print timing and drive time. Control Board Print Head DRIVER Print Data Print Data HD01-P~ HEAD1-N~ HD18-P HEAD18-N HEAD DRIVE TIMING CHART...
  • Page 17 Oki Data CONFIDENTIAL Print Compensation Control The print compensation can be made as shown below: Voltage compensation (See 2.1.8 “Alarm Circuit.”) Temperature compensation (See 2.1.8 “Alarm Circuit.”) Pin stroke compensation Platen Print Head Pin 1, 2 As shown in the drawing left, the stroke length up to the platen is different for each pin.

  • Page 18: Sp/Lf/Rbn/Main Fan Control

    Oki Data CONFIDENTIAL 2.1.6 SP/LF/RBN/MAIN FAN CONTROL The driver of each motor is controlled according to the control signal from SOC and the motor is driven. (1) SP MOTOR CONTROL The motor that uses it is a hybrid type stepping motor.
  • Page 19 Oki Data CONFIDENTIAL (3) RIBBON MOTOR CONTROL The motor that uses it is PM type stepping motor. The outline circuit composition : as shown in the following figures. RBNSTEP-P Driver OUT1A OUT1B OUT2A RBNENB-N OUT2B RBNPULLIN-P SENSE1 SENSE2 RIBBON Motor...

  • Page 20: Operation Panel

    Oki Data CONFIDENTIAL 2.1.7 OPERATION PANEL OPERATION PANEL is controlled by each signal port of SOC. An outline circuitry is as follows. OPERATION PANEL OP1board PRINT PEED LF/FF W7ON-N~ W4ON-N TEAR W1_3ON-N CHARACTER PICH LOAD/EJECT 7.5k(F) 2k(F) 3.9k(F) PRINT CUALITY...

  • Page 21: Alarm Circuit

    Oki Data CONFIDENTIAL 2.1.8 Alarm Circuit Head drive time alarm circuit This circuit monitors the drive time using the DT1ALM1-N signal interlocked with the overdrive signal of each drive circuit. If the drive time of any drive circuit exceeds the specified time, the drive fault alarm circuit sends an ALM-P signal to POWER SUPPLY UNIT.
  • Page 22 Oki Data CONFIDENTIAL Overheat alarm Head overheat alarm The voltage of the output HTEMP signal of the thermistors, one of which is contained in the print head is monitored by the A/D port of the SOC to control the voltage.

  • Page 23: Power Supply Unit

    Oki Data CONFIDENTIAL 2.1.9 Power Supply Unit This power supply unit is a switching power supply. This power supply unit supplies the +5VDC, +40VDC. C Fuse Electric Filter +40VDC current circuit circuit circuit control +5VDC circuit circuit larm LM-P circuit...

  • Page 24: Motor/Fan/Aluminum Electrolytic Capacitors

    Oki Data CONFIDENTIAL (4) Alarm function (See 2.1.8) When an ALM-P signal has been output from the control unit, this function suspends switching and cuts off all output. This state is maintained after the power switch is turned off until the power supply resumes about 30 seconds later.

  • Page 25: Mechanical Operation

    Oki Data CONFIDENTIAL Mechanical Operation 2.1.1 Printhead Mechanism and Operation (See Figure 2-2.) The printhead is a spring charged 9 double-pin driving head using a permanent magnet. It is attached to the carriage, which moves in parallel with the platen. Electrically, this unit is connected to the control circuits through the control board.
  • Page 26 Oki Data CONFIDENTIAL Operation of printhead (See Figure 2-3.) When the printhead is idle, the armature is attracted by a permanent magnet and the spring fixing the armature is compressed. The print wires fixed to each armature are thus concealed under the wire guide.
  • Page 27 Oki Data CONFIDENTIAL Paper Printhead Print wire Platen When printing Paper Armature assembly Thermistor Print wire Wire guide Yoke Magnet assembly Spacer When not printing Paper Figure 2-3 27 / 44209901TH Rev.2...

  • Page 28: Spacing Operation (See Figure 2-4.)

    Oki Data CONFIDENTIAL 2.2.2 Spacing Operation (See Figure 2-4.) The spacing mechanism consists of a carriage shaft mounted in parallel with the platen, and a carriage frame that moves along the shaft. Items included in the spacing mechanism are as follows: The space mechanism is driven by a stepping motor located behind the carriage frame.

  • Page 29: Head Gap Adjusting (See Figure 2-5.)

    Oki Data CONFIDENTIAL 2.2.3 Head Gap Adjusting (See Figure 2-5.) The head gap adjusting lever moves back and forth to tilt the carriage frame, altering the gap between the printhead and the platen. Being rotated, both ends of the carriage shaft are eccentric, the shaft moving toward or away from tha platen.

  • Page 30: Ribbon Drive (See Figure 2-6.)

    Oki Data CONFIDENTIAL 2.2.4 Ribbon Drive (See Figure 2-6.) The ribbon driver mechanism moves the ribbon by the ribbon motor operation. The ribbon drive mechanism consist of the following items: Ribbon feed gear assembly Ribbon cartridge Ribbon cartridge An endless ribbon with a single direction feed is used. Ink is supplied from an ink tank, which is built in to the ribbon cartridge.

  • Page 31: Paper Feed Operation

    Oki Data CONFIDENTIAL 2.2.5 Paper Feed Operation Feeding of the paper is performed by turning the platen and the pin tractor, which is driven by the LF pulse motor. Item of the paper feed mechanism are as follows: Pulse motor with gears...
  • Page 32 Oki Data CONFIDENTIAL Cut sheet and continuous sheet switching mechanism (See Figure 2-7.) Five (wide four) different paper paths can be selected and set by the change lever. (for cut sheet) When the cut sheet is used in the manual mode or fed by the CSF (option), set the...
  • Page 33 Oki Data CONFIDENTIAL Correlation in Mechanism Mechanism Gear Gear Rear Bottom Front Sheet Gear Idle A Change A Change B Lever Switch Switch Insertion Position Manual/ Rear route automatic Rotate Stop Stop CSF: Operation SW Bottom route or instruction •...
  • Page 34 Oki Data CONFIDENTIAL Position change lever Release shaft Release lever Control board Release shaft gear PULL FRONT REAR ear Idle A Rear Posision Front Posision ear Idle A ear Change ear Change Figure 2-7 34 / 44209901TH Rev.2...
  • Page 35 Oki Data CONFIDENTIAL Cut-sheet feeder operation (See Figure 2-8.) The pulse motor used for the paper feed mechanism is mounted on the left of the frame, and the rotation of the motor is transmitted through decelerating gears (Gear LF Idle, Gear Platen L) to the platen.
  • Page 36 Oki Data CONFIDENTIAL Continuous paper feed operation (Rear) (See Figure 2-9.) The force transmitted to Gear LF Idle, rotates the Gear Tractor through Gear Idle A and the Gear Change. The rotation of the Gear Tractor makes the pin tractor belt rotate through a sheet feeder shaft, feeding the continuous paper.
  • Page 37 Oki Data CONFIDENTIAL Continuous paper feed operation (FRONT)(See Figure 2-10.) The force that is transmitted to the Gear-LF-Idle rotates the Gear Tractor through the gears of Gear Idle A, Gear Change, Gear Idle A, Gear Idle C, Gear Idle B and Gear Idle C. The rotation of the Gear Tractor makes the pin tractor belt rotate through a sheet feeder shaft, feeding the continuous paper.
  • Page 38 Oki Data CONFIDENTIAL Cut-sheet feeder operation (FRONT)(See Figure 2-11.) The force that is transmitted to the Gear LF Idle rotates both the platen through the Gear Platen L and the Roller shaft through the Gear Idle B and the Gear Feed.
  • Page 39 Oki Data CONFIDENTIAL Pull tractor mechanism (See Figure 2-12.) The rotation of the Gear LF Idle is transmitted to the Gear Idle A of the pull tractor unit through the Gear Platen at the right end of the platen. The rotation of the Gear LF Idle...
  • Page 40 Oki Data CONFIDENTIAL Push and pull tractor mechanism (Option) (See Figure 2-13) This mechanism consist of two pull tractor mechanism. This mechanism can perform foward and reverse feed by setting continuous sheets to the push tractor and pull tractor. The rotation of the Gear LF Idle A is transmitted to the push tractor and the pull tractor.
  • Page 41 Oki Data CONFIDENTIAL Cut-sheet feeder unit operation (option)(See Figure 2-14.) To install a CSF, remove the Pull-Tractor-Attachment-L and the Pull-Tractor-Attachment- R from the Frame-side-(L)-outsert and the Frame-size-(R)-outsert respectively. The force of the Gear LF Idle is transmitted to the platen though the Gear LF Idle and the Gear Platen L.
  • Page 42 Oki Data CONFIDENTIAL Roll paper stand mechanism (option)(See Figure 2-15.) The Roll paper stand is attached on the Sheet Guide Assy. Rear. The force of the Gear LF Idle is transmitted to the Gear Platen L through the Gear LF Idle and rotates the platen.
  • Page 43 Oki Data CONFIDENTIAL (10) Paper clamp mechanism (See Figure 2-16.) When setting the change lever to the PULL , or REAR , RPS , FRONT position, the Shaft-Release rotates causing the Frame-Roller to move up/down to determine the position of the Roller-Pressure.
  • Page 44 Oki Data CONFIDENTIAL Cut (Rear) Position erease shaft oller frame RPS Position (Narrow only) ear pressure roller Figure 2-16-1 44 / 44209901TH Rev.2...
  • Page 45 Oki Data CONFIDENTIAL Rear Push Position Front Push Position Pull Position Figure 2-16-2 45 / 44209901TH Rev.2...

  • Page 46: Paper Detection Mechanism (See Figure 2-17.)

    Oki Data CONFIDENTIAL 2.2.6 Paper Detection Mechanism (See Figure 2-17.) Cut sheet, rear sheet detection When a cut sheet or continuous sheet is feed from the rear side between the platen and the Paper Pan Lower, the Lever paper end (Rear) Point A moves down, the lever moves out of the photo sensor's path, and then the rear feed is detected.
  • Page 47 Oki Data CONFIDENTIAL Top line print mechanism (See Figure 2-19.) The front edge of the sheet is protected by the ribbon protector so that it can stop at a position just near to the print head (0 tear off position) to start printing at the front end of the sheet, without causing the sheet to crumple or curl up.

  • Page 48: Automatic Sheet Feed

    Oki Data CONFIDENTIAL 2.2.7 Automatic Sheet Feed This function is used to feed in the sheet automatically up to the print start position when the cut sheet or the continuous sheet is used. [Operational procedure] When using the cut sheet Set the change lever to the CUT SHEET position.
  • Page 49 Oki Data CONFIDENTIAL When using the continouos paper Set the change lever either to the rear side, front side or the pull side position. (See Figure 2-20.) Set a sheet of paper either to the push tractor. Press the “LOAD/EJECT” switch.

  • Page 50: Paper Park Function (Continuous Paper)

    Oki Data CONFIDENTIAL 2.2.8 Paper Park Function (Continuous paper) Continuous sheets which have been inserted can be reversed automatically by using the “LOAD/ EJECT” button on the operation panel. Press the “LOAD/EJECT” button on the operation panel. Reverse LF is started and paper is fed in reverse until paper end occurs or 14 inches maximum have been fed.

  • Page 51: Assembly/Disassembly

    Oki Data CONFIDENTIAL ASSEMBLY/DISASSEMBLY This section explains the procedures for removing and installing various assemblies and units in the field. Description is mainly limited to the removal procedure; installation should basically be performed in the reverse sequence of the removal procedure.

  • Page 52: Service Tools

    Oki Data CONFIDENTIAL Service Tools Table 3.1 lists the tools necessary for replacing printed circuit boards and parts of units in the field. Table 3.1 Service tools Service Tool Q’ty Remarks No. 2-200 Phillips Screws screwdriver 3-5 mm No. 3-100...

  • Page 53: Disassembly/Reassembly Procedure

    Oki Data CONFIDENTIAL Disassembly/Reassembly Procedure This section explains the assembly replacement procedures according to the following disas- sembly system. [Parts Layout] Sheet guide assy Tractor assy Guide pull up Operation panel board Upper cover assy Pull-up roller Assy Fan cover...
  • Page 54 Oki Data CONFIDENTIAL [How to Change Parts] This section explains how to change parts and assemblies appearing in the disassembly diagram below. Printer unit 3.3.1 Printhead 3.3.2 Ribbon protector 3.3.3 Pull-up roller Assy 3.3.4 Upper Cover, Access Cover Assy and sheet Guid Assy, Tractor Assy 3.3.5...

  • Page 55: Printhead

    Oki Data CONFIDENTIAL 3.3.1 Printhead Open the access cover 1. Move carriage frame to lack of a pull-up cover 2. Remove the one screw 3, and then the fan cover 4. Pull up and rotate the head clamp 5 to unclamp the printhead 6 as shown Figure 3.3.1.

  • Page 56: Ribbon Protector

    Oki Data CONFIDENTIAL 3.3.2 Ribbon Protector Remove the printhead. (See 3.3.1) Open the pull-up roller cover 1. Raise and remove the ribbon protector 2. To install, follow the removal steps in the reverse order. Notes : After installation, check the slice level. (See 4-6) Cautions after replacement: Set the slice level for the edge sensor, with no paper fed into the printer.

  • Page 57: Pull-Up Roller Assy

    Oki Data CONFIDENTIAL 3.3.3 Pull-up Roller Assy Open the access cover 1. Lift up the sheet guide Assy 2 to remove. Remove the Guide-Pull-Up 3. Tilting the pull-up roller Assy 4 toward the rear, remove from the shaft of frame 5.

  • Page 58: Upper Cover Assy, Access Cover Assy And Sheet Guide Assy, Tractor Assy

    Oki Data CONFIDENTIAL 3.3.4 Upper Cover Assy, Access Cover Assy and Sheet Guide Assy, Tractor Assy Pull off the platen knob 1. Turn the change lever 2 toward the rear position. Open the access cover Assy 3 toward the front to remove.

  • Page 59: Platen Assy

    Oki Data CONFIDENTIAL 3.3.5 Platen Assy Remove the printhead. (See 3.3.1) Remove the ribbon protector. (See 3.3.2) Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.1 (1) – (6)) Turn the change lever 1 to the cut position.

  • Page 60: Printer Unit

    Oki Data CONFIDENTIAL 3.3.6 Printer unit Remove the Pull-up Roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the four screws 1 and remove the Plate-Shield-Upper 2. Remove the two screws 3 and remove the Bracket-Side-R 4, the Bracket-Side-L 5 from the Cover-Lower.

  • Page 61: Carriage Cable

    Oki Data CONFIDENTIAL 3.3.7 Carriage Cable Remove the Pull-up roller Assy. (See 3.3.1) Remove the Upper cover. (See 3.3.4) Remove the four screws 1 and remove the Plate-Shield-Upper 2. Remove the Printehead. (See 3.3.1) Slide the Clamp-Head-Cable 3 to the left by pressing the round tab on it and pull the cable down to remove.

  • Page 62: Homing Sensor

    Oki Data CONFIDENTIAL 3.3.8 Homing sensor Remove the Pull-up roller Assy. (See 3.3.1) Remove the Upper cover. (See 3.3.4) Remove the Plate-Shield-Upper. (four screws) (See 3.3.7) Slide the Clamp-Home-Sensor 1 to the left by pressing the round tab on it and pull the clamp down to remove.

  • Page 63: Idle-Pulley

    Oki Data CONFIDENTIAL 3.3.9 Idle-pulley Remove the Pull-up Roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the locking screw 1 of the idle pulley bracket 2. Remove the plate tension spring 3. Remove the pitch belt 4 from the pulley on the space motor side.

  • Page 64: Ribbon Feed Assy. (Ribbon Motor)

    Oki Data CONFIDENTIAL 3.3.10 Ribbon Feed Assy. (ribbon motor) Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) From the Cover-Motor 1, disconnect the Motor-SP-Cable, Head-Cord, Operation-Panel- Cable, Motor-LF-Cable, Ribbon-Motor-Cable and Gap-Sensor-Cable.

  • Page 65: Stepping Motor (Space)

    Oki Data CONFIDENTIAL 3.3.11 Stepping Motor (Space) Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) Remove the Cover-Motor. (See 3.3.10) Remove the Ribbon-Feed-Assy. (See 3.3.10) Push the mini pitch belt in the direction of the arrow and remove the mini pitch belt 1 from the space motor pulley.

  • Page 66: Lf Motor

    Oki Data CONFIDENTIAL 3.3.12 LF Motor Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) Remove the Cover-Motor. (See 3.3.10) Remove the LF Motor Assy 1. Remove the two screws 2 and remove the Motor-LF 3 from the Bracket-LF-Motor 4.

  • Page 67: Gap Sensor

    Oki Data CONFIDENTIAL 3.3.13 Gap sensor Remove the pull-up roller Assy.(See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) Remove the Cover-Motor. (See 3.3.10) Remove the LF motor. (See 3.3.11) Disconnect the two Gap-Sensor-Cables from the Gap Sensor 1.

  • Page 68: Slider Pice-Slider

    Oki Data CONFIDENTIAL 3.3.14 Slider Pice-Slider Remove the pull up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) Remove the Cover-Motor. (See 3.3.10) Pull the Lever-Adjust 1 out of the shaft 3.

  • Page 69: Sp Belt

    Oki Data CONFIDENTIAL 3.3.15 SP Belt Remove the printhead. (See 3.3.1) Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the idle pulley bracket. (See 3.3.9) Remove the one screws 1 and remove the belt clamp 2.

  • Page 70: Paper Pan Assy

    Oki Data CONFIDENTIAL 3.3.16 Paper Pan Assy Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) Remove the platen. (See 3.3.5) Remove the Cover Motor 1. Remove the change lever 2 and the Gear Change 3.
  • Page 71 Oki Data CONFIDENTIAL 71 / 44209901TH Rev.2...

  • Page 72: Bottom Sensor, Photo Interrupter Front Sensor

    Oki Data CONFIDENTIAL 3.3.17 Bottom sensor, photo interrupter front sensor Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) Remove the platen. (See 3.3.5) Remove the paper pan Assy. (See 3.3.16) Slide the Beam-Lower 1 in the direction of the arrow by pressing the tab to remove the Paper-Pan-Assy 2.

  • Page 73: Cover Open Sensor

    Oki Data CONFIDENTIAL 3.3.18 Cover Open sensor Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the Bracket-side-L-Assy 1 (one screw). Remove the Cover-Open-Sensor 2 from Bracket-side-L-Assy (one screw). Remove the printer unit. (See 3.3.6) Disconnect the connector of the Cover-Open-Sensor from the Control-Board-Assy.

  • Page 74: Operation Panel Board And Operation Panel Cord

    Oki Data CONFIDENTIAL 3.3.19 Operation Panel Board and Operation Panel cord Remove the access cover. (See 3.3.4) Pry the upper cover's latches open by using a flathead screwdriver from the back of the upper cover. Release the six claws of the operation panel frame 1, remove the board 2.

  • Page 75: Control Board, Acf Board, Motor Fan

    Oki Data CONFIDENTIAL 3.3.20 Control Board, ACF Board, Motor Fan Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the Plate-shield-upper (four screws) 1. Disconnect the Motor-SP-Cable, Head-cord, Operation-panel-cable, Motor-LF-cable, Rib- bon-Motor-cable, Gap-sensor-cable, top-line-detection-sensor-cable, Cover-open-sensor- cable and Power-supply-cable.
  • Page 76 Oki Data CONFIDENTIAL 76 / 44209901TH Rev.2...

  • Page 77: Power Supply Unit (Board)

    Oki Data CONFIDENTIAL 3.3.21 Power supply UNIT (BOARD) Risk of Electric Shock There is a risk of electric shock during replacement of the power supply. Use insulating gloves or avoid direct contact with any conducting part of the power supply, and caution should be exercised during replacement.

  • Page 78: Front-Roller-Feed

    Oki Data CONFIDENTIAL 3.3.22 Front-Roller-Feed Remove the pull-up roller Assy. (See 3.3.3) Remove the upper cover. (See 3.3.4) Remove the printer unit. (See 3.3.6) From the Cover-Motor, disconnect the Motor-SP-Cable, Head-cord, operation-panel-cable, Motor-LF-Cable, Ribbon-Motor-Cable and Gap-Sensor-cable. Remove the Cover Motor. (See 3.3.10) Remove the Sheet-Guide-Front 1.

  • Page 79: Adjustment

    Oki Data CONFIDENTIAL ADJUSTMENT Be sure to carry out this adjustment with the printer mechanism mounted on the lower cover. Be sure to carry out this adjustment operation on a level and highly rigid work table (flatness: less than 0.039 inch or 1 mm) so as to minimize adjustment error.
  • Page 80 Oki Data CONFIDENTIAL Item Specification Drawing Adjustment method 4.1-1 Gap between platen <<Checking>> and print head Check the platen in three places: right and left ends and center. <<Adjustment procedure>> Set the release lever in the Rear-Push (1) If the right and...
  • Page 81 2SW, push 3SW (cut-sheet) (3) Check to confirm that the top positioning distance is within the specified range. (4) If this lies outside ex) ML620 operation panel is shown. the specified range, correct as described below. 81 / 44209901TH Rev.2...
  • Page 82 Oki Data CONFIDENTIAL Item Specification Drawing Adjustment method Correcting the paper Preset (1) Turn on power ± 0.5 mm top positioning while holding distance down 1SW and Preset Correction 2SW. Move 20/144 inches (3.53 mm) down from the reference position.
  • Page 83 Oki Data CONFIDENTIAL Item Specification Drawing Adjustment method C ± 0.5 mm Correcting cut-sheet (1) Set cut-sheet 40-line feed height (manual feed) A4- 55 kg paper in the sheet guide. (2) While pushing 2SW and 3SW, push power on. While pushing 2SW, push 3SW.
  • Page 84 Oki Data CONFIDENTIAL Item Specification Drawing Adjustment method Within ± 0.1 Correcting both- (1) Set paper with 55 Forward direction print kg ream weight. registration (2) Turn on power Reverse while holding down 2SW and 3SW. ±0.1 (3) While pushing...
  • Page 85 Oki Data CONFIDENTIAL Item Specification Drawing Adjustment method Paper cut position 0~0.3 mm (1) Set a continuous- check form roll (1P-55 Continuous-form kg, 10 inches) on 0~0.3 the rear tractor or Front tractor. (2) Press Power SW. Pull-up cover (3) Press 3SW to feed paper into the printer.
  • Page 86 Oki Data CONFIDENTIAL Item Specification Drawing Adjustment method Correcting paper cut 0~0.3 mm (1) Turn on power position while holding Correction down 1SW and Move 20/144 inches (3.53 mm) down from the reference position. 2SW. Move 19/144 inches (3.35 mm) down from the reference position.
  • Page 87 Oki Data CONFIDENTIAL Item Specification Adjustment method Slice level check (1) Set the following states · Set the adjust lever to 1 range. · Set the release lever to the cut position. · Remove the paper. · Remove the ribbon cassette.

  • Page 88: Cleaning And Lubrication

    Oki Data CONFIDENTIAL CLEANING AND LUBRICATION Cleaning [Cautions] Be sure to turn OFF the AC POWER switch before cleaning. Remove the AC power cord from the printer. Avoid dust inside the printer mechanism when cleaning. If a lubricated part has been cleaned, be sure to apply lubricating oil to that portion after cleaning.

  • Page 89: Lubrication

    Oki Data CONFIDENTIAL Lubrication This printer is designed to be maintenance free and requires no lubrication during normal operation. However it is necessary to apply lubricant in case the printer is disassembled, reassembled, cleaned or parts have been changed. Cleaning time Remarks: 1) Turn off the power before cleaning.
  • Page 90 Oki Data CONFIDENTIAL Lubrication point Ribbon feed gear Assy Apply a medium amount of GEP to the gear tooth surface Apply a medium amount of GEP to the contact portion of shaft and gear Apply a medium amount of GEP to the...
  • Page 91 Oki Data CONFIDENTIAL LF drive system and Gear Platen Apply a medium amount of GEP to the gear tooth surface Apply a medium amount of GEP to outsert and gear feed sliding surface Apply a medium amount of GEP to the shaft sliding surface...
  • Page 92 Oki Data CONFIDENTIAL Mode change Assy and Gear Platen Apply a medium amount of GEP to the gear tooth Apply a medium amount of GEP to the shaft sliding surface Apply a medium amount of GEP to the outsert and release lever...
  • Page 93 Oki Data CONFIDENTIAL Detail B Apply a medium amount of GEP to the release shaft and outsert sliding surface Detail A Apply a medium amount of GEP to the change plate gear and Change plate outsert sliding surface Release shaft...
  • Page 94 Oki Data CONFIDENTIAL Apply a medium amount of GEP of release lever sliding surface Adjustment lever Adjustment lever Apply a moderate amount of GEP to the sliding surface of detent 94 / 44209901TH Rev.2...
  • Page 95 Oki Data CONFIDENTIAL Pull-up-Roller-Assy Pull-up roller frame Pull-up roller shaft Apply a medium amount of GEP to the sliding surface of the pull-up roller frame and the pull-up roller shaft Detail A Apply a medium amount of GEP to the gear tooth serface...
  • Page 96 Oki Data CONFIDENTIAL Paper-Pan-Assy TOP VIEW (without roller frame, pressure TOP VIEW roller rear and release shaft) (with roller frame, pressure roller rear and release shaft) Rear pressure roller Apply a medium amount of GEP to the Apply a medium...
  • Page 97 Oki Data CONFIDENTIAL FRONT VIEW Front roller Front push holder Release shaft Apply a medium amount of GEP to the sliding surfaces of the Front push holder and Front roller Release shaft this area this area this area Apply a medium amount of GEP to the...
  • Page 98 Oki Data CONFIDENTIAL Paper-pan lower Apply a medium amount of GEP to the sliding surfaces of the paper-pan lower and roller frame both sides Paper-pan lower Apply a medium amount of GEP to Paper-pan lower the sliding surfaces of paper-pan...
  • Page 99 Oki Data CONFIDENTIAL Idle pulley bracket Apply a medium amount of GEP to the spring and Idle pully bracket Idle pulley bracket Idle pulley bracket Spring 99 / 44209901TH Rev.2...

  • Page 100: Troubleshooting And Repair

    Oki Data CONFIDENTIAL TROUBLESHOOTING AND REPAIR Items to Check Before Repair Check the inspection items specified in the instruction manual. Find out as many details of the trouble as possible from the customer. Inspect in the conditions as close as possible to those at the time the trouble occurred.

  • Page 101: Lamp Display

    Oki Data CONFIDENTIAL Lamp Display Printer mode display Table 6.2 LED CONDITION ALARM ALARM PRINT QUALITY TEAR CONTENTS TROUBLE SHOOTING CATEGORY ALARM Continuous paper or cut Paper end alarm Set new paper. sheet paper end. Change lever is set to TOP Set the lever to •...
  • Page 102 Oki Data CONFIDENTIAL 102 / 44209901TH Rev.2...
  • Page 103 Oki Data CONFIDENTIAL Motor Fan Print Head AC connector Ribbon Motor Switch ACF Board Power Supply UNIT (BOARD) Photo Interrupter Sensor Home Bottom Sensor Sensor Front Sensor SP Motor Operation Panel Board Cover Open Sensor LF Motor 103 / 44209901TH Rev.2...

  • Page 104: Connection Circuit Check For Printhead And Sp/Lf/Rbn Motor

    Oki Data CONFIDENTIAL Connection Circuit Check for Printhead and SP/LF/RBN Motor Printhead Control board side Flexible flat cable Print head board side Signal connector Connector name and pin name and a pin number number D2-10 CN2-14 EAD1 CN2-22 D2-2 EAD2...
  • Page 105 Oki Data CONFIDENTIAL Line Feed Motor Resistance of each coil should be about 5.8Ω. LFMOT LFOUT1A LFOUT1B LFOUT2A LFOUT2B LF Motor SP Motor Resistance of each coil should be about 4Ω. SPMOT FUSE +40V SPOUTA SPOUTA- SPOUTB SPOUTB- SP Motor 105 / 44209901TH Rev.2...
  • Page 106 Oki Data CONFIDENTIAL Ribbon Motor Resistance of each coil should be about 7.6Ω. RBMOT RBOUT1A RBOUT1B RBOUT2A RBOUT2B RIBBON Motor 106 / 44209901TH Rev.2...

  • Page 107: Troubleshooting Flow Chart

    Oki Data CONFIDENTIAL Troubleshooting flow chart Power is not supplied. Is the AC cable connected correctly? Connect the AC cable correctly. Are the voltage setting pins on the power supply unit configured correctly? 1 to next step Does the device operate when restoring power supply after turning the power switch off and changing the settings to ones suited to the AC voltage used? 1 Remove CN101 on power supply unit.
  • Page 108 Oki Data CONFIDENTIAL No spacing operation (The alarm LED Blinks) Is carriage assembly binding or jammed? Check around space motor to repair the mechanism of space belt, idle pulley, ribbon feed mechanism, and carriage frame etc. Replace Space motor assy.
  • Page 109 Oki Data CONFIDENTIAL Homing does not end normally Check around space motor to repair the mechanism. (Space belt, idle pulley, ribbon feed mechanism, carriage frame and ribbon protector.) Remedied? Replace Space motor assy. Replace Space motor assy. Remedied? Replace Control Board.
  • Page 110 Oki Data CONFIDENTIAL Paper jam while paper insertion Jam 1 Check the ribbon protector. Check the pull up roller cover is closed properly. Pull up roller cover Platen Ribon Protector Paper Jam 2 (wrinkled paper) Check around pressure roller mechanism.
  • Page 111 Oki Data CONFIDENTIAL Smearing/missing dots Does ALARM LED blink and display alarm? See Tables 6.2 and 6.3 for troubleshooting information. Replace Printhead. Remedied? Replace Control Board. Remedied? Replace Carriage cable or Space motor assy. 111 / 44209901TH Rev.2...
  • Page 112 Oki Data CONFIDENTIAL Faint or dark print Is the print head gap set properly? Adjust the printhead gap (see section 4). Remedied? Replace Printhead. Remedied? Replace Control Board. Remedied? Replace Ribbon feed mechanism. 112 / 44209901TH Rev.2...
  • Page 113 Oki Data CONFIDENTIAL Ribbon feed trouble Remove the ribbon cartridge. Does the ribbon drive shaft rotate? Change Ribbon cartridge. Remove Ribbon feed mechanism. Does the ribbon drive shaft rotate? Replace Ribbon feed mechanism. Replace Ribbon motor assy. 113 / 44209901TH Rev.2...
  • Page 114 Oki Data CONFIDENTIAL Line feed trouble Turn the power off, and rotate the platen manually. Does the platen rotate smoothly? Is the Gear Platen (L) broken? Replace Platen assembly. Is the gear line on the left side broken? Replace the LF motor assembly or gear on the frame side.
  • Page 115 Oki Data CONFIDENTIAL Malfunction of switch on operation panel Is the CN1 of Operation panel connected to the OP on the Control Board? Connect the cable properly. Replace Operation panel board. Remedied? Replace Control Board. 115 / 44209901TH Rev.2...
  • Page 116 Oki Data CONFIDENTIAL Data receiving failure Is the SEL LED blinking? Printer went into the print suppress mode. Wait until printer to receives DC1 code, or change the menu item “Print sup- press-Ineffective” when the function is not required. Is the I/F RS232C?
  • Page 117 Oki Data CONFIDENTIAL 10-2 (RS232C I/F) Printer I/F pin assignment. Is the correct cable used? 2 pin, 3 pin, 11 pin, 20 pin, Change I/F cable. 6 pin. Is ALARM LED blinking? See tables 6.2 and 6.3 for the troubleshooting.

  • Page 118: Appendix A Pcb Layout

    Oki Data CONFIDENTIAL Appendix A PCB LAYOUT Power Supply Board Control Board CENT SPMOT SNS3 SPDV EXIF SNS2 SNS1 MDSN2 MDSN1 118 / 44209901TH Rev.2...
  • Page 119 Oki Data CONFIDENTIAL Operation Panel Board LED3 LED2 LED1 LED9 LED10 LED7 LED6 LED5 LED4 LED8 LED11 CSF Connector Board 119 / 44209901TH Rev.2...

  • Page 120: Appendix B Rs-232C Serial Interface Board (Option)

    Oki Data CONFIDENTIAL Appendix B RS-232C SERIAL INTERFACE BOARD (OPTION) GENERAL This section describes the operation of the RS-232C Serial Interface board installed in the Printer as an option using a start-stop synchronization and serial communications circuit. This serial interface board is capable of transmitting and receiving simultaneously at speeds up to 19,200 bits per second.

  • Page 121: Circuit Description

    Oki Data CONFIDENTIAL Circuit Description A block diagram is shown in Figure B-1. SDV1 (HIN202E) SDV2 (HIN202E) SCONECT-N Control board and connection terminal Figure B-1 Block Diagram 2.2.1 Operation at power on It becomes possible to use the RS232C board because SOC of the control board recognizes that the RSCONECT-N signal is connected with OV when the power supply is turned on.

  • Page 122: Communication Procedure Flowchart

    Oki Data CONFIDENTIAL Communication Procedure Flowchart 2.3.1 Mode a Ready/Busy Received one character ? is DSR signal valid ? DSR signal is High ? Parity Error ? Store 0x40("@") in buffer. Framing Error ? Store 0x3f("?") in buffer. Overrun Error ? Store 0x21("!")

  • Page 123: Mode B

    Oki Data CONFIDENTIAL 2.3.2 Mode b X-ON/X-OFF Received one character ? is DSR signal valid ? DSR signal is High ? Parity Error ? Store 0x40("@") in buffer. Framing Error ? Store 0x3f("?") in buffer. Overrun Error ? Store 0x21("!") in buffer.

  • Page 124: Troubleshooting Flowchart

    Oki Data CONFIDENTIAL TROUBLESHOOTING FLOWCHART Before Repairing a Fault Before servicing the printer, ask the customer in what situation the trouble occurred and record the response. Before starting troubleshooting, operate the printer in the same situation as that at the time of trouble occurrence to see if the same trouble occurs again.

  • Page 125: Local Test

    Oki Data CONFIDENTIAL Local Test 3.3.1 Circuit test mode 3.3.1.1 Setting Diagnostic test (set by menu) Test connector Connect the test connector shown in Figure B-9 to the interface connector Equivalent to Cannon DB-25P Figure B-9 Test Connector Connection Diagram 3.3.1.2 Function...

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