Ricoh FT 3013 Service Manual

IMPORTANT SAFETY NOTICES

PREVENTION OF PHYS ICAL INJURY

1. Before disassembling or asse mblin g pa rts of the copie r and perip herals, make sure that the copier power cord is unplu gg ed.

2. The wall outlet should be near the copier an d easily accessible.

3. Note that the optio na l a nt i-con de nsation heaters are supplied wit h electrical voltage even if the main switch is turned off .

4. If any adjustment or operat ion check ha s to be made with exterior covers off or open while the main switch is turned on, kee p ha nds away from electrified or mechanically drive n comp on ents.

5. The inside and the met al pa rts of the fusin g un it be come extremely hot while the copier is operat ing . Be careful to avoid touching those components with your bare hands.

6. When the development unit, cleaning unit, drum unit, or the DF is removed from the machine, the upper unit becomes lighter. If th e up per unit is released under this condition, it tends to open very abrupt ly. The service engineer might be injured if he is leaning over the machine at this time. Also, the machine might move due to the shock of the up pe r unit opening abruptly. To avoid possib le inju ry o r machine damage, hold the upper unit firmly when opening the unloaded upper unit.

7. Due to variation in the tolerance of the torsion springs, the upper unit cannot be held at an angle of 16 deg rees by itself when the DF is installed. To avoid possible injury, always use the upper unit stand to keep the upper unit op en.

HEALTH SAFETY CONDITIONS

1. Never operate the copier without the ozon e filt er inst alle d.

2. Always replace the ozone filter at 80K copy intervals.

3. Toner and developer are non-to xic, bu t if you get eith er of them in your eyes by accident, it may cause temp ora ry e ye disco mfo rt. Try to remove with eye drops or flush with wat er as first aid. If un succe ssfu l, ge t med ical attention.

OBSERVANCE OF ELECTRICAL SAFETY STANDARDS

1. The copier and its peripherals must be insta lled and maintained by a customer service represen tative who has completed the training course on those models.

– CAUTION –

2. The RAM pack has a lithium battery which can explode if handled incorrectly. Replace only with same RAM pa ck. Do not recharge, or burn this battery. Used RAM pack must be handled in accord ance with local regulations.

SAFETY AND ECOLOGICAL NOTES FOR DISP OS AL

1. Do not incinerate the toner cartridge or the used toner. Toner dust may ignite suddenly when exposed to open flame.

2. Dispose of used tone r, developer, and organic photoconductors according to local regulations. (These are non-toxic supplies.)

3. Dispose of replaced parts in acco rda nce with local regulations.

4. When keeping used lithium batteries (main control boards) in order to dispose of them later, do not store mo re th an 100 batte ries (main control boards) per sealed box. Storing larg er nu mbe rs or n ot sealing them apart may lead to chemical reactions and heat build -up .

SECTION 1

OVERALL MACHINE

INFORMATION

24 June 1994 SPECIFICATIONS

1. SPECIFICATIONS

Configuration : Desk top Copy Process: Dry electrostatic transfer system Original Type: Sheet/Book Original Alignment: Left center Original Size: Maximum: A3/11" x 17" (lengthwise) – A152

copier B4/10" x 14" (lengthwise) – A151 copier

Copy Paper Size: Maximum: B4/10" x 14" (lengthwise)

Minimum:

Paper Tray: A5/51/2" x 81/2" (lengthwise) Bypass Feed: A6/51/2" x 81/2" (lengthwise)

Copy Paper Weight: Paper tray feed – 64 to 90 g/m2 (17 to 24 lb)

Bypass feed – 52 to 105 g/m2 (14 to 28 lb)

Reproduction Ratios: 2 Enlargement and 3 Reduction (A152 copie r only)

A4 Version Letter Version

Enlargement

Full size 100% 100%

Reduction

Zoom: From 61% to 141% in 1% steps

(A152 copier only)

Copying Speed: 13 copies/minute (A4 /81/2" x 11" lengthwise)

10 copies/minute (B4/81/2" x 14") Warm-Up Time: 30 seconds (at 20°C/68°F) First Copy Time: 9 seconds (A4/81/2" x 11" lengt hwise)

141% 122%

93% 82% 71%

129% 121%

93% 74% 65%

Copy Number Input: Number keys, 1 to 99 Manual Image Density

Selection:

7 steps

1-1

SPECIFICATIONS 24 June 1994

Automatic Reset: 1 minute standard setting; can also be set to 3

minutes or no automatic reset. Energy Saver Function: Automatic Paper Capacity: Paper tray – 250 sheets

Bypass feed table – 1 she et Toner Replenishment: Cartridge exchange (320 g/cartridge) Copy Tray Capacity: 100 sheets (B4/10" x 14" or smaller) Power Source: 110V / 60 Hz/ 15A (for Taiwan)

115V/ 60Hz/ 15A (for North America)

220V – 240V/ 50Hz/ 8A (for Europe)

220V/ 60Hz/ 8A (for Middle East)

220V/ 50Hz/ 8A (for Asia)

(Refer to the serial number plate (rating plat e) to

determine the power source required by the

machine.) Power Consumption:

Noise Emission:

Dimensions:

Copier with platen cover and

copy tray

Copier with document feeder

and copy tray

Copier Only With DF Maximum 1.4 kVA 1.5 kVA Warm-up 620 VA (average) 640 VA (average) Copy cycle 810 VA (average) 860 VA (average) Ready 160 VA (average) 180 VA (average)

Copier Only With DF Maximum 58 db 60 db Copy cycle Less than 55 db Less than 55 db Ready Less than 39 db Less than 39 db

Width Depth Height

713 mm (28.1") 592 mm (23.3") 400 mm (15.7")

713 mm (28.1") 592 mm (23.3") 463 mm (18.2")

1-2

24 June 1994 SPECIFICATIONS

Weight: Copier only: 43 kg (94.8 lb)

With DF: 50 kg (110.2 lb)

Optional Equipment: (Sales items)

Optional Equipment: (Service items)

Document feeder (A152 copier only) Key counter

Drum anti-condensation heater Optics anti-condensation heater Pre-transfer lamp Optics cooling fan (for A151 copie r only)

• Specifications are subject to change witho ut notice.

1-3

COPY PROCESSES AROUND THE DRUM 24 June 1994

2. COPY PROCESSES AROUND THE DRUM

2. EXPOSURE

1. DRUM CHARGE

3. ERASE

8. QUENCHING

4. DEVELOPMENT

7. CLEANING

6. PAPER SEPARATION

5. IMAGE TRANSFER

1-4

24 June 1994 COPY PROCESSES AROUND THE DRUM

1. DRUM CHARGE

In the dark, the charge corona unit gives a uniform negative charge to the organic photoconductive (OPC) drum. The charge remains on the surface of the drum because the OPC drum has a high electrical resistance in the dark.

2. EXPOSURE

An image of the original is reflected to the OPC drum surface via the optics assembly. The charge on the drum surface is dissipated in direct proportion to the intensity of the reflected light, thus producing an electrical latent image on the drum surface.

3. ERASE

The erase lamp illuminates the areas of the charged drum surface that will not be used for the copy image. The resistance of the drum in the illuminated areas drops and the charge on those areas dissipates.

4. DEVELOPMENT

Positively charged toner is attracted to the negatively charged areas of the drum, thus developing the latent image. (The positive triboelectric charge is caused by friction between the carrier and toner particles.)

5. IMAGE TRANSFER

Paper is fed to the drum surface at the proper time so as to align the copy paper and the developed image on the drum surface. Then, a strong negative charge is applied to the back side of the copy paper, producing an electrical force which pulls the toner particles from the drum surface to the copy paper. At the same time, the copy paper is electrically attracted to the drum surface.

6. PAPER SEPARATION

A strong ac corona discharge is applied to the back side of the copy paper, reducing the negative charge on the copy paper and breaking the electrical attraction between the paper and the drum. Then, the stiffness of the copy paper causes it to separate from the drum surface. The pick-off pawl help to separate the paper from the drum.

7. CLEANING

The cleaning blade removes any toner remaining on the drum.

8. QUENCHING

Light from the quenching lamp electrically neutralizes the surface of the drum.

1-5

COPY PROCESS CONTROL 24 June 1994

3. COPY PROCESS CONTROL

Image Density Control

Toner Density Detection

Residual Voltage (Vr) Detection

Between Copies

Grid Voltage

Standard image density grid voltage (–680 V)

+ + + Drum residual voltage

(Vr) correction factor (SP67) +

Auto image density level factor (SP34)

Standar d ID sensor grid voltage (–460 V) +

Drum wear correction factor (SP57)

Standar d ID sensor grid voltage (–460 V) + Drum wear correction factor (SP57)

0 Volts (Fixed) Exposure lamp tu rns off –160 Volts (Fixed)

Exposure Lamp

Voltage

Base exposure lamp voltage (Manual or ADS mode) (SP48)

L correction factor

+ Reproduction ratio correction factor (A152 copier on ly)

Same as image density control

Development Bias

Voltage

Base bias voltage factor (Manual or ADS mode [SP34])

Image bias voltage adjustme nt factor (SP37)

+ Drum residual voltage (Vr) correction factor

Note: Base bias voltage at manual ID level 7 can be adjusted by SP50

Depends on I D sensor bias setting (SP33)

Note: For initial 499 copies bias voltage is increased by –20 volt s

0 Volts (Fixed) Full erase

Image bias voltage adjustme nt factor (SP37)

+ Drum residual voltage (Vr) correction factor

Erase Lamp

Depends on paper size and reproduction ratio

ID sensor pattern erase (Vsg detection: Full erase)

(All LEDs ON)

Full erase (All LEDs ON)

NOTE: The boxed items can be adjusted by SP mode.

1-6

24 June 1994 MECHANICAL COMPONENT LAYOUT

4. MECHANICAL COMPONENT LAYOUT

21 22 23

24 25

32 33

1. Semicircular Feed Rollers

2. Paper Tray

3. Registration Rollers

4. Transfer and Separation Corona Unit

5. Pick-off Pawl

6. Cleaning Unit

7. Pressure Roller

8. Fusing Unit

9. Hot Roller

10. Exit Rollers

11. Copy Tray

12. Hot Roller Strippers

13. Exhaust Blower Motor

14. 3rd Mirror

15. 2nd Mirror

16. 1st Mirror

17. Ozone Filter

18. Used Toner Tank

19. Cleaning Blade

20. Quenching Lamp

21. Charge Corona Unit

22. Lens

23. 6th Mirror

24. Erase Lamp

25. Drum

26. 4th Mirror

27. 5th Mirror

28. Optics Cooling Fan Motor (A152 Copier only)

29. Toner Supply Unit

30. Development Unit

31. 2nd Relay Rollers

32. By-pass Feed Table

33. 1st Relay Rollers

1-7

ELECTRICAL COMPONENT LAYOUT 24 June 1994

5. ELECTRICAL COMPONENT LAYOUT

17 16

33 34

1. Paper Tray Switch

2. Relay Sensor

3. Registration Clutch

4. Optics Cooling Fan Motor (A152 only)

5. Registration Sensor

6. Image Density Sensor

7. Power Pack-TC/SC

8. Operation Panel Board

9. Erase Lamp

10. Total Counter

11. Quenching Lamp

12. Fusing Lamp

13. Front Cover Safety Switch

14. Main Switch

15. Fusing Thermoswitch

16. Exit Sensor

17. Exhaust Blower Motor

18. Optics Thermofuse

19. Auto Image Density Sensor

20. Fusing Thermistor

21. Exposure Lamp

22. Lens Motor (A152 copier only)

23. Scanner Home Position Sensor

24. Optics Thermistor

25. Lens Home Position Sensor (A152 copier only)

26. Power Pack-CC/Grid/Bias

27. AC Drive Board

28. Fusing Triac (115 V only)

29. Scanner Motor

30. 4th/5th Mirror Home Position Sensor (A152 copier only)

31. 4th/5th Mirror Motor (A152 copier only)

32. Main Motor Capacitor

33. Main Board

34. Main Motor

35. Toner Supply Clutch

36. DC Power Supply Board

37. Relay Roller Clutch

38. Paper Feed Clutch

1-8

24 June 1994 ELECTRICAL COMPONENT DESCRIPTIONS

6. ELECTRICAL COMPONENT DESCRIPTIONS

Motors

SYMBOL NAME FUNCTION

Drives all the main unit components except for the

M1 Main Motor

M2 Scanner Motor Drives the scanners (1st and 2nd). (dc stepper) 29

M3 Lens Motor

4th/5th Mirror Motor

Optics Cooling Fan Motor

Exhaust Blower Motor

optics unit and fans. (115/220–240 Vac [ac synchronous])

Positions the lens according to the selected magnification. (dc stepper) … A152 copier only

Positions the 4th/5th mirrors according to the selected magnification. (dc stepper) … A152 copier only

Prevents built up of hot air in the optics cavity. (24 Vdc) … A152 copier only

Removes heat from around the fusing unit and moves the ozone built up around the charge section to the ozone filter. (24 Vdc)

INDEX

NO.

Magnetic Clutch

SYMBOL NAME FUNCTION

MC1

Registration Clutch

Drives the registration rollers. 3

Magnetic Spring Clutches

SYMBOL NAME FUNCTION

MSC1

MSC2

MSC3

Toner Supply Clutch

Relay Roller Clutch

Paper Feed Clutch

Drives the toner supply roller. 35

Drives the 1st and 2nd relay rollers. 37

Starts paper feed. 38

INDEX

NO.

INDEX

NO.

1-9

ELECTRICAL COMPONENT DESCRIPTIONS 24 June 1994

Switches

SYMBOL NAME FUNCTION

SW1 Main Switch Supplies power to the copier. 14 SW2

SW3

Front Cover Safety Switch

Paper Tray Switch

Cuts the ac power line, when the front cover is open.

Detects when the paper tray is set. 1

INDEX

NO.

Sensors

SYMBOL NAME FUNCTION

S4 S5 Exit Sensor Detects misfeeds. 16

S6 Relay Sensor

Scanner Home Position Sensor

Lens Home Position Sensor

4th/5th Mirror Home Position Sensor

Registration Sensor

Image Density (ID) Sensor

Auto Image Density Sensor (ADS)

Informs the CPU when the 1st scanner is at the home position.

Informs the CPU when the lens is at the home position (full size position). … A152 copier only

Informs the CPU when 4th/5th mirrors assembly is at the home position (full size position). … A152 copier only

1) Detects misfeeds.

2) Controls the relay roller clutch stop timing.

1) Detects when copy paper is set on the by-pass feed table.

2) Detects misfeeds. Detects the density of the image on the drum to

control the toner density.

Senses the background density of the original. 19

INDEX

NO.

Printed Circuit Boards

SYMBOL NAME FUNCTION

PCB1 Main Board

PCB2 AC Drive Board

PCB3

PCB4

DC Power Supply Board

Operation Panel Board

Controls all copier functions both directly and through the other PCBs.

Drives the main motor, exposure lamp, fusing lamp, and quenching lamp.

Converts the wall outlet ac power input to +5 volts, +24 volts, and a zero cross signal.

Informs the CPU of the selected modes and displays the copier status and condition on the panel.

1-10

INDEX

NO.

24 June 1994 ELECTRICAL COMPONENT DESCRIPTIONS

Lamps

SYMBOL NAME FUNCTION

L1 Exposure Lamp L2 Fusing Lamp Provides heat to the hot roller. 12 L3 Quenching Lamp

L4 Erase Lamp

Applies high intensity light to the original for exposure.

Neutralizes any charge remaining on the drum surface after cleaning.

Discharge the drum outside of the image area. Provides leading/trailing edge erase and side erase.

INDEX

NO.

Power Packs

SYMBOL NAME FUNCTION

Power Pack –CC/Grid/Bias

Power Pack –TC/SC

Provides high voltage for the charge corona, grid, and development roller.

Provides high voltage for the transfer and separation corona.

INDEX

NO.

Counter

SYMBOL NAME FUNCTION

CO1 Total Counter Keeps track of the total number of copies made. 10

Others

SYMBOL NAME FUNCTION

TH1

TH2

TR Fusing Triac

Fusing Thermistor

Optics Thermistor

Fusing Thermoswitch

Optics Thermofuse

Main Motor Capacitor

Monitors the fusing temperature. 20

Monitors the optics temperature. 24 Provides back-up overheat protection in the fusing

unit. Provides back-up overheat protection around the

exposure lamp. Start capacitor. 32 Switches the fusing lamp on and off. (115 V only)

Note: In the 220V-230V/240V version, the triac

is built-in the ac drive board

INDEX

NO.

INDEX

NO.

1-11

G2: Relay Gear G8: Relay Gear

BP4

DRIVE LAYOUT 24 June 1994

7. DRIVE LAYOUT

G14

G13

G15 G16

G17

G18 G19

G1: Main Motor Gear

BP6 BP5

G22 BP1G21G20

G26 G25

TB2

TB3

TB1

BP2

G12 G11

G10

G23

G2G1

G9 G8

G7 G6

G4 G3

BP3 G24

G9 G8

G23: Timing Belt Drive Gear

BP1: Timing Belt Pulley

TB1: Timing Belt

G10 Relay gear

G11: Timing Belt Drive Gear

BP5: Timing Belt Pulley

TB3: Timing Belt

Development Section

BP6: Timing Belt Pulley

G12: Development Gear

Development Unit

G13: Relay Gear

G14: Toner Supply CL Gear

Toner Supply CL

Toner Supply Unit

G9: Relay Gear

Cleaning Unit

G3: Fusing Drive Gear

Fusing and Exit Unit

G4: Hot Roller Gear

G7: Relay Gear

G6: Relay Gear

G5: Exit Roller Gear

1-12

24 June 1994 DRIVE LAYOUT

G15: Registration CL Gear

Registration CL

Registration Rollers

G20: Relay Gear

G17: Relay Roller CL Gear

Relay Roller CL

G16: 2nd Relay Roller Gear

2nd Relay Rollers

Paper Feed Section

BP2: Timing Belt Pulley

G22: Relay Gear

Paper Feed Section

G21: Paper Feed CL Gear

Paper Feed CL

Feed Rollers

G24: Timing Belt Drive Gear

BP3: Timing Belt Pulley

TB2: Timing Belt

BP4: Timing Belt Pulley

G25: Relay Gear

G26: Drum Drive Gear

G18: Relay Gear

G19: 1st Relay Roller Gear

1st Relay Rollers

1-13

POWER DISTRIBUTION 24 June 1994

8. POWER DISTRIBUTION

AC Power (115V or 220V – 240V)

Fusing Lamp

Exposure Lamp

Main Motor

Quenching Lamp

Document Feeder (Option)

AC power DC power

Main SW

Cover Safety SW

Power Relay

(RA401)

Fusing Lamp Drive Circuit

Exposure Lamp Drive Circuit

Main Motor

Relay (RA402)

AC Drive Board

DC Power Supply Board

24V (VA)

24V (VA) 5V (VC) Zero Cross

RAM Pack

Main

Board

Anti-condensation Heaters

-Drum (Option)

-Optics (Option)

Scan Signal

5V (VC)

24V (VA)

5V (VC)

24V (VA)

Operation Panel Board

Sensors

Switches DF Interface Board (A152 copier only)

Thermistors

Solenoids

Clutches

Power Packs

Lens Motor

(A152 copier only)

4th/5th Mirror Motor

(A152 copier only)

Optics Cooling Fan

Motor (A152 copier only)

Exhaust Blower

Motor

Image Density Sensor

Scanner Motor

When this copier is plugged in and the main switch is turned off, ac power is supplied via the ac drive board to the optio na l ant i-con de nsa tio n heat ers. When the front cover and/or the exit cove r is open , th e cove r sa fe ty switch completely cuts off power to all ac and dc compo nent s. The RAM pack has a back up power supply (dc battery) for th e service prog ram mode data and misfeed job recovery.

When the main switch is turned on, the ac power sup ply to the anti-condensation heat er is cut of f an d ac power is supp lied to the ac drive board. The dc power supply board receive s wa ll out let ac powe r through the ac drive board.

The dc power supply board converts th e wall outle t ac po wer inp ut to +5 volts, +24 volts, and a zero cross signa l, all of wh ich are supp lied to th e main board.

1-14

24 June 1994 POWER DISTRIBUTION

The main board supplies dc powe r to all cop ier dc comp on ents. All sensors, switches, thermistors, and the DF interf ace board (op tio n) op era te on +5 volts. The operatio n pane l o per at es on +5 vo lts sup plied by the main board.

All other dc components includin g the power relay (RA401) and the main motor relay (RA402) operat e on +24 volt s.

When the main board receives power, it act ivat es th e power rela y (RA401) which then supplies ac power to the fusin g lamp drive circuit, and the exposure lamp drive circuit on the ac drive board. The fusing lamp drive circuit receives a trigger signal from th e main boa rd and the fusing lamp lights. The exposure lamp do es no t tu rn on unt il t he ma in bo ard send s a trigger pulse to the exposure lamp drive circu it.

When the Start key is pressed, the main bo ard ene rgize s the main mot o r relay (RA402). Then, the ma in mot or an d the quenching lamp turn on. When the main switch is turned off, power is cut off to the main board an d to RA401, and the optional drum and optics anti-condensation heaters are turned on.

1-15

SECTION 2

DETAILED SECTION

DESCRIPTIONS

24 June 1994 DRUM

1. DRUM

1.1 DRUM CHARACTERISTICS

An organic photoconductor (OPC) dru m is used in this mo del. The OPC drum has the characteristics of :

1. Being able to accept a high negative electrical charge in the dark. (Th e electrical resistance of a photocon ductor is high in the absence of light.)

2. Dissipating the electrical charge when exposed to light. (Exposure to light greatly increases the conduct ivity of a photo con du cto r.)

3. Dissipating an amount of charge in dire ct pro po rtio n to the inte nsity of the light. That is, where strong er ligh t is directed to the photoconductor surface, a smaller voltage remains on the drum.

4. Being less sensitive to changes in tempe rature (when compared to selenium F type drums).

5. During the drum’s life, drum residu al voltage gradually increases and the photoconductive surface becomes worn. Therefore, some compen sat ion for these characteristics is required.

2-1

DRUM 24 June 1994

1.2 DRUM UNIT

[E]

[A]

[G]

[F]

[C]

[D]

[B]

[C]

[D]

The drum unit [A] consists of an OPC drum [B], ID sensor board [C] and a pick-off pawl [D]. When the drum, the pick-off pawl, or th e ID sensor is replaced or cleaned, the drum unit must be removed from the copier. Therefore, the drum has a coupling device wh ich is connected to the drum drive gear [E]. The ID sensor conne cto r [ F] is used for th e ID sen sor.

The main motor provides rotat ion direct ly to th e drum thro ug h a series of gears.

The pick-off pawl [D] is always in cont act with the drum surface.

2-2

24 June 1994 DRUM CHARGE

2. DRUM CHARGE

2.1 OVERVIEW

[A]

[B]

[D]

[A]

This copier uses a double wire scorotro n and a highly sensitive OPC drum [A]. The corona wires [B] ge ne rat e a corona of negative ions when the CC/Grid/Bias power pack [C] applies a high voltage. The CC/Grid/Bias power pack also applies a negative high volta ge to a stainless steel grid plate [D]. This insures that the drum coating receives a uniform negative charg e as it rotates past the corona unit.

[C]

[D]

The exhaust fan, located abo ve the cop y exit, causes a flow of air from the upper area of the development unit through the ch arg e coro na unit . This prevents an uneven bu ild-u p of negative ions that can cause uneven image density. The exhaust fan runs at half spe ed when in the st and-by condition and at full speed while copying.

The exhaust fan has an ozo ne filte r (a ctive ca rbo n) which adsorbs ozone (O3) generated by the cha rge corona. The ozone filte r decre ases in efficiency over time as it adsorbs ozone. The ozone filter should be replaced at every 80K copies.

The flow of air around the charge corona wires may deposit paper dust or toner particles on the corona wire . The se pa rticle s may interfere with charging and cause low density ba nds on cop ies. The wire cleaner cleans the corona wire when the op era tor slides the corona unit out and in.

2-3

DRUM CHARGE 24 June 1994

2.2 CHARGE CORONA WIRE CLEANER MECHANISM

[B]

[A]

[D]

[C]

Pads [A] above and below th e charge corona wires clean the wires as th e charge unit is manually slid in and out.

The cleaner pad bracket [B ] rotates when the charge unit is fully e xte nd ed and the bracket is pulled up against the rear en dblock [C]. This moves the pads against the corona wires (see illu stra tio n). If the charge unit is not fully extended, the pads do not tou ch th e corona wires.

The pads move away from the wires when the charg e unit is fu lly inse rte d and the cleaning bracket is pushed against the front endblock [D].

After copier installa tio n the key operator should be instru cte d to use this mechanism when copies have whit e stre aks.

2-4

Power Pack CC/Grid/Bias (P1)

Charge Corona

Development Bias

24 June 1994 DRUM CHARGE

2.3 CHARGE CORONA CIRCUIT

CN1-1 CN1-2 CN1-3

CN1-5

CN1-7

PWM Duty cycle

=t2/t1 x 100 (%)

Grid

CC Trig [

Grid Trig (PWM) [

Main Board (PCB 1)

▲0→0/5]

GND [0]

VA [24]

VC [5]

▼24]

CN119-7 CN119-6 CN119-5

CN119-3

CN119-1

The main board supplies +24 volt s to th e CC/G rid/Bias power pack at CN1-1 as the power supply source. Afte r t he Sta rt key is pressed the CPU drops CN1-3 from +24 volts to 0 volts. This energizes the charge coron a circuit within the CC/Grid/Bias power pack, which applies a high nega tive volta ge of approximately –7.0 K volts to th e cha rge corona wires. The corona wires then generate a negative corona charge.

The grid plate limits the cha rge voltage to ensure that the charge does not fluctuate and that an even charge is applied to the drum surfa ce.

The grid trigger pulse applied to CN1-5 is a pulse width modulated signal (PWM signal). This signal is not only a trigger signal, it also chan ges the voltage level of the grid. As the width of the pulse ap plie d incre ases, the voltage of the grid also incre ases.

2-5

DRUM CHARGE 24 June 1994

2.4 GRID VOLTAGE CORRECTI ON

To maintain good copy quality ove r the drum’s life , th e grid volta ge is changed by the following:

• Drum residual voltage correction (Vr correction)

• Drum wear correction

2.4.1 Drum Residual Voltage Correction (Vr correction)

During the drum’s life, the dru m may fat igue electrically and residual voltag e (Vr) on the drum may gradually in crea se. Wh en this ha ppen s, th e corona charged voltage on th e dru m is not discharged enough in the quenching and exposure processes. Even if the development bias is applied in the development pro cess, the backg round area of the original on th e drum may attract some toner. This may cause dirty background on copies. The Vr correction prevents this ph enomenon as follows:

A pattern (Vr pattern) is develope d on the drum eve ry 1,0 00 copie s and its reflectivity is detected by the ID sensor to measu re th e residua l volta ge . This is called residual voltage detect ion . (If the reflectivity is low, the residual voltage will be high.) When the Vr pattern is developed, all blocks of the erase lamp turn on, and th e de velo pment bias voltage is 0 volt.

The CPU determines what level of Vr co rrect ion is necessa ry dep en din g on the output (Vr ratio [L]) from the ID sensor.

Vrp

L =

x 100 (%)

Vsg

Vrp: ID sensor outp ut for Vr pattern

Vsg: ID sensor output for bare drum The current Vr ratio is disp laye d by SP67. The CPU increases the development bias voltage depending on the Vr ratio

to prevent dirty backgrou nd on copies, (See page 2-30 for more informatio n. ) The CPU also increases the grid volta ge to ensure prop er imag e de nsit y depending on the Vr ratio. (See page 2-8.)

2-6

24 June 1994 DRUM CHARGE

2.4.2 Drum Wear Correction

During the drum’s life, the photoco nd uct ive surf ace of the drum becomes worn by contact with the cle an ing blad e an d de veloper on the development roller. This effects ability of th e dru m t o hold a cha rge . This cha racteristic especially affects develo ping of the ID sensor patte rn. Th e ID sen sor pa ttern developed on the dru m becomes lighter causing highe r ton er concentration in the developer. The drum we ar corre ctio n is made to pre ven t th is phenomenon and is as follows:

The CPU keeps track of the drum motor rota tion time that corresponds to the wear of the photoconductive layer. The grid voltage for the toner density detection increases at set int erval. The grid voltage for the residual voltage (Vr) detection also increase s at th e same interval. (See page 2-9.) The drum motor rotation time is displayed by SP57.

2.5 GRID VOLTAGE FOR IMAGE DENSITY CONTROL

The main board controls the grid volt age fo r the copy imag e through the CC/Grid/Bias power pack. As the grid voltage for the imag e densit y control becomes less, the copy image become s light er an d vice versa .

The grid voltage is based on the standard grid voltage and correction factors as follows:

Grid Voltage = Standard image density grid volt age (–6 80 volts [SP60 = 4])

Vr correction factor

Auto image density level facto r (S P34)

2.5.1 Standard Image Density Grid Voltage

The standard image density grid voltage (SP60) is set at the factory and the setting is differen t for each machine. The setting of SP60 is described on the SP mode data sheet located inside the inner cover of the machine.

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DRUM CHARGE 24 June 1994

2.5.2 Drum Residual Voltage (Vr) Correction Factor

Vr ratio (L) (%) (SP67) Change of grid voltage (volts)

100 to 84

83 to 58 –40 57 to 41 –80 40 to 28 –120

27 to 0 –160

±0

L = Vrp/Vsg x 100 (%)

Vrp: ID sensor output for Vr pattern Vsg: ID sensor output for bare drum

During the drum’s life, drum residual volt age (Vr) may gradually increase. Vr correction compensate s fo r the resid ua l voltage on the drum. The Vr correction is done every 1000 copies. The CP U increa ses the development bias voltage and the grid volta ge . The above table shows how the grid voltage changes depending on the Vr ratio.

2.5.3 Auto Image Density Level Factor (SP34)

Auto image density level Data (SP34) Change of grid voltage (volts)

Normal 0 *

Darker 1 –40

Lighter 2

±0

* Factory setting

The grid voltage and the expo sure la mp volt ag e are co nst an t reg ardless of the output from the auto image de nsit y sensor. Only the development bia s voltage varies depending on the output from the auto image density sen sor.

But only when the auto image density level data in SP34 is set to darker, the grid voltage is changed –40 volts as shown in the above ta ble . Whe n it is set to lighter, the grid vo lta ge doe s not chan ge . Howe ver, the development bias voltage is corrected.

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24 June 1994 DRUM CHARGE

2.6 GRID VOLTAGE FOR TONER DE NSITY DETECTION AND

RESIDUAL VOLTAGE (Vr) DETECTION

The guid voltage is the same fo r both toner density detectio n an d resid ua l voltage correction.

Grid voltage = Standard ID sensor grid voltage (–460 volt s [SP 62 =4] )

Drum wear correction factor (SP57)

Drum Wear Correction Factor (SP57)

Main motor rotation time (SP57) Change of grid voltage (volts)

0 to 2H

2 to 65H –20

65 to 112H –40

112 to 157H –60

More than 157H –80

±0

The grid voltage for toner density detection is the same as it is for th e residual voltage (Vr) detection. However, the developme nt bias volt ag e is different. (See page 2-30 and 2-35.)

2-9

[E]

OPTICS 24 June 1994

3. OPTICS

3.1 OVERVIEW

[B]

[C]

[D]

During the copy cycle, an image of the original is reflecte d onto the drum surface through the optics assembly as follows.

Light Path:

Exposure Lamp [A] → Original → First Mirror [B] → Second Mirror [C] → Third Mirror [D] → Lens [E] → Fourth Mirror [F]→ Fifth Mirror [G] → Sixth Mirror [H] → Drum [I]

[A]

[H] [F] [J]

[I]

[G]

This copier has six standard reprod uct ion ratios (A152 copier only), three reduction ratios, two enlarg eme nt ra tio s, an d full size. It also has a zoom function. The opera tor can change the reprod uct ion ratio in one percent steps from 61% to 141%.

Stepper motors are used to cha nge th e positio ns of the lens and mirrors (A152 copier only). Separate mot ors are used beca use the wide ran ge of reproduction ratios make s it mechanically difficult for one motor to posit ion both the lens and mirrors. A ste pp er motor is also used to drive the scanner. This motor changes the scanner spe ed accord ing to th e rep rod uction ratio.

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24 June 1994 OPTICS

The CPU monitors the temperature aro un d the optics cavit y thro ugh a thermistor which is located at the up per le ft rear side of the copier frame. When the temperature reaches 45°C, the optics cooling fan [J] (A15 2 cop ier only) starts rotating to draw cool air into the optics cavit y. However, A151 copier is not equipped with a cooling fan. The machine will stop if the optics cavity overheats. (Se e pa ge 6-52.) In this case, the Energy S ave r in dica tor blinks and the Start key turns red.

The air flows from the right to the left , and exh au sts th rou gh the vent s in the left side of the upper cover. This fan operates until t he te mp erature drops below 45°C.

The thermofuse pro vides back-up overheat prot ect ion. It opens at 128°C and removes ac power to the exp osure lamp.

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Ricoh FT 3013 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual