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Sharp AR-5132 Service Manual
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Sharp AR-5132 Service Manual

Sharp AR-5132 Service Manual

Digital copier no.2
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[ 1 ] PRINCIPLES OF THE DIGITAL COPIER . . . . . . . . . . . . . . . . . . . 1-1
[ 2 ] PROCESS SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
[ 3 ] DEVELOPING SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
[ 4 ] PAPER FEED SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
[ 5 ] TRANSPORT AND FUSING SECTION . . . . . . . . . . . . . . . . . . . . 5-1
[ 6 ] HIGH VOLTAGE SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
[ 7 ] RADF MECHANISM SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
[ 8 ] DESK UNIT MECHANISM SECTION . . . . . . . . . . . . . . . . . . . . . . 8-1
[ 9 ] ELECTRICAL SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
[10] RADF ELECTRICAL SECTION . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
[11] DESK UNIT ELECTRICAL SECTION . . . . . . . . . . . . . . . . . . . . . 11-1
Parts marked with "!" is important for maintaining the safety of the set. Be sure to replace these parts with specified
ones for maintaining the safety and performance of the set.
SERVICE MANUAL
DIGITAL COPIER NO.2
MODEL
CONTENTS
SHARP CORPORATION
CODE: 00ZAR5132TM1E
AR-5132
This document has been published to be used
for after sales service only.
The contents are subject to change without notice.

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  • Page 1 SERVICE MANUAL CODE: 00ZAR5132TM1E DIGITAL COPIER NO.2 AR-5132 MODEL CONTENTS [ 1 ] PRINCIPLES OF THE DIGITAL COPIER ....1-1 [ 2 ] PROCESS SECTION ........2-1 [ 3 ] DEVELOPING SECTION .
  • Page 2 CAUTION This copier machine is a class 1 laser product that complies with 21CFR 1040.10 and 1040.11 of the CDRH standard and IEC825. This means that this machine does not produce hazardous laser radiation. The use of controls, adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.

  • Page 3: Table Of Contents

    CONTENTS [ 1 ] PRINCIPLES OF THE DIGITAL [ 7 ] RADF MECHANISM SECTIONS ..7-1 COPIER ......1-1 1.

  • Page 4: Principles Of The Digital Copier

    [1] PRINCIPLES OF THE DIGITAL COPIER Copy lamp section Digital machine 1. Difference in structure from analog copiers Scanner section Analog machine Copy lamp section Laser section Drum Printer section Drum The digital copier is composed of the scanner section and the printer section.

  • Page 5: Scanner Section

    (1) Basic operations of copying (2) Basic structure of the scanner section The scanner unit is the scanning section of the digital optical system. Image data are scanned in the scanner section and sent to the The light from the halogen lamp (which is driven by the DC power to image process (ICU) PWB.
  • Page 6 LSU internal structure a ≠ b ≠ c d = e = f f Θ lens 3 BD PWB Convergence Mirror lens for BD Polygon f Θ lens 2 motor f Θ lens 1 f Θ LENS Mirror for BD Polygon motor fan drive PWB...

  • Page 7: Image Process Section

    5. Image process section Data flow (flowchart) Content <Lamp light quantity adjustment> <Lamp light quantity adjustment> 1. Halogen lamp (145W) Halogen lamp (ON) The lamp is lighted by the DC power under the reference white plate. 2. 400dpi reduction line sensor (CCD) The sensor receives the reflected light as photo energy from the shading plate (refer- ence white plate), and converts it into electrical energy (analog voltage).
  • Page 8 Data flow (flowchart) Content <White level correction> <White level correction> 15. Halogen lamp Halogen lamp <ON> For white level correction, the halogen lamp is lighted at the voltage obtained in the light quantity adjustment under the shading plate and the shading plate is scanned. 16.
  • Page 9 Data flow (flowchart) Content 28. FIFO Image data of one line are stored in the line memory (FIFO). This FIFO is for zooming. For reduction, the scanned image data are thinned out when they are written into the FIFO. For enlargement, the scanned image values are used as the values of plural pixels of the next one.
  • Page 10 Data flow (flowchart) Content 30. FIFO This line memory (FIFO) is used for area separation and MTF correction. 31. Gate array 2 Performs area separation. In area separation, the characteristics of the target pixel and the neighboring pixels are judged to perform the optimum process. For example, judge- FIFO ment is made to identify that the area is a photo area or a hatched area such as newspaper photos.
  • Page 11 (2) Image process section The image process section is composed of gate arrays A and B, the The CPU performs register setting and rewriting of LUT (look up CPU, and memories (SRAM, FIFO, EPROM). Gate array A forms table) every time when the user changes the mode. It also calculates data for shading correction and calculates histogram data for auto- the correction value of shading correction.
  • Page 12 [MTF correction] Pin name Function XIFADR0 When the characteristic value outputted from gate array B is inputted Data bus to set the built-in register. to the address of multi-function LUT, data which show the charac- teristics of the peripheral pixels are outputted from the multi-function XIFADR5 LUT.
  • Page 13 Gate array B Pin name Function Signal showing the effective image Pin arrangement table AREALDLY area which is behind from AREA Pin name Function signal by 4 clocks. LOW active. Clock signal input pin. Clock of CLK2 16MHz is inputted. Data read signal to the built-in AIN0 XIFRD...

  • Page 14: 2 ] Process Section

    [2] PROCESS SECTION Light (Laser) Dark area Dark area (OPC drum, cleaning unit) 1. Outline Base The indirect electrostatic copiers use normal paper for copying, and form electrostatic latent images on the OPC drum surface which can be used repeatedly, develop them into visible images (toner images), Principle of photoconductor (conductivity) and transfer them on copy paper.
  • Page 15 Characteristics of organic photoconductors (OPC) [Acceptance potential] • The dark resistance of the photoconductor layer decreases as the Can be formed into various shapes (drum, sheet, belt) electric field applied between layers increases. • High insulation in a dark place. (Acceptability and retainability of When the photoconductor is charged, the electric field is formed to a charges) high level and the resistance of the layer decreases to restrict the...

  • Page 16: Basic Process And Composition

    2. Basic process and composition • This machine employs the scorotron system to charge the Screen grid photoconductor surface uniformly to a certain level. The conven- tional corona charger mechanism is employed which is composed Main charger output of the corona wire and the saw tooth plate (stainless plate of section 0.1mm thick).
  • Page 17 Step 4: Transfer Step 7: Discharge The visible images on the drum surface are transferred to copy The discharge lamp light is radiated to the drum to reduce the electric paper. Positive corona of the transfer charger is applied to the back of resistance of the OPC layer, eliminating the residual charges.
  • Page 18 (4) OPC drum sensitivity reduction correction (New) (After use) In the AR-5132, deterioration of copy quality is prevented by correc- Wear tion with the charging grid voltage against the potential reduction of the OPC drum due to repeated use. The drum wear increases the grid voltage to maintain the drum sur- face potential at a constant level, and the apparent sensitivity of the OPC drum is decreased.
  • Page 19 The developing bias voltage is obtained from comparison with the standard patch density. In the AR-5132, toner patch images are formed at the same position on the OPC drum to improve accuracy of the process control. That is, a marking is provided on the drum, and the marking point is sensed and toner patch images are formed at a certain position.

  • Page 20: 3 ] Developing Section

    2. Basic composition [3] DEVELOPING SECTION 1. Basic outline (1) Two-component developer Developer is composed of tow components; toner and carrier. Carrier functions as a media to attract toner to electrostatic latent images on the OPC drum. As the toner is mixed with the carrier, the friction changes it to posi- tive or negative.

  • Page 21: 4 ] Paper Feed Section

    [4] PAPER FEED SECTION 1. Basic outline The AR-5132 employs the font loading system and the multi paper feed table which can be stored inside the machine, cutting the instal- lation space. It is also equipped with the two-step trays, the 3000- sheet LCC tray, and the manual paper feed tray which allows con- tinuous feeding of 50 sheets as standard provisions.

  • Page 22: Basic Operation

    3. Basic operation When the manual paper feed clutch sleeve pawl C is caught by the manual feed latch, the manual fed stopper falls and the manual feed pick-up roller rises. At the time, the transport roller is (1) Manual paper feed section operations rotating.
  • Page 23 The manual paper feed solenoid is turned on for 0.08 sec in Lift up synchronization with rotation of the resist roller, and the manual When the power is turned on, the main circuit checks the sensors. peper feed roller is rotated. Therefore, paper jams due to insuffi- The lift up motor is turned on/off to make ready for paper feed cient pick-up of the resist roller is prevented.

  • Page 24: 5 ] Transport And Fusing

    Fusing unit 1. Outline MG roller Cleaner unit Suction unit Reverse roller The AR-5132 allows paper transport of max. A3 (11" × 17") to min. A5 (8 1/2" × 5 1/2"). PS roller Paper exit roller Multi paper ADU drive unit...

  • Page 25: 7 ] Radf Mechanism Sections

    ↓ [7] RADF MECHANISM SECTIONS Step 10: Reverse sensor (RDD) senses the lead edge  of the discharged document.  (RDD output HIGH)  ↓ 1. Operation flowchart Step 11: Document feed sensor (DFD) senses the The figures below show the transport path of an document from the ...
  • Page 26 * C Step 24: Paper feed solenoid (DFSOL) OFF Step 38: Paper feed motor (DFM) forward rotation   (The weight plate and the stopper move up.) (Paper feed roller, semi-circular roller   rotation)   * C: If there is no document on the ...
  • Page 27 Step 53: Reverse motor (DRM) reverse rotation Step 66: Reverse sensor (RDD) senses the lead edge   (Reverse roller, paper exit roller rotation) of the discharged document.   The document is transported to the paper (RDD output HIGH) ...

  • Page 28: Document Size Detection

    ↓ 2. Document size detection Step 82: Transport motor (DTM) forward rotation  The document size is detected in three ways of different purposes. (Transport belt rotation)  Reverse motor (DRM) forward rotation   (Reverse roller, paper exit roller rotation) 1) Document size detection by the document set ...
  • Page 29 2) Document size detection by the document width 3) Document size detection by the paper feed sensor (DWS) in the paper feed section motor rotation sensor (DFMRS) The document size detection by the document width sensor (DWS) in This function compensates for the inaccuracy of the document size the paper feed section is used in automatic paper size and automatic recognition in the document tray when documents of different sizes magnification ratio selection mode to determine whether the docu-...

  • Page 30: 8 ] Desk Unit Mechanism Section

    [8] DESK UNIT MECHANISM SECTION 1. Operation flow chart A. Paper tray 2 (Normal copy mode)  ↓ Paper feed start <Copier print switch ON> ↓ STEP 01: JOB command start command reception command → To STEP 02  • Transport motor ON ↓...
  • Page 31 B. Paper tray 3  Paper feed start <Copier print switch ON> ↓ ↓ STEP 01: JOB command start command reception Preliminary  → To STEP 09 • Transport motor ON paper feed end  ↓ command STEP 02: Paper feed request reception (Preliminary ...

  • Page 32: 9 ] Electrical Section

    [9] ELECTRICAL SECTION 1. Block diagram 9 – 1...

  • Page 33: Icu Pwb

    In the A/D conversion, by turning off the shading correction data, the 2. ICU PWB CCD element fluctuation and the optical system (lamp, lens) light quantity fluctuation are corrected, and the analog data are converted (1) CCD control section into 8-bit digital data between the white level and the black level. Basic functions The 8-bit image data converted in the even and the odd circuits are stored in FIFS by one pixel at one time alternately.
  • Page 34 Block diagram [CCD GA and peripheral circuit] The CCD control GA and the peripheral circuit are connected as ∅ RS-EVEN ∅ LH-EVEN ∅ 2-EVEN ∅ 1-EVEN shown in the figure on the next page. [CCD GA functions] The CCD GA functions are classified as follows: VOUT-EVEN Output amplifier A.
  • Page 35 <Timing chart> ΦROG Φ1-ODD Φ1-EVEN ΦLH-EVEN ΦLH-ODD Φ2-ODD Φ2-EVEN ΦRS-ODD ΦRS-EVEN VOUT-ODD D23 D25 D27 D69 D71 D73 D77 D79 D81 S5145 S5149 S5147 VOUT-EVEN D24 D26 D28 D70 D72 D76 D78 D80 S5146 S5150 S5148 Dummy signal (74 pixels) Dummy signal (20 pixels) 1 line output period (5244 pixels) The dark area is divided into the odd number pixels and the even...
  • Page 36 (2) Image process section Operational description Image signals processed in the image process section are stored in The image process section is composed of gate array A and gate the FIFO as the line image signals and inputted to the LCU G/A. The array B, the SRAM for peripheral table, and the FIFO.

  • Page 37: Pcu Pwb

    3. PCU PWB (1) Block diagram (PCU PWB) 9 – 6...
  • Page 38 Major functions (2) Main CPU (IC107: H8/570) • ISP (Built in the EPROM) Outline • SCI (Serial communication interface) The CPU controls the loads in the body and sends and receives data to and from the various optional controllers through the serial data •...
  • Page 39 Internal block diagram Port 1 Bus control Data buffer EXTAL Clock oscillator XTAL Wait state RAM 2KB controller Interruption controller STBY P50/A16 Data transfer H8/500 P51/A17 controller P52/A18 P53/A19 P54/IRQ0 P56/E RAM timer P57/ADTRG Watch dog P60/PW0 timer P61/PW1 P127/D15 Serial P62/PW2 P126/D14...
  • Page 40 CPU pin signals Pin No. Port Signal name In/Out Specification TXD SUB Serial data output to SUB CPU RXD SUB Serial data input from SUB CPU TXD ICU Serial data input to ICU RXD ICU Serial data output from ICU RES SUB Reset signal to SUB CPU RES OPE...
  • Page 41 Pin No. Port Signal name In/Out Specification Address signal Address signal Address signal Address signal Address signal Address signal Address signal Address signal Address signal — — — Not used. — — — Not used. — — — Not used. —...
  • Page 42 PLASTIC The RAM stores various setting data required for operations of the CERDIP AR-5132 system, causes of paper jams, and the counter data such FLAT PACK as trouble codes. (Batteries are not required.) Data transmission is performed between the RAM and the main PWB immediately after turning ON or OFF the power.
  • Page 43 (3) Start/stop control circuit Operation a. POFA generation circuit (Power voltage detection circuit) Outline This circuit detects ON/OFF of the power and the power voltage. The ON/OFF state of the power is detected to control start/stop of The Immediately after turning on the power, when the AC input each circuit.
  • Page 44 b. RESET generation circuit e. Operations at instantaneous service interruption The RESET signal is formed by the power voltage detection signal Since the POFA signal is outputted from IC206, the POFA signal (POFA) and the data transfer complete signal (DCH) from the may be erroneously delivered due to the difference in rising time CPU.
  • Page 45 When a paper jam occurs in the AR-5132, the control circuit operates for max. 3 minutes to shorten the jam recovery time (8sec). IC104...
  • Page 46 [When the heat roller surface temperature becomes higher than the set level] Stepping motor time chart a. Since the thermistor pin voltage is lower than the set level, the output signal HL from the CPU becomes LOW. b. The HL signal becomes LOW, SSR is OFF, the external triac is OFF, and the heater lamp is OFF.

  • Page 47: Operation Section

    4. Operation section (1) Outline The operation circuit is composed of the key matrix circuit and the display circuit. Besides, communication with is made with the IR unit. Block diagram OP control PWB VC (+12V) S IN S OUT Key matrix STROBE CLK LATCH VD (+5V)

  • Page 48: Lcd Display Section

    5. LCD display section (1) Block diagram Counter AUDCL AUDCP Auditor AUDO AUDRD DATA D0 ~ D7 +12V A0 ~ A15 Driver GND2 IC315 +24V A-RAM IC304,329 -20V V-RAM GND1 Buffer Buffer PRO- RXD-OP IC301 A0 ~ A12 IC306 DSR-OP Driver GRAM TXD-OP...
  • Page 49 CPU (IC322) pin signals Signal Signal In/Out Function In/Out Function name name Data read signal Key input data Address signal Key input data Address signal Key input data Address signal TXD-OP Main communication (serial data output) Address signal RXD-OP Main communication (serial data input) Reset signal input from the main body LED clock RESET...
  • Page 50 (3) ROM (4) Outline of LCD display control operations Outline The CPU receives image data from the main body. (Besides, the key LED data are received.) A. Program ROM (IC314) With the received image data (corresponding to the data ROM B.
  • Page 51 9 – 20...
  • Page 52 (5) LCD controller (IC322) Signal Signal In/Out H/L Function In/Out H/L Function name name Character generation character out Stroke signal for the CPU to read/write data F (WR) from/to the internal register of the LCD controller. Character generation character out data Controls data transmission direction 42 R/W (RD)

  • Page 53: Dc Power Circuit

    6. DC power circuit (1) Block diagram This power circuit is composed of the main section and the copy lamp section. The AC power is rectified by the main section, and switching- transformed by the DC/DC convertor, and rectified and smoothed again to provide DC power voltages of the loads.
  • Page 54 Power Rush current Rectifying/ Chopper Rectifying/ ACin relay Noise filter limit circuit smoothing circuit smoothing (S701) Drive Current Transformer transformer transformer CL output (T704) (T702) (T703) Main Overcurrent sectoin Regulator Control protection circuit circuit (PC707) circuit ON/OFF CL monitor CLPR CLMON control circuit...
  • Page 55 c. Rectifying/smoothing circuit In this circuit, he AC voltage (50/60Hz) is rectified by the rectifier Q701(Q702) diode (D701) and smoothed by the smoothing capacitors (C707, Gate < > Source voltage (VGS) C708). The solid line and the dotted line in the figure below show the flowing path of the charging current.
  • Page 56 g. Overcurrent protection circuit The d line of the primary side is connected to the detecting resistor TOP VIEW of the primary side current. When an overcurrent is generated, the +IN1 16 +IN2 current in the switching FET (Q701, Q702) is detected and a signal is sent to the control IC (IC701) to reduce the ON pulse width of the -IN1 15 -IN2...
  • Page 57 j. FW signal The AC input voltage is full-wave rectified by D704 ~ D707. Byturning ON/OFF Q703, the photo coupler is synchronized to performON/OFF operations. This signal synchronized with the AC voltage waveform is transmitted to the secondary side by the photo coupler to turnON/OFF Q704 similarly, providing the FW signal synchronized withthe AC voltage waveform.
  • Page 58 k. Overvoltage protection circuit When each output (excluding –5.2V and –20V series) becomes an overvoltage, the over voltage protection circuit of each output trans- mits a signal through the photo coupler (PC702) to the primary side control circuit, and the invertor operation is stopped by stopping the switching operation of IC701, preventing each output voltage from rising.
  • Page 59 [Waveform of each section] Condition: Input 100V, 50Hz rated load 3.1V 260V 22µs 3.0µs 8.4µs Fig. 23 IC7065 Pin PSC waveform Fig. 18 Q701(Q702) drain-source voltage waveform 3.2V 5.0µs 22µs Fig. 24 IC701 Pin OSC waveform Copy lamp (CL) section Fig.
  • Page 60 b. Rush current limit circuit Similarly to the main section, the circuit shown below limits the rush current which flows into the smoothing capacitor (C792) when the power is supplied. D768 ERA9102 R7053 R7054 R7040 C7017 47(1W) 47(1W) TR702 0.01/50V(RPE) R7045 C795 C796...
  • Page 61 e. Overvoltage protection circuit When an overvoltage is generated in the copy lamp section, it is detected by the overvoltage detection circuit to turn off the power relay (S701) to stop the operation of the copy lamp. The operation is of the latch system. After removing the overvoltage, supply the AC power to reset.
  • Page 62 g. CLMON signal This signal monitors the CL output voltage. ON (lighted) at HIGH, and OFF at LOW. PC707 R7092 R7101 R7103 4.7K 2.2K 4.7K PS2561 T704 N-T01-014 CLMON CN710-1 R7049 Lighting H 1K(1/2W) Lighting LO R7050 1K(1/2W) D765 RD16ESAB2 PC708 RET (MAIN PWB) CN707-2...

  • Page 63: Radf Electrical Section

    [10] RADF ELECTRICAL SECTION 1. General This circuit controls feeding, stopping, and reversing of the document. It is composed of sensors, switches, the circuit which processes signals from the copier PPC, the circuit which drives motors, solenoids, and clutches, the CPU, the G/A and its peripheral circuits. 2.

  • Page 64: Operations

    3. Operations A. Sensor input circuit [a] Document timing sensor (DTD) The document timing sensor is a reflection type sensor, and the LED and the photo transistor are integrated into one. Infrared light emitted from the LED is reflected by the mirror on the opposite side, and the reflected light enters the photo transistor to increase the photo current in the photo transistor, detecting "No document."...
  • Page 65 [b] Document feed sensor (DFD) The document feed sensor is a reflection type sensor, and the LED and the photo transistor form a pair. Infrared light emitted from the LED is reflected by the mirror on the opposite side, and the reflected light enters the photo transistor to increase the photo current in the photo transistor, detecting "No document."...
  • Page 66 [c] Reverse sensor (RDD) The reverse sensor is a reflection type sensor, and the LED and the photo transistor are integrated into one. Infrared light emitted from the LED is reflected by the mirror on the opposite side, and the reflected light enters the photo transistor to increase the photo current in the photo transistor, detecting "No document."...
  • Page 67 [d] Paper feed motor rotation sensor (DFMRS) This sensor senses rotation of the paper feed motor, and is composed of the photo interrupter built in the amplifier and the slit disc attached to the motor shaft. The pulse signals corresponding to the motor speed are obtained. the motor rotation speed is sensed from the frequency of the pulse signals, and the motor rotation amount is sensed by counting the pulse numbers.
  • Page 68 [f] Document set sensor (DSS) The DSS uses a photo interrupter which is integrated with a light emitting diode and a photo transistor. The signal is passed through the noise filter composed of R23, C16, and Schmidt trigger invertor (IC4) to the gate array (IC7 53 pin), then passed through the data bus to the CPU. R101 TLP1240(C5) (IC7)
  • Page 69 B. Solenoid drive circuit [a] Paper feed solenoid (DFSOL), reverse solenoid (DRSOL) drive circuit This circuit drives the weight plate which presses the bundle of documents on the tray, the paper feed solenoid which drives the paper feed section shutter, and the reverse solenoid which drives the reverse guide to lead an document to the reverse path when reversing. The basic composition is the same.
  • Page 70 [b] Reset circuit This circuit generates reset signals for the CPU and the external G/A, and is composed of IC6 and its peripheral circuits. IC6 is provided with the reset function activated when the power is turned on and when the power falls below +5V. The reset state is maintained until a certain time passes from when the power voltage reaches about 4.3V after supplying the power.
  • Page 71 [d] Transport motor (DTM) drive circuit This circuit controls the transport motor rotation/stop, the rotating direction, and the motor current. It is composed of the CPU (IC11), the constant current chopper system driver IC (IC8), and the G/A (IC7). The motor rotating speed and the rotating direction are controlled with the stepping motor drive excitement pattern signals from the CPU (12 ∼ 15 pins).
  • Page 72 [f] Paper feed motor (DFM) current limiting circuit This circuit limits the motor start current to a constant level, and is composed of the resistor for detection of the current value and the voltage comparator. The negative voltage side of the paper feed motor is connected to the;pickup resistor composed of R97, R98, and R99, which converts the current flowing in the driver circuit into a voltage value.

  • Page 73: Desk Unit Electrical Section

    [11] DESK UNIT ELECTRICAL SECTION 1. Outline This circuit controls paper feed to the copier body, and is composed of sensors, switches, the circuit to interface with the copier, the circuit to drive motors, clutches, and solenoids, the CPU, and its peripheral circuits. 2.

  • Page 74: Operational Descriptions

    3. Operational descriptions (1) Sensors/detectors input circuit A. Paper pass sensors (PPS0 ∼ PPS2, EMP) input circuit The paper pass sensors are positioned in the paper transport path and used to detect paper pass. They are reflection type sensors. A sensors is composed of an LED and a photo transistor.
  • Page 75 C. Lift motor rotation sensor (E1CLK, E2CLK), remaining amount sensor (RESTR,F), side sensor input circuit The lift motor rotation sensor senses rotation of the lift motor, and it is composed of the slit disc attached to the rotating shaft of the lift motor and the photo interrupter.
  • Page 76 F. Open/close switch (F/LSW) input circuit This circuit is composed of the microswitch which detects open/close of the paper tray 3 and the mechanism to press the switch. When the tray is closed, the switch is turned on. When the tray is opened, the switch is turned off. When the switch is turned on, +24V is applied to the cathode of ZD2 to supply current to the base of Q9, turning on Q9 and driving F/LSW signal LOW (0V).
  • Page 77 a. Coil select sensor H1, 2, 3 are the magnetism sensitive elements (Hall element) used to determine the polarity of the main flux generated when the rotor rotates, producing the coil conduction select signal. b. Coil select control circuit The coil select signal (weak analog value around 2.5V)produced by H1, 2, 3 is converted into the HIGH/LOW level judgement signal in the IC1. The table below shows the logic diagram of IC1.
  • Page 78 B. Lift motor drive circuit (E1MOT, E2MOT) The lift up motor is rotated to lift the paper in the paper tray 3 to the transport level. The lift motor drive circuit drives the lift motor. There are two sets of the lift up mechanism, each one is provided with the motors (E1MOT, E2MOT) and the drive circuit. These two are of the same composition. In the following description, the E1MOT is described.
  • Page 79 D. Other circuits (a) Reset circuit The reset signal generates the CPU reset signal, and is composed of the IC5 and the peripheral circuits. The IC5 has the integrated reset functions of the power ON reset, the CPU reset in case of abnormally low voltage of +5V, and the watch-dog timer function. When the power is supplied and the power line (+5V) reaches about 0.8V, the IC5 start operation.

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