Oki ML420 Maintenance Manual

Disclaimer Every effort has been made to ensure that the information in this document is complete, accurate, and up-to-date. The manufacturer assumes no responsibility for the results of errors beyond its control. The manufacturer also cannot guarantee that changes in software and equipment made by other manufacturers and referred to in this guide will not affect the applicability of the information in it. Mention of software products manufactured by other companies does not necessarily constitute endorsement by the manufacturer. While all reasonable efforts have been made to make this document as accurate and helpful as possible, we make no warranty of any kind, expressed or implied, as to the accuracy or completeness of the information contained herein. The most up-to-date drivers and manuals are available from the web site: http://www.okiprintingsolutions.com Oki Data CONFIDENTIAL

PREFACE This maintenance manual describes how to maintain the printer in the field. This manual is for customer engineers. For further information, refer to the Users Manual for handling or operating the equipment. The relation between the destination point and the model name of this printer is as follows. For ODA ML420 ML421

Contents 1. CONFIGURATION ...............................................................................................6 1.1 Standard Printer Configuration ............................................................................................ 6 1.2 Options................................................................................................................................. 7 2. THEORY OF OPERATION ..................................................................................9 2.1 Electrical Operation.............................................................................................................. 9 2.1.1 Summary................................................................................................................. 9 2.1.2 Microprocessor and the Peripheral Circuit .............................................................. 9 2.1.3 Initialization ........................................................................................................... 16 2.1.4 Interface Control ................................................................................................... 17 2.1.5 Print Control .......................................................................................................... 20 2.1.6 SP/LF Motor Control ............................................................................................. 22 2.1.7 Operation Panel .................................................................................................... 25 2.1.8 Alarm Circuit ......................................................................................................... 27 2.1.9 Power Supply Circuit............................................................................................. 30 2.2 Mechanical Operation ........................................................................................................ 31 2.2.1 Printhead Mechanism and Operation ................................................................... 31 2.2.2 Spacing Operation ................................................................................................ 34 2.2.3 Head Gap Adjusting .............................................................................................. 35 2.2.4 Ribbon Drive ......................................................................................................... 37 2.2.5 Paper Feed Operation .......................................................................................... 38 2.2.6 Paper Detection Mechanism ................................................................................. 48 2.2.7 Automatic Sheet Feed .......................................................................................... 50 2.2.8 Paper Park Function ............................................................................................. 52 3. ASSEMBLY/DISASSEMBLY ..............................................................................53 3.1 Precaution for Parts Replacement ..................................................................................... 53 3.2 Service Tools ..................................................................................................................... 54 3.3 Disassembly/Reassembly Procedure ................................................................................ 55 3.3.1 Printhead............................................................................................................... 57 3.3.2 Ribbon Protector ................................................................................................... 58 3.3.3 Pull-up Roller Assy................................................................................................ 59 3.3.4 Upper Cover Assy, Access Cover Assy and Sheet Guide Assy ........................... 60 3.3.5 Gear Case Assy .................................................................................................... 61 3.3.6 PC Connector ....................................................................................................... 62 3.3.7 Space Motor, Guide Roller Assy ........................................................................... 63 3.3.8 Space Rack........................................................................................................... 64 3.3.9 Carriage Cable ...................................................................................................... 65 3.3.10 Backup Roller Holder Assy ................................................................................... 66 3.3.11 Platen Assy ........................................................................................................... 67 3.3.12 Control Board (NNS) ............................................................................................. 68 3.3.13 LF Motor................................................................................................................ 69 3.3.14 Operation Panel Board (LEOP) ............................................................................ 70 3.3.15 Power Supply Board (TPW) .................................................................................. 71 3.3.16 Transformer Assy.................................................................................................. 72 3.3.17 Change Lever and Gears...................................................................................... 73 3.3.18 Carriage Shaft ....................................................................................................... 74 3.3.19 Paper Pan ............................................................................................................. 75

3.3.20 Rear Tractor Assy ................................................................................................. 76 3.3.21 Rear Pressure Assy .............................................................................................. 77 3.3.22 Switch Lever ......................................................................................................... 78 4. ADJUSTMENT ...................................................................................................79 5. CLEANING AND LUBRICATION .......................................................................87 5.1 Cleaning ............................................................................................................................. 87 5.2 Lubrication ......................................................................................................................... 88 6. TROUBLESHOOTING AND REPAIR ................................................................95 6.1 Items to Check Before Repair ............................................................................................ 95 6.2 Troubleshooting Table ....................................................................................................... 95 6.3 Lamp Display ..................................................................................................................... 96 6.4 Connection Circuit Check for Printhead and SP/LF Motor............................................... 100 6.5 Troubleshooting flow chart ............................................................................................... 102 APPENDIX A PCB LAYOUT ...............................................................................114 APPENDIX B SPARE PARTS LIST ....................................................................115 APPENDIX C RS-232C SERIAL INTERFACE BOARD (OPTION)....................126 1. GENERAL ............................................................................................................................ 126 2. OPERATION DESCRIPTION .............................................................................................. 126 2.1 Element Description .................................................................................................. 126 2.2 Circuit Description ..................................................................................................... 127 2.2.1 Operation at power on .................................................................................... 127 2.2.2. RS-232C interface .......................................................................................... 127 2.3 Communication Procedure Flowchart ....................................................................... 128 2.3.1 Mode a .......................................................................................................... 128 2.3.2 Mode b .......................................................................................................... 129 3. TROUBLESHOOTING FLOWCHART ................................................................................. 130 3.1 Before Repairing a Fault............................................................................................ 130 3.2 Troubleshooting ......................................................................................................... 130 3.3 Local Test .................................................................................................................. 133 3.3.1 Circuit test mode ............................................................................................ 133

1. CONFIGURATION 1.1 Standard Printer Configuration This printer consists of the following assemblies: Figure 1-1 Configuration Upper cover Access cover assy Platen knob Sheet guide assy Control board Power supply board Transformer assy Pull-up roller assy Main chassis assy Operation panel assy

1.2 Options (1) Cut sheet feeder unit (CSF) (Narrow and wide versions available) Dual-bin CSF Single-bin CSF (2) Pull-tractor assy Attachment assy Attachment assy

(3) Bottom push tractor unit (4) Roll paper stand (Narrow only) (5) RS232C Serial interface board

2. THEORY OF OPERATION 2.1 Electrical Operation The electrical operation of the printer circuit is described in this section. 2.1.1 Summary Figure 2-1 shows the block diagram of the printer. The control board is made up of the microprocessors, peripheral circuits, drive circuits, sensors and interface connectors. The power to the control board is supplied by the power board through the connector cord. The power to other electrical parts is also distributed through the connectors within the control board. 2.1.2 Microprocessor and the Peripheral Circuit (1) Microprocessor This processor is a CMOS single-chip computer with integrated peripheral device functions and a 16 bit MPU core, all OKI original architecture. The processor has a 20 bit address bus and a 16 bit data bus. It is capable of accessing up to 1M word program memory and 1M bytes of data memory. The following characteristics are also provided: • Built-in type data memory of 512 bytes • 8-bit 4-channel A/D converter × 1 • 16-bit automatic reload timer × 2 • 8-bit serial port × 2 • 8-bit parallel port × 3 (bitwise I/O specification available) And others. The function of this microprocessor is to provide a central mechanism for the entire printer by executing the control program through the LSI and driver circuits.

Figure 2-1 HTEMP 14.456 MHz 4 POWLEV HTEMP HEADGAP SPTEMP A/D PE-SENSOR OPERATION PANEL Serial Alarm -circuit HD alarm Over-V alarm Over-V alarm FAN alarm Power-off Transformer Rectifier circuit 50 volt 12 volt 5 volt 42V -8V 3.3V 5VS Reset circuit I/F-IPT Print-IPT EEPROM 1Kbits Microproce- ssor ADDRESS Serial Serial ROM 4Mbit AD-BUS DRAM 4Mbit LSI RESET 5VD POWLEV Fuse 42 V SP/LF driver HD alarm SPTEMP Head driver Photo sensor HEAD M M SP Thermister LF FAN HTEMP (opt.) Serial- I/F (opt.) Roll paper stand (opt.) CSF AC-input SW AC Fuse Divider Converter Release-SW Bottom-SW HEADGAP-SW HEADGAP Para- I/F USB I/F M USB Controller

MPU CLOCK A0~A17 PG-N PSEN-N D0~D15 CSO PSEN CE OE PG-N PSEN-N D0~D15 A0~A17 MPU ROM (2) Program ROM This is a 256 × 16 bits (4M bit) EPROM or MASK ROMwith the control program for the printer stored. The MPU executes instructions under this program. The program ROM is assigned to the program memory area of the MPU and is fetched by the PSEN-N signal of the MPU. The following shows the operation of the memory access.

A0~A8 CAS-N RAS-N UCAS-N LCAS-N WR-N RD-N WRH-N WRL-N RAM MPU P03 CS1 WRL P11 RD OE D0~D15 RAS UCAS LCAS WE T1 T2 T3 Clockout* A0~A8 RAS-N VCAS-N LCAS-N RD-N D0~D15 (Read) WR-N D0~D7 (Write) 16-bit bus, Word instruction ALS139 ALS11 T4 * Clockout is provided when the original excitation is selected. (3) RAM The RAM is CMOS dynamic RAM with 256K × 16-bit (4Mbit), and used as buffers (such as receiving buffer, printing buffer, DLL buffer and working buffer). The following shows the examples of the memory access operation.

(4) USB Controller The USB Controller detects and controls the USB interfacee. The following shows the USB Controller access operation. D0~D7 P02 PSEN MPU USBCS-N RD-N WRL-N A0~A7 USB Controller Clockout * A0~A7 D0~D7 (Write) USBCS-N RD-N WRL-N D0~D7 (Read) CE WR PO2 WRL RD RD * Clockout is provided when the original excitation is selected.

MPU EEPROM EEDIN-P EECS-P EEDOUT-P EECLK-P P24 P27 P25 P26 D1 CS DO SK Ready Bus twp D0 D15 A0 A5 1 1 0 Start code Operation code Address Data tCS PRE = O PE EECS-P EECLK-P EEDIN-P EEDOUT-P Address Start code Operation code EEDOUT-P EEDIN-P EECLK-P EECS-P D15 D0 D15 D0 D15 0 A0 A5 0 1 1 t CS PRE = O PE = X (5) EEPROM The EEPROM is a CMOS serial I/O type memory which is capable of electrically erasing and writing 1,024 bits. The EEPROM contains menu data. The following shows the memory access operation. Read cycle timing (READ) Write cycle timing (WRITE)

MPU A/D bus LSI RD WRL P01 ALE ALE RD-N WRL-N LSICS-N ALE-P RDN WRL LSIC RAS 1 P07 RAS 0 RAS-N Clockout* A0~A19 LSICS-N ALE D0~D7 (Read) RD-N D0~D7 (Write) WRL-N Address Address Data Data * Clockout is provided when the original excitation is selected. (6) LSI This LSI detects and controls the SP motor speeds by monitoring the two phase sensor signals obtained from the DC motors and modifying the excitation phases as appropriate. This LSI is connected in multiplex to the MPU.

End I/F BUSY OFF Serial I/F I/F ACK Send Parallel I/F LF Motor Phase Initialization Carriage Homing RAM Clear LSI Initial Setting and I/F Busy ON External RAM CHECK LSI RESET ROM CHECK Internal RAM CHECK MPU Initial Setting MPU RESET Start 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 MPUs and LSIs. When resetting ends, the program starts and the LSIs are reset by MPU via LSIRST-N. Reset operation by I-PRIME starts program to initialize, but does not reset the MPU. The program here sets the mode of the LSI including the MPU, checks the memories (ROMs and RAMs), then carries out carriage homing, and determines the LF motor phase. Finally, the program establishes the interface signals (P-I/F: ACK-P signal sending, and S-I/F: BUSY-N signal off) and lights the SELECT lamp to inform the ready state for receiving to the host side and ends the initialize operation.

A/D bus MPU LSI NBSY ACK NSTB RXD-N P16 NRXD Receive Data CN1 BUSY ACK-N STROBE-N Receive Data 1 to 8 STROBE-N BUSY ACK-N RXD-N 2~8µs 500ns max. 2.1.4 Interface Control (1) 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. The data is read upon receiving the RD-N signal from the MPU. When the data processing ends, the BUSY signal is set to off and the ACK-N signal in sent to request the next data. When reception is impossible because the buffer is full, the BUSY signal is sent to request stopping of data transmission. * The STROBE-based timing for the BUSY signal is adjustable from the Maintenance menu. ACK signal timing and BUSY signal timing can be adjusted from the Maintenance menu.

(2) Universal Serial Bus (USB) Universal Serial Bus Specification Revision 1.0 compliance. 1) Connector • Printer Side : “B” Receptacle (Upstream Input to the USB Device) • Cable Side : Series “B” Plug 2) Cable • Cable Length : Approx 1.8m (A cable must be met USB Spec Rev 1.1 for normal operation) Note: Cable is not supplied. 3) Table of USB I / F signals Contact Signal Name Typical Wiring Number Assignment 1 Vbus Red 2 D - White 3 D + Green 4 GND Black Shell Shield Drain Wire 4) Connector pin arrangement 2 3 4 1 5) Mode & Class of Device • Full - speed Driver • Self - powered Device 6) Data Signaling Rate • Full - speed function - 12Mb/s ± 0.25%(2500ppm) 7) Receive Buffer • 2044K Bytes 8) Interface circuit 3.3 V 1.5 kΩ Rs = 22 Ω TxD+ Rs Full-speed Buffer Rs TxD-

9) Signal Level • Input / Output Level Parameter Input Levels : High (driven) High (floating) Low Output Levels : Low High (driven) Output Signal Crossover Voltage Symbol VIH VIHZ VIL OL OH VCRS Min. 2.0 2.7 0.0 2.8 1.3 Max. 3.6 0.8 0.3 3.6 2.0 Units V V V V V V

HEAD DRIVE TIMING CHART DT1 DT2 HEAD DRIVE CURRENT Print Data MPU LSI DRIVER HEAD1-N~ HEAD9-N Print Head A/D bus HEAD1~ HEAD9 Control Board Print Data 2.1.5 Print Control Print data is transmitted as parallel data (HEAD1~HEAD9) from LSI to print head. LSI generates print timing and drive time.

As shown in the drawing left, the stroke length up to the platen is different for each pin. Number of impact pins Few Many Drive time Short Long Print Head Time Pin 3~6 Pin 1, 2, 8, 9 Pin coil current Pin 1,2 3~6 8,9 Platen Print Compensation Control The print compensation can be made as shown below: (a) Voltage compensation (See 2.1.8 “Alarm Circuit.”) (b) Temperature compensation (See 2.1.8 “Alarm Circuit.”) (c) Pin stroke compensation Head Gap Range 1 2 3 4 5 Print speed 100% 90% 85% 85% 80% Drive time Short Long (Drive time lengthens at each step.) (d) Simultaneous Compensation of the number of impact pins The MPU is provided with the compensation table for each pin to make necessary compensation. (e) Print mode compensation According to the thickness of the printing medium, the print mode is compensated as shown in the table below:

2.1.6 SP/LF Motor Control The MPU transmits serially the SP motor data and the LF motor control data too the SP/LF motor driver, according to the commands sent from the MPU. Transmission of SP/LF Motor Control Data MPU φA/φB φA/φB φB φA LF A1 A2 B1 B2 M SLATCH-N SDATA-N SCLK-N LSI MHM2025 SPU SPV SPW SPU Distri- butor Driver SPV SPW Decoder Space speed register LF phase register LF Overdrive register D/A D/A Driver Shift register SP LF1 LF2 SPM U SP Motor SPM V SPM W U V W P23 P20 P22 SDATA-N SCLK-N SLATCH-N D7 D6 D5 D4 D3 D2 D1 D0

SP truth table HALL AMP INPUT OUTPUT SPU SPV SPW U V W H H L OPEN L H H L L L OPEN H H L H L H OPEN L L H OPEN H L L H H H OPEN L L H L H L OPEN SPU SPV SPW (1) Space motor control The SP motor driver (MHM2025) drives the three-phase brushless motor based on the phase signal (SPU, SPV and SPW) from the LSI and the speed instruction data from the MPU. The MPU can identify the current speed of the space motor by measuring through the LSI the pulse length of the output (øA, øB) of the slit encoder included in the space motor. By comparing the target speed for each print mode with the actual current speed to change the speed instruction data, the motor speed is accelerated or decelerated to maintain the specified speed for each print mode.

1/720" 1/120" SPU SPV SPW PHASE-A PHASE-B 1/144" IPT 10 CPI IPT 12 CPI IPT 15 CPI IPT 17 CPI IPT 20 CPI 1/180" 1/206" 1/240" (2) Encoder disk In the operation of the spacing motor, the PHASE-A and PHASE-B signals are generated when the encoder disk interrupts the photo sensor. The LSI divides these edge pulse signals in accordance with the print pitch, and sends the IPT signal to provide dot-on timing and carriage position detection timing. • UTILITY MODE [FORWARD] PHASE-B [REVERSE] PHASE-A (3) LF motor control The LF motor driver (MHM2025) drives the LF motor in two-phase or 1-2 phase bipolar, based on the phase changeover data and the output current data from the MPU. The data from the MPU is processed by a specific register contained in the LF motor driver to measure the overdrive time and to change the phase.

LSI Operation panel control IC OPTXD OPCLK OPCLR-N OPRXD 48 47 45 OPTD OPCK NPA2 OPRD Command and Data latch LED driver Switch controller +5V 46 2.1.7 Operation Panel The clock synchronization OPCLK of LSI is used to input the switch data and output the LED data through the operation panel control IC. A 2-byte (15 bits + 1 even parity bit) command (OPTXD) is transmitted to the Operation panel control IC in synchronization with the OPCLK signal. The Operation panel control IC decodes this command and when it is found to be legal, returns a 2-byte command response back to the LSI which includes data on Switch information, LED status, receive command ACK/NAK and 1 odd parity bit. Any transmission errors found cause the command to be reissued after the transmission of the OPCLR-N signal.

OPTXD OPCLK OPRXD OPCLR-N 1 2 3 2 3 1 6 7 5 or 8 bit0 bit7 Command (first) Command (second) Command response (first) Command response (second) Note bit0 bit7 Reset within IC Power ON Write instruction for IC reset IC write for LED data, etc. Read instruction for data read Response check for OK or NG Error notification Instruction for retransmission 1 2 3 4 7 8 5 6 NO YES Note: From the illustration above, you can see that the command and the command response are output at the same time. This is because the bit 0 to bit 3 of OPRXD are fixed so that the response can be returned before decoding the command.

50V R542 R541 POWLEV Voltage, 50V Pass number Print speed 38V or more 1 Pass 100% 25V to 37V 1 Pass 100~30% 25V or less 1 Pass 30% 2.1.8 Alarm Circuit (1) AC fuse open alarm (a) Head drive time alarm circuit This circuit monitors the drive time using the HDALM 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-N signal to turn on the Thyristor. This cause the secondary coil (50V) of the transformer to be short-circuited, causing an overcurrent to flow through the primary coil and making the AC fuse (transformer assy) open. (b) Overvoltage detection 50V, 12V and 5V voltages are monitored, at overvoltage alarm circuit turn-on, the ALM- N signal is transmitted to the thyristor, then the AC fuse (transformer assy) opens. (2) Alarm processing when DC power is low. 50V is converted into the POWLEV signal (0V to 5V) by R542 and R541 and input into the A/D port of the MPU to control the drive time and the print speed (pass number) of the head. (a) Head drive time The head drive time is lengthened to compensate for the amount of voltage drop by monitoring the POWLEV signal once every 500 µ sec. to control and maintain the impact necessary for each printing pin at the fixed value. (b) Print speed (3) FAN alarm The MPU detects 5V on the FANALM signal even through the fan is driven. 5V R512 FANALM-P

Stop Mode up Mode down Temp 125°C 118°C 116°C (4) Overheat alarm (a) Head overheat alarm The voltage of the output HTEMP signal of the thermistors, one of which is contained in the print head and the other in the SP/LF driver, is monitored by the A/D port of the MPU to control the voltage. Mode and print control Mode 1 2 3 4 5 6 7 PrintSpeed 100% 100% 100% 90% 80% 70% Stop DUTY 100% 87% 30% 13% 9% 5% 0% Pass 1 1 1 1 1 1 – • Characters less than 38ips Mode 1 2 3 4 5 6 7 PrintSpeed 100% 85% 70% 55% 40% 30% Stop DUTY 100% 87% 30% 13% 9% 5% 0% Pass 1 1 1 1 1 1 – • Characters more than 38ips Mode 1 2 3 4 5 6 7 PrintSpeed 100% 85% 70% 100% 80% 50% Stop DUTY 100% 87% 30% 13% 9% 5% 0% Pass 1 1 1 2 2 2 – • Only Image • When the temperature is between 118°C and 125°C, the mode switches sequentially to higher level. When the temperature falls below 116°C, the mode switches to lower level. • When the temperature exceeds 125°C, printing will stop. • When temperature gradient is steep, higher mode shall be specified directly.

Stop Temp 105°C 95°C (b) SP motor overheat alarm The voltage of the output SPTEMP signal of the thermistors, one of which is contained in the SP Motor, is monitored by the A/D port of the MPU to control the voltage. Mode and print control • When the temperature exceeds 105°C, printing will stop. Mode 1 2 3 PrintSpeed 100% 50% ~ 95% Stop Temp ~ 94°C 95°C ~ 104°C 105°C ~

SW AC Fuse Noise filter circuit Trans- former Power supply board Control board Rectifier Converter Rectifier Regulation Circuit +50V +12V +5V +5V -8V Converter +3.3V +50V Converter +42V The uses of output voltages and signals are described below. Voltage/signal Use +3.3V USB Controller drive +5V Logic IC / LED drive +12V Serial interface line, FAN motor drive +42V LF motor / SP motor drive +50V Printhead, Option CSF motor drive -8V Serial interface line 2.1.9 Power Supply Circuit This power supply circuit supplies the +3.3VDC, +5VDC, +12VDC, +42VDC, +50VDC, -8VDC.

2.2 Mechanical Operation 2.2.1 Printhead Mechanism and Operation (See Figure 2-2.) The printhead is a spring charged 9-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. Figure 2-2 Arrangement of the Head Pins View from the Tip of the Printhead (1) The printhead configuration: The printhead is composed of the following parts: (a) Wire guide (b) Spring assembly (Wire, Armature, Spring, Yoke, Spacer) (c) Magnet assembly (Magnet, core, coil, Yoke) (d) Printed circuit board (e) Fin

(2) Operation of printhead (See Figure 2-3.) (a) 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. (b) When a signal for a character to be printed is detected, a current flows through the coil. When the coil is activated, the magnetic flux (caused by the permanent magnet between the armature and the core) is canceled to eliminate the attraction force. The armature is driven in the direction of the platen by the force of the armature spring. The print wire fixed to the armature protrudes from the tip of the wire guide, strikes the paper through the ribbon and prints a dot on the paper. (c) After the character has been printed, the armature is magnetically attracted again and the print wires are again concealed under the wire guide. A thermistor in the printhead prevents burning caused by over-heating of the coil during extended continuous bi-directional printing. When the temperature of the coil exceeds a pre-determined limit (about 119°C) the control circuit detects a thermistor signal. Printing will then be intermittent or stop completely until the coil temperature falls below the limit value.

(2) When not printing (1) When printing Figure 2-3 Paper Print wire Printhead Platen Wire guide Paper Print wire Thermistor Magnet assembly Spacer Armature assembly Yoke Paper

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. It is driven by a DC motor mounted on the bottom of the carriage frame. Items included in the spacing mechanism are as follows: (a) DC motor with motor gear (b) Carriage frame (stationary yoke and motor driver board included) (c) Carriage shaft (d) Space rack (e) Sensor (f) Encoder disk (1) Spacing operation The carriage frame, on which the printhead and space motor are mounted, moves along the carriage shaft in parallel with the platen. When the spacing motor rotates counterclockwise, the driving force is transmitted to the motor gear. As the motor gear rotates, the carriage moves from left to right. Mechanically, it is designed in such a way that for every revolution of the DC motor, the carriage frame moves 0.8 inch (20.32 mm). At the same time the encoder disk rotates together with the motor and passes the sensor. The position of the carriage frame can be determined by counting the interrupts detected by the sensor. In the same way, the rotation of the space motor can be recognized and controlled by measuring the cycle of interrupts detected by the sensor. Figure 2-4 Slider Guide rail Printhead Carriage shaft Carriage frame Space rack Encoder disk Encoder sensor Motor gear

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. The adjusting screw, which is connected to the adjusting gear rotates when the adjusting lever is moved creating a fine gap adjustment. If the adjusting gear is pushed down, the adjusting screw can be turned with a screw driver to change the coarse gap adjustment. When the adjusting lever is set to range 2 ~ 5 the contact which is attached to the under side of the carriage cover will connect with the contact of the space motor PC board. The printer will reduce the printing speed automatically to ensure that adequate printing pressure is main- tained for multipart paper. And, the adjusting cam adjusts the headgap toward left and right side in accordance with the guide rail up and down as a position of the left end of it.

Figure 2-5 Range from 5 to 1 Range from 1 to 5 Platen Range Platen Narrows C.C.W. C.W. Carriage shaft Printhead Printhead Guide rail Adjusting screw Adjusting screw Adjusting gear Idler gear Adjusting lever 1 2 3 4 5 Adjusting cam Widens

2.2.4 Ribbon Drive (See Figure 2-6.) The ribbon driver mechanism moves the ribbon in synchronization with the space motor operation. The ribbon drive mechanism consist of the following items: (a) Ribbon drive gear assembly (b) Ribbon gear (space motor) (c) Ribbon cartridge (1) 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. (2) Ribbon feed operation When the space motor is activated, the ribbon gear rotates. The rotation is transmitted via the ribbon drive gear assembly to the drive gear in the ribbon cartridge, thus moving the ribbon. The feed direction of the ribbon is maintained by switching the rotational direction of the gears in the ribbon drive gear assembly. This ensures ribbon movement when bidirectional printing is used. Ink tank Drive gear Ribbon cartridge Figure 2-6

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: (a) Pulse motor with gears (b) Decelerating gear (c) Platen (d) Tractor feed unit (e) Pressure roller

(1) Cut sheet and continuous sheet switching mechanism (See Figure 2-7.) Three different paper paths can be selected and set by the change lever. (a) TOP (for cut sheet) When the cut sheet is used in the manual mode or fed by the CSF (option), set the change lever at the position marked TOP. [Operation] The driving force of the platen gear (R) is transmitted to the idle gear by setting the change lever to the TOP position. However, this causes the idle gear to be disen- gaged from the change gear, leaving it free. At this time, the pressure rollers (at the rear and the front) are pressed securely to the platen to feed the cut sheet. At the same time, the switch lever positions between the rear switch and bottom switch, to confirm to the control board that you are in the cut sheet mode. In the cut sheet mode, the control board automatically feeds the sheet up to the print start position after pausing for the wait time stored in the menu. (b) REAR (Continuous sheet from push tractor) When the change lever is set to REAR position, the change gear is engaged with the idle gear and the tractor gear to transmit the rotation of the platen to the push tractor shaft, and the continuous sheet is fed from the push tractor. At the same time, the switch lever turns on the rear switch, to confirm to the control board that you are in the continuous sheet mode. (c) BOTTOM (Continuous sheet from bottom feeder) (option) When the change lever is set in the BOTTOM position, the rotation of the platen is transmitted to the drive gear of the bottom tractor feed unit through the idle gear to feed the sheet which has been set in the bottom tractor feed. At the same time, the switch lever turns on the bottom switch, to confirm to the control board that you are in the continuous sheet mode. Correlation in Mechanism Mechanism Lever Position Rear Switch Bottom Switch Idle Gear Change Gear Tractor Gear Sheet Insertion Manual/ automatic CSF: Operation SW or instruction • • Operation SW or instruction • • Operation SW or instruction TOP REAR BOTTOM OFF ON OFF OFF OFF ON Rotate Rotate Rotate Stop Rotate Rotate Stop Rotate Stop

Change arm Change lever Change gear shaft Rear switch Bottom switch Switch lever Control Power supply Assy Release shaft Figure 2-7 TOP BOTTOM Change lever Tractor gear Change gear REAR Reset spring Platen gear (R) Platen Idle gear (Bottom tractor unit)

(2) 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 (LF idle gear, platen gear) to the platen. When using cut-sheet paper, the change lever must be in the TOP position to grab the paper, while disengaging the push tractor. When the change lever is set to the TOP position, the cut sheet is automatically fed in up to the print start position after pausing for the wait time stored in the menu. Figure 2-8 LF ldel gear Platen gear Platen Stepping motor (LF motor) Pressure roller

Figure 2-9 (3) Continuous paper feed operation (Rear) (See Figure 2-9.) The force transmitted to the platen, rotates the tractor gear through platen gear, the idler gear and the change gear. The rotation of the tractor gear makes the pin tractor belt rotate through a sheet feeder shaft, feeding the continuous paper. Paper Idle gear Platen gear Tractor gear Change gear

(4) Push and pull tractor mechanism (Option) (See Figure 2-10). This mechanism consist of an optional pull tractor and a standard push tractor mechanism. This mechanism can perform forward and reverse feed by setting continuous sheets to the push tractor and pull tractor. The rotation of the platen is transmitted to the push tractor and the pull tractor. Sheets are fed by these two tractors at the same time. To remove slack from the sheets, set the sheets according to the following procedure when using the push and pull tractors. 1 Set the change lever to the REAR position (setting the sheets to the push tractor to feed). 2 Set the paper, which is fed in front of the platen, to the pull tractor. 3 Set the change lever to the TOP position and feed paper using the platen knob. 4 If paper slack is removed, set the change lever to the REAR position. Figure 2-10 Idle gear Platen gear Drive gear Platen Pull tractor Pull tractor

Figure 2-11 Continuous sheet form Pull Tractor assembly Sheet feeder shaft Drive gear LF motor Idle gear LF Idle gear Platen gear Platen (5) Pull tractor mechanism (option) (See Figure 2-11.) Bottom feed of continuous sheets is possible only when an optional pull tractor unit is installed. The rotation of the platen is transmitted to the idle gear of the pull tractor unit through the platen gear at the left end of the platen. The rotation of the idle gear is transmitted to the drive gear, and continuous sheet forms are fed by the pull tractor being rotated through the sheet feeder shaft.

Figure 2-12 Idle gear Tractor change gear Tractor idle gear Tractor drive gear Platen gear Change gear Platen (6) Bottom push feed operation (Option) (See Figure 2-12.) The bottom push feed of the continuous sheet is possible only when the bottom tractor feed unit is installed. When the platen rotates, the rotational force of the platen is transmitted through the tractor idle gear and the tractor change gear to the tractor drive gear of the bottom push tractor, and the sheet of paper is fed in to the print start position.

(7) Paper clamp mechanism (See Figure 2-13.) When setting the change lever to the BOTTOM , TOP or REAR position, the operation of the front release gear arm changes according to the position of the release cam. And at the same time, the position of the cam installed to the front release gear shaft changes, and the open and close of the pressure roller. Position of change lever Open or close of front pressure roller Open or close of rear pressure roller BOTTOM OPEN OPEN TOP CLOSE CLOSE REAR OPEN OPEN

Figure 2-13 TOP BOTTOM REAR Change lever Front release gear arm Platen Release cam

Figure 2-14 Bottom paper end lever Paper end sensor Paper end lever Sensor lever Shaded portion B A 2.2.6 Paper Detection Mechanism (See Figure 2-14.) (1) Cut sheet detection When the cut sheet is inserted, the point A is pushed backward and the paper near end lever B rotates counter clockwise (CCW). At this time, the rear sensor lever rotates counterclockwise (CCW), the rear sensor lever and pulls out of the rear and top paper end sensor to detect that the sheet is provided. The procedure for the paper end is made in the reverse order, that is, its detection is performed when the paper end sensor is blocked. (2) Rear feed detection When the sheet is fed from the push tractor, the point B is pushed to the front side and the paper near end lever A rotates clockwise (CW). At this time, the rear sensor lever rotates counterclockwise (CCW), and pulls out of the rear and top paper end sensor to detect that the sheet is provided. The procedure for the paper end is made in the reverse order, that is, its detection is performed when the rear sensor lever intercepts the sensor. (3) Bottom feed detection When the sheet is fed from the bottom, the point C rotates clockwise (CW). When the bottom sensor lever rotates clockwise (CW), it pulls out of the bottom paper end sensor to detect that the sheet is provided. The procedure for the paper end is made in the reverse order, that is, its detection is performed when the bottom sensor lever intercepts the sensor.

Figure 2-15 Printhead Carriage frame assembly Platen Ribbon protector (4) Top line print mechanism (See Figure 2-15.) 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. The printing starts at the front end of the sheet, and continues uni-directionally until the front end of the sheet gets to the inside of the pull up roller cover. After that, that printing continues bi-directionally.

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] (1) When using the cut sheet 1) Set the change lever to the TOP position. (See Figure 2-16.) 2) Insert a sheet of paper between the platen and the paper shoot. 3) After the lapse of time selected by the “wait time” in the menu, the LF motor starts its operation to feed the sheet of paper up to the print position. 4) When the default is selected, the sheet of paper is feed in up to the position 0.85 inches (first dot position) from the upper end of the sheet. However, the 0 tear off mechanism allows the printing at the front end of the sheet by changing the TOF position. Figure 2-16 Time out Time selected on the menu Sheet setting PE Detection timer LF action TOP REAR BOTTOM SW2 SW1 TOP REAR BOTTOM

Detection of the sheet supplied PE LF action Line feed (about 3 inches) until the detection of the sheet supplied (2) When using the continouos paper 1) Set the change lever either to the rear side or the bottom side position. (See Figure 2-16.) 2) Set a sheet of paper either to the push tractor or the bottom tractor. 3) Press the “FF/LOAD” switch. 4) The LF motor starts its operation to feed the paper up to the print start position. 5) The paper is fed in up to the TOF position (Factory default: 0.85 inches from the top). Push down the “FF/LOAD” switch. When the “FF/LOAD” switch is pushed down, the LF motor feeds in the sheet about 3 inches. When the LF motor completes the operation and the sheet has not been fed in, the feeding operating operation becomes, ineffective, thus resulting in the feeding jam.

Paper end detection PE Reverse LF until paper end or 19 inches max. LF action PARK Reverse LF from P.E. Sensor to tractor feed assy. 2.2.8 Paper Park Function (Continuous paper) Continuous sheets which have been inserted can be reversed automatically by using the “PARK” button on the operation panel. 1) Press the “PARK” button on the operation panel. 2) Reverse LF is started and paper is fed in reverse until paper end occurs or 19 inches maximum have been fed. 3) The paper is fed in reverse, to leave the paper on the push-tractor or bottom-tractor. Alarm LED lights up when P.E. is not detected after 19 inches reverse feeding. Operator can press SEL key to turn off the ALARM LED then press PARK key to continue park function. This operation is required when the length of paper for parking is more than 19 inches.

3. 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. 3.1 Precaution for Parts Replacement (1) Remove the AC cable and the interface cable before disassembling or assembling. (a) Turn off the AC power switch. Remove the AC input plug of the AC cable from the receptacle. Remove the AC cable from the inlet on the printer. (b) To connect the AC cable again, connect it to the inlet on the printer first, then insert the AC input plug into a receptacle. Interface cable Inlet AC cable AC receptacle AC input plug (2) Do not disassemble the printer as long as it is operating normally. (3) Do not remove unnecessary parts, and limit the disassembly area as much as possible. (4) Use the designated service tools. (5) Carry out disassembly in the prescribed sequence; otherwise, damage to the parts may result. (6) It is advisable to temporarily install screws, snap rings and other small parts in their original positions to avoid losing them. (7) Whenever handling the microprocessors, ROM, RAM IC chips and boards, do not use gloves which may cause static electricity. (8) Do not place the printed circuit board directly on the equipment or on the floor. (9) If adjustment is specified in the middle of installation, follow the instructions.

3.2 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 1 No. 1-100 Phillips 1 Screws screwdriver 2.6 mm 2 No. 2-200 Phillips 1 Screws screwdriver 3-5 mm 3 No. 3-100 1 screwdriver 4 Spring hook 1 5 J-YX4025–83335-3 1 Head gap adjustment 6 Volt/ohmmeter 1 7 Feeler gauge 1 Head gap adjustment 8 Pliers 1 9 No. 5 nippers 1 10 5N (500g) (1.1 lbs) 1 bar pressure gauge No. Service Tool Q’ty Use Remarks

Figure 3-1 Printer unit 3.3 Disassembly/Reassembly Procedure This section explains the assembly replacement procedures according to the following disas- sembly system. [Parts Layout] Operation panel board Control board Power supply board Transformer assy Upper cover assy Printhead Printer unit

[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 and sheet guide 3.3.5 Gear case assy 3.3.6 PC connector 3.3.7 Space motor and guide roller assy 3.3.8 Space rack 3.3.9 Carriage cable 3.3.10 Back-up roller holder assy 3.3.11 Platen assy 3.3.19 Paper pan 3.3.12 Control Board (NNS) 3.3.13 LF motor 3.3.18 Carriage shaft 3.3.14 Operation panel Board (LEOP) 3.3.15 Power Supply Board (TPW) 3.3.16 Transformer assy 3.3.17 Change lever and gears 3.3.20 Rear tractor assy 3.3.21 Rear pressure assy 3.3.22 Switch lever

Figure 3.3.1 Figure 3.3.2 3.3.1 Printhead (1) Open the access over. (2) Pull up and rotate the head clamp 1 to unclamp the printhead 2 as shown fig. 3.3.1. (3) Disconnect the printhead 2 from PC connector 3. (4) To install, follow the removal steps in the reverse order. Notes on installation: (1) Insert the printhead 2 into the PC connector 3 while pushing it against the carriage frame 4. (2) The head clamp 1 must surely be sandwiched between printhead 2 and carriage frame 4 as shown Figure 3.3.2. (3) Be sure to check the gap between platen and printhead (see 4). (4) Be careful not to touch the print head while it is very hot. (5) Make sure that there is not any dust or oil on the connector contact section A. If it is found, wipe it off by alcohol. 1 2 4 1 2 2 3 4 1 A

3.3.2 Ribbon Protector (1) Remove the printhead (see 3.3.1). (2) Open the pull-up roller cover 1. (3) Raise and remove the ribbon protector 2. (4) To install, follow the removal steps in the reverse order. 2 1

3.3.3 Pull-up Roller Assy (1) Open the access cover 1. (2) Lift up the sheet guide Assy 4 to remove. (3) Tilting the pull-up roller Assy 2 toward the front, remove from the shaft of platen Assy 3. (4) To install, follow the removal steps in the reverse order. 4 3 2 1

3.3.4 Upper Cover Assy, Access Cover Assy and Sheet Guide Assy (1) Pull off the platen knob 1. (2) Turn the change lever 2 toward the bottom position. (3) Insert a flat-blade screwdriver into grooves (5 places) (4 places for narrow type) of frame and twist to disengage claws of upper cover 3. (4) Raise the front side of upper cover Assy 3 and shift toward the rear to disengage claws (6 places) (5 places for narrow type) of frame. (5) Raise the upper cover Assy 3 to remove. (6) Open the access cover Assy 4 toward the front to remove. (7) Lift up the sheet guide Assy 5 to remove. (8) To install, follow the removal steps in the reverse order. Remark on assembly: Match the posts A at the both sides of the Sheet Guide 5 with the arrow marks on the upper cover. Push the Guide into the Cover. 2 3 1 4 5 A

3.3.5 Gear Case Assy (1) Remove the printhead (see 3.31). (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Move the carriage Assy to right hand side, remove two screws 1, then the space motor 2. (4) Disconnect a carriage cable. (5) Disengage claws (4 places). Using a flat-blade screwdriver, push to widen the claw for easy disengagement. (6) Remove the gear case Assy 3 in upper direction and release the carriage cable from the cable clamp of the gear case Assy. (7) To install, follow the removal steps in the reverse order. Note on installation: (1) To assemble, align the direction of the SP motor axis 4 with the Gear Hole of the Gear Case assy. (2) Be sure to check, and adjust if necessary, the gap between platen and printhead (see 4-1). 2 4 3 1

3.3.6 PC Connector (1) Remove the printhead (see 3.3.1). (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Remove the gear case Assy (see 3.3.5). (4) Remove the PC connector 1 from the space motor Assy 2. (5) To install, follow the removal steps in the reverse order. Note on installation: (1) Do not touch the space motor 2 or terminals of PC connector 1. Also, take care to avoid dust or foreign matters. (2) After installation, check and adjust the gap between platen and printhead (see 4-1). (3) Make sure that there is not any dust or oil on the connector contact section A. If it is found, wipe it off by alcohol. 1 2 (rear side) A

3.3.7 Space Motor, Guide Roller Assy (1) Remove the printhead (see 3.3.1). (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Remove the gear case Assy (see 3.3.5). (4) Remove the PC connector (see 3.3.6). (5) Remove screw 2, then the guide roller Assy 3 from the space motor 1. (6) To install, follow the removal steps in the reverse order. Notes on installation: (1) Do not touch the terminals of space motor 1. Also, take care to avoid dust or foreign matters. (2) When installing the guide roller Assy 3, push portions A and B against the space motor 1. (3) When installing the space motor 1, align the face C with carriage frame 4 and push portion D against the frame. (4) After installation, check and adjust the gap between platen and printhead (see 4-1). 3 4 1 2 A B D C 3

3.3.8 Space Rack (1) Remove the printhead (see 3.3.1). (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Remove the gear case Assy (see 3.3.5). (4) Remove the space motor (see 3.3.7). (5) Remove the spring 1. (6) Disengage the claw on left side of space rack 2 from the frame, and remove the space rack 2 in upper direction. (7) To install, follow the removal steps in the reverse order. Note on installation: (1) After installation, check and adjust the gap between platen and printhead (see 4-1). 2 2 1 1 2

3.3.9 Carriage Cable (1) Remove the printhead (see 3.3.1). (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Remove the gear case Assy (see 3.3.5). (4) Remove the space motor (see 3.3.7). (5) Remove the space rack (3.3.8). (6) Remove two screws 1, release the Control Board 2 and PCB sheet 9 by lifting clamp 8, and disconnect cable from connector 3, 4, 5, 6. (7) Remove carriage cable 7 from fasteners on frame. (8) To install, follow the removal steps in the reverse order. Note on installation: (1) Take care not to fold the carriage cable 7 during installation. Curve slightly the carriage cable 7 when assembling into the fasteners. (2) Make sure that the paper end lever A will not contact the Paper end Sensor 0 when mounting the Control Board. (3) Make sure that there is not any dust or oil on the connector contact sections A to D. If it is found, wipe it off by alcohol. 7 0 A 7 2 Claw Claw A B C D 8 6 4 3 9 2 5 1

3.3.10 Backup Roller Holder Assy (1) Remove the printhead (see 3.3.1), (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Remove the gear case Assy (see 3.3.5). (4) Remove the space motor (see 3.3.7). (5) Remove the backup roller spring 2. Disengage claws (2 places) of roller holder from the carriage frame 1, and remove the backup roller holder assy 3. (6) To install, follow the removal steps in the reverse order. 2 3 Claw (2 places) Note: Small round hole with metal tip on back up roller holder assy 3 should be facing up when installing.

3.3.11 Platen Assy (1) Remove the printhead (see 3.3.1). (2) Remove the ribbon protector (see 3.3.2). (3) Remove the pull-up roller Assy (see 3.3.3). (4) Remove the upper cover (see 3.3.1 (1) – (5)). (5) Turn the change lever 1 to the bottom position. (6) Push in the lock levers 2 on both sides to unlock from the frame, then rotate them upward by 90°. (7) Remove the platen Assy 4 from base frame. (8) To install, follow the removal steps in the reverse order. 2 2 1 2 4 2

3.3.12 Control Board (NNS) (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Remove two screws 1, and release the Control Board 2 and PCB sheet 5 by lifting clamp 4. (3) Disconnect all cables from Control Board 2. (4) To install, follow the removal steps in the reverse order. Note on installation: (1) Insert one sensor lever 3 between sensor when installing the Control Board 2. (2) Make sure that there is not any dust or oil on the connector contact section A. If it is found, wipe it off by alcohol. 4 2 1 5 3 3 Sensor A 2 4

3.3.13 LF Motor (1) Remove the printhead (see 3.3.1). (2) Remove the ribbon protector (see 3.3.2). (3) Remove the pull-up roller Assy (see 3.3.3). (4) Remove the upper cover (see 3.3.4 (1) – (5)). (5) Remove the platen Assy (see 3.3.11). (6) Remove the driver board (see 3.3.12). (7) Remove the left FG plate 1. (8) Release the lock A to remove the LF motor 2. (9) To install, follow the removal steps in the reverse order. Remark on assembly: (1) Press the LF Motor Cable with a portion A of the Motor Plate. A 1 Lock A 2

3.3.14 Operation Panel Board (LEOP) (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Disconnect the cable 1 from connector 3 of Control Board 2. (3) Disengage claws on both sides from the frame, and remove the operation panel 4. (4) Open claws (4 places) and remove the operation panel Board 5 from the operation panel 4. (5) To install, follow the removal steps in the reverse order. Note on installation: (1) Make sure that there is not any dust or oil on the connector contact section A. If it is found, wipe it off by alcohol. 5 2 3 4 1 A

3.3.15 Power Supply Board (TPW) (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Disconnect two flexible cable 3 from the connector 2 the Power Supply Board 1. (3) Remove the cable 5 from the connector 4 on the Power Supply Board 1. (4) Remove two screws 6, and remove the Power Supply Board 1. (5) To install, follow the removal steps in the reverse order. Remark on assembly: (1) To mount the Power Supply Board, set the change lever to the top position so that the Switch Lever 7 will not hooked on the microswitches 8. 7 8 8 3 6 5 4 1 2 A Note on installation: (1) Make sure that there is not any dust or oil on the connector contact section A. If it is found, wipe it off by alcohol.

3.3.16 Transformer Assy (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Remove AC inlet 1 and AC switch 2 from the frame guide. (3) Disconnect the cable 3 from the connector 4 on the Power Supply Board 5. (4) Remove a screw 6 and disconnect ground cable 7. (5) Remove two screws 8 and shift the transformer Assy 9 to the left and remove it. 5 4 3 9 8 7 6 1 2

3.3.17 Change Lever and Gears (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Remove the reset spring 1, then remove the idle gear 2, the tractor gear 4 and the change gear 5. (3) Push back the protrusion of the Change Gear Shaft 6 with a flatblade screw driver to remove the change lever 3. (4) To perform mounting, follow the reverse procedure of removal. Remark on assembly: (1) To insert the change lever into the Change Gear Shaft 6, match the flat surface (D cut). 4 3 5 2 1 6 3 D cut

3.3.18 Carriage Shaft (1) Remove the printhead (see 3.3.1). (2) Remove the upper cover (see 3.3.4 (1) – (5)). (3) Remove the driver board (see 3.3.12). Remove the FG plate (L) 2. (4) Slide the carriage shaft 1 to the left side (in the direction of the arrow) to remove. (5) To perform mounting, follow the reverse procedure of removal. Note on installation: (1) After installation, check and adjust the gap between platen and printhead (see 4-1). 2 1 1

3.3.19 Paper Pan (1) Remove the printhead (see 3.3.1). (2) Remove the ribbon protector (see 3.3.2). (3) Remove the pull-up roller assy (see 3.3.2). (4) Remove the upper cover assy (see 3.3.4 (1) – (5)). (5) Remove the platen assy (see 3.3.11). (6) Release claws A . (7) Lift up the paper chute assy 1 and remove. (8) To perform mounting, follow the reverse procedure of removal. 1 A

3.3.20 Rear Tractor Assy (1) Remove the printhead (see 3.3.1). (2) Remove the ribbon protector (see 3.3.2). (3) Remove the pull-up roller assy (see 3.3.3) (4) Remove the upper cover (see 3.3.4 (1) – (5)). (5) Remove the reset spring (see 3.3.17 (3)) (6) Remove the tractor gear 1. (7) Shift the drive shaft 2 to the right side to remove (in the direction of the arrow). (8) To perform mounting, follow the reverse procedure of removal. Remark on assembly: (1) When the Tractor Assy (L) 3 (R) 4 have been detached from the Drive Shaft, align the protrusions 5 of the Pin Tractor Wheels to the same direction before assembly. 3 4 2 1 5

3.3.21 Rear Pressure Assy (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Remove the change lever and gears (see 3.3.17). (3) Remove the paper pan (see 3.3.19). (4) Remove the rear pressure roller 1. (5) Rotate the release shaft 2 and move it to the left to detach the release shaft 2. Match the Main Frame Rib A with the protrusion B of the Release Shaft. (6) Remove rear pressure SP assy 3. (7) To install, follow the removal step in the reverse order. Note: (1) At mounting release shaft 2, pay attention to the gear engagement of release shaft 2, change arm lever 6, change gear shaft 7. (2) There are 5 Rear pressure Spring Assemblies. Use two pieces which have larger spring diameter on the right side. Use three remaining pieces on the left side (for PD427). (3) Make sure that the Release Shaft 2 will be on top of the Support spring 4. (4) To assemble the Release Shaft 2, make sure that the protrusion of the switch lever 5 is in the U groove of the Release Shaft 2. 1 3 2 4 7 6 2 3 3 2 5 A B

Micro switch Switch lever Switch lever 3.3.22 Switch Lever (1) Remove the upper cover (see 3.3.4 (1) – (5)). (2) Remove the change lever and gears (see 3.3.17). (3) Remove the paper pan (see 3.3.19). (4) Remove the rear pressure assy (see 3.3.21). (5) Pull the Switch Lever toward you and remove it upward. (6) To install, follow the removal step in the reverse order. Remark on assembly: (1) At the time of the Switch Lever assembly, make sure that the Micro switch on the Power Supply Board works properly.

4. ADJUSTMENT (1) Be sure to carry out this adjustment with the printer mechanism mounted on the lower cover. (2) 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.

Item No. Specification Drawing Adjustment method Gap between the plat- en and the print head 1) Parallelism ad- justment 4–1–1 Variation of value at the left, the center and the right shall be less than 0.02 mm It shall be measured at 3 points: the left end, the center and the right end of the platen. Adjustment method (1) Gap between the platen and the print head at the left end and the right end shall be adjusted by rota- ting the adjust cam. (2) Set the adjust lever at the Range: 1. Press the adjust gear downward (in direction A) to push the adjust gear and the adjust gear out of mesh. (3) Adjust the gap by rotating the adjust screw in direction B or C while the adjust lever and the adjust gear are disengaged. (4) After adjustment, mark the adjust cam position with a red pen. 0.35±0.03 mm 2) Initial adjustment Left Right Adjust cam After adjust, mark the adjust composition with a red pen. Marking Platen Center Right Left Adjust lever Range : 1 Range : 5 Adjust screw Adjust gear Print head Adjust cam Carriage shaft

Item No. Specification Drawing Adjustment method Note 1) The head gap shall be measured with the change lever set to rear position. Note 2) The head gap shall be measured positioning the platen gear (R) craw on the top. Note 3) Move the adjust screw in clockwise direction (in direction B) to measure. Measure variation of gap when range is changed. 4–1–2 Gap=0.65±0.05 at the range 5. Adjust cam Platen Adjust gear Click of platen gear R Gap Adjust lever Print head Adjust screw Adjust spring Adjust gear Adjust lever A B C

Item No. Specification Drawing Adjustment method Gap between the con- tact and the monitor 0.3mm or more Confirm followings. Make sure that the gap between the con- tact and the motor PCB is 0.3 mm or more. At the time of printing test, make sure that the contact touches the motor PCB and it becomes reduced speed mode when the adjust lever is set to range 2 and 4. Touching Contact Motor PCB Adjust lever 0.3mm or more

Item No. Specification Drawing Adjustment method 4–2 1±0.5 Confirm followings. (1) When the change lever is set at Friction position, the gap between the platen and the paper pan at the rear side shall be 1±0.5mm. (2) When the change lever is set at Rear or Bottom position, the gap between the pla- ten and the paper pan at the front side shall be 1±0.5 mm. 4–3 Confirm followings. (1) When the change lever is set at Friction position, all the pressure rollers shall be pressed to the platen. (2) When the change lever is set at Rear or Bottom position, the gap between the pla- ten and the pres- sure roller at the rear side shall be 3mm. The front pressure rollers shall be pressed to the platen. Gap between the platen and the paper pan Platen Platen Rear Bottom Paper pan Paper pan Pressure roller Front pressure roller Friction position Rear, Bottom position 1±0.5 (At friction) 1±0.5 (Rear, Bottom position) Change lever Rear Bottom Change lever (Center friction) Gap between the platen and the pressure roller

Item No. Specification Drawing Adjustment method Rotation of the push tractor 4–4–1 To confirm: The tractor gear shall rotate smoothly when the change lever is set at Friction posi- tion. Backlash between gears 4–4–2 Approx. 0.05 to 0.11 mm To confirm: There shall be slight backlash between gears to allow smooth rotation of gears. (Backlash 0.05 to 0.11 mm) Change lever (Center friction) Push tractor Tractor gear Slight backlash

Item No. Specification Drawing Adjustment method Ribbon feed 4–5–1 To confirm: Ribbon shall be fed smoothly when the carriage is moved from side to side. Running load to spac- ing mechanism 4–5–2 To confirm: Make sure that the power is turned off at the time of measure- ment. 250g or less without a rib- bon cartridge Ribbon cartridge Ribbon feeding Ribbon Load measurement portion

Item No. Specification Drawing Adjustment method 4–6 To confirm: The idle gear of the LF motor and the platen gear (L) and the bias gear of the platen shall be in mesh in such way that the platen gear (L) and the bias gear rotate against each other to pinch the teeth of idle gear. The idle gear stays in mesh with the platen gear (L) and the bias gear and not locked. The bias gear and the platen gear shall be staggered by one teeth as shown in the drawing. Engagement of the double gear and the LF motor idle gear of the Platen Assy. Platen gear(L) LF Motor idle gear Bias gear Tension Good Not good (Locked)

5. CLEANING AND LUBRICATION 5.1 Cleaning [Cautions] 1. Be sure to turn OFF the AC POWER switch before cleaning. Remove the AC power cord from the printer. 2. Avoid dust inside the printer mechanism when cleaning. 3. If a lubricated part has been cleaned, be sure to apply lubricating oil to that portion after cleaning. (1) Cleaning time When the equipment operating time has reached six months or 300 hours, whichever comes first. (2) Cleaning tools Dry cloth (soft cloth such as gauze), vacuum cleaner (3) Places to be cleaned Table 5.1 lists the places to be cleaned: Table 5.1 Place to be cleaned Cleaning procedure Carriage shaft and the vicinity Remove paper waste and wipe off Paper travel surface stain, dust, ribbon waste. etc. Carriage shaft

5.2 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. (1) Cleaning time Remarks: 1) Turn off the power before cleaning. 2) Make sure that paper dust will not fall inside of the machine. • Cleaning period: 6 months of operation or 300 hours of operation, whichever the earlier. • Cleaning points: Carriage shaft and surroundings: Remove paper and ribbon dust. Paper path: Clean stains and dusts. Paper End Sensor Remove the dust on the Sensor. (2) Lubricant • Pan motor oil (or equivalent): PM • Molicort (or equivalent): EM-30L (3) Amount of lubricant • Medium amount A : Apply three to four drops of oil, or 0.008 inch (0.2 mm) thick grease. • Small amount B : Apply one drop of oil (0.006±0.002 g) (4) Areas to Avoid No. Do not lubricate Reason Remarks 1 Platen assembly To prevent stained paper (rubber face) and illegal paper feed. 2 Pressure roller (rubber To prevent stained paper Pay attention not to put face) the grease on the rubber face of the pressure roller. 3 Carriage shaft To stabilize carriage traveling load 4 Ink ribbon To prevent blurring of print image 5 Pin tractor To prevent stained paper 6 Flexible cable To prevent loose connection and crack 7 Motor PCB To prevent loose connection 8 Connector terminals To prevent loose connection

(5) Lubrication point 1. Ribbon feed gear Assy. 2. Space rack Drive gear shaft (upper and lower) PM-B (0.006–0.002g) Idle gear shaft (upper and lower) PM-B (0.006±0.002g) Planetary gear shaft (upper and lower) EM-30L-A Space rack Rack upper side Approx. 35 (greasing range) EM-30L-A Approx. 30 (greasing range)

3. Platen Assy. Bias gear Platen gear (L) Grease the contact face of platen gear (L) and bias gear PM-B

4. Tractor driving mechanism 5. Tractor drive shaft 12345 12345 12345 12345 A-A Arrow view Sliding surface of FG spring and drive shaft end EM-30L-A Drive shaft bearing portion EM-30L-A Drive shaft bearing portion EM-30L-A Change lever Tractor gear bearing portion EM-30L-A Change arm Idle gear teeth EM-30L-A Gear bearing portion EM-30L-A Reset spring Sliding surface of reset spring and gear EM-30L-A Sliding surface of change lever and gear EM-30L-A

6. Pressure roller Release shaft protruding portion - 2 portions EM-30L-A Rear roller holder Shaft Contact portion of rear holder and shaft EM-30L-A Contact portion of support spring and shaft EM-30L-A Sliding portion of release shaft and rear roller holder EM-30L-A Release shaft Front pressure roller Controller holder Sliding portion of rear roller holder and release shaft cam surface (release shaft plane portion) EM-30L-A Bearing portion of front roller holder and pressure roller EM-30L-B Change arm Support spring

7. Pull up roller Assy. Pull-up roller frame Pull-up roller shaft All bearing portions of pull-up roller shaft and pull-up roller frame EM-30L-B Gear and post EM-30L-A

8. Main chassis Assy. Grease portion Grease portion at rib (N: 9 portions) EM-30L-A Grease portion (N: 3 portions) rear side EM-30L-A 9. Carriage Assy. NK2-10-SUS Bearing portion of guide roller EM-30L-B

6. TROUBLESHOOTING AND REPAIR 6.1 Items to Check Before Repair (1) Check the inspection items specified in the instruction manual. (2) Find out as many details of the trouble as possible from the customer. (3) Inspect in the conditions as close as possible to those at the time the trouble occurred. (4) Proceed with the repair as follows: Check the trouble status according to Table 6.1 for the details of the trouble. Then, locate the trouble position according to the detailed flowchart. (5) Carry out a thorough test after the repair to check for correct functioning. 6.2 Troubleshooting Table Table 6.1 Status Trouble Contents Troubleshooting Flowchart No. Surmise of Trouble • Power is not supplied. • No spacing operation 1 2 Power Supply Board, Control Board, Transformer Assy. Space Motor, Carriage Cable, Printhead. • Homing does not end normally. 3 Space Motor, Carriage Cable, Power Supply Board, Control Board, Spacing Mechanism Trouble upon power on • Paper jam while paper insertion 4 Pressure Roller Mechanism, Pull Up Roller Cover. • Smearing/Missing dots 5 Printhead, Control Board, Space Motor, Carriage Cable • Faint or dark print 6 Printhead, Ribbon Feed Assembly, Control Board • Ribbon feed trouble 7 Ribbon Feed Assembly, Space Motor, Control Board • Line feed trouble 8 LF Motor, Platen Assy, LF Mechanism, Control Board • Malfunction of switch on operation panel 9 Operation Panel Board, Control Board • Data receiving failure 0 Control Board, (RS232C I/F Board), I/F Cable, Menu Setting Trouble during printing

ALARM CATEGORY ALARM LED CONDITION CONTENTS TROUBLE SHOOTING ALARM SEL MENU 10CPI 15CPI OPERATOR ALARM Paper end alarm ON OFF — — — From, cut sheet or bottom paper end Set New paper. Paper change lever alarm ON OFF — BLINK 1 OFF Change lever is set to TOP position while paper is already inserted from rear or bottom. • Set the lever to specified position. • Check rear sensor lever. • Replace Control Board Paper jam alarm ON OFF — OFF BLINK 1 • Cut sheet could not be ejected. • Cut sheet could not be fed properly • Remove the paper or check feed Mechanism • Press SEL key. Print Head thermal alarm OFF — BLINK 1 — — Print head temperature exceeds 119°C • Wait until it is cooled. • Replace P.H. or Control Board Space motor thermal alarm OFF — BLINK 1 — — Temperature of space motor exceeds specified value. • It is recovered automatically • Replace SP motor or Control Board FATAL ALARM BLINK 2 OFF OFF See Table 6.3 Hardware Alarm has occurred. See Table 6.3. Note: BLINK1 : 400ms ON, 400ms OFF BLINK2 : 200ms ON, 200ms OFF — : LED is kept in Current Condition (no change) (2) Fault alram display When the printer detects any of the various alarm states, the information is displayed as shown below on the operation panel. The alarm is specified by lamp combination of PRINT QUALITY and CHARACTER PITCH. (See Table 6.3 for details.) Figure 6-1 6.3 Lamp Display (1) Printer mode display Table 6.2

ALARM CATEGORY ALARM LED DISPLAY ALARM 10 12 15 17 20 PROP HSD UTL NLQ REMARKS TROUBLESHOOTING MAIN CONTROL ALARM FIRMWARE DETECTION ALARM SERIAL INTERFACE ALARM MPU internal RAM alarm Program ROM alarm RAM on Control Board alarm EEPROM alarm WDT (Watch Dog Timeout) alarm NMI signal alarm BRK instruction alarm MPU internal RAM alarm ROM alarm RAM on I/F board alarm I/F not mounted Read/write error Check sum error Read/write error No reaction when MPU reads data MPU is locked up and it ios reset after 65ms. NMI port of MPU is kept low level. FFFF data is detected due to MPU locked up. Read/write error Check sum error Read/write error No reaction from serial I/F board Replace Control Board Replace ROM or Con- trol Board Replace Control Board Replace Control Board Turn the power OFF and ON or replace Control Board Turn the power OFF and ON or replace Control Board Replace ROM or Con- trol Board Replace RS232C I/F Board Replace RS232C I/F Board Replace RS232C I/F Board Replace RS232C I/F Board or Control Board. : LED Blink (200ms ON, 200ms OFF) : LED Lights up (3) Fatal Alarm Table 6.3 (1/2)

ALARM CATEGORY ALARM LED DISPLAY ALARM 10 12 15 17 20 PROP HSD UTL NLQ REMARKS TROUBLESHOOTING SPACING ALARM Spacing alarm Print Head homing alarm Print Head A/D alarm Space IPT is not occurred within in specified timing. : LED Blink (200ms ON, 200ms OFF) : LED Lights up PRINT HEAD ALARM Print Head Gap A/D alarm • Replace space motor. • Replace P.H. cable. • Replace Control Board • Check the mechanisms if load is too much. • Check the P.H. connection. • Replace Print Head. • Replace P.H. cable. • Replace Control Board Print head does not reach to the home position. Thermister is open, short with 0V or short with +5V. Print Head Gap Signal open. • Replace P.H. cable. • Replace Space Motor Assy. • Replace Control Board SP motor A/D alarm Thermister is open, short with 0V or short with +5V. • Replace P.H. cable. • Replace Space Motor Assy. • Replace Control Board FAN alarm FAN motor does not rotate. • Replace Control Board • Replace FAN motor. Table 6.3 (2/2)

Switch AC connector Power Supply Board Transformer Centro-connector Space motor LF motor FAN motor Print head Control Board Operation Panel Board

6.4 Connection Circuit Check for Printhead and SP/LF Motor (1) Printhead Signal Connector pin number CN1 1 #1 2 #2 3 #4 4 #6 5 #8 6 7 8 9 10 11 #9 12 #7 13 #5 14 #3 15 Thermistor (5KΩ at 25°C) HEAD1 HEAD2 HEAD4 HEAD6 HEAD8 0V HTEMP +50V +50V +50V HEAD9 HEAD7 HEAD5 HEAD3 NC