Ricoh NC305 Service Manual

RICOH NC305

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 some compo ne nt s of th e copier and the paper tray unit are supplied with electrical voltage even if the main switch is turned off.

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

5. The inside and the met al parts of the fusing unit become extre mely ho t while the copier is operat ing . Be ca ref ul to avoid touching those components with your bare hands.

HEALTH SAFETY CONDITIONS

1. Never operate the copier without the ozone filters installed.

2. Always replace the ozone filters with the specified ones at the specifie d intervals.

3. Toner and developer are non-toxic, but if you get either 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.

2. The RAM board on the main control board has a lithium battery which can explode if replaced incorre ctly. Re pla ce th e ba tt ery on ly with an iden tica l one. The manufacturer reco mmen ds replacing the entire RAM board. Do not recharge or burn this battery. Used batteries must be handled in accordance with local regula tio ns.

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 lithiu m bat te ries in ord er to dispo se of them later, do not put more than 100 batteries per seale d box. Storing larger numbers or not sealing them apart may lead to che mical rea ctions and heat build-up.

RICOH NC305

SECTION 1

OVERALL INFORMATION

20 December 1991 SPECIFICATIONS

1. SPECIFICATIONS

Configuration: Desktop Copy Process: Electrostatic transfer system Originals: Book/sheet, fixed plate n Original Alignment: Left side centered against side scale Maximum Original Size: A3, 11" x 17" Copy Paper Size: Maximum: A3, 11" x 17"

Minimum: A6R, 81/2" x 51/2 " lengthwise

Copy Paper Weight: Black or single color copies: 52 to 104 g

14 to 28 lb

Full color copies: 64 to 104 g

17 to 28 lb

Copying Speed:

A4 sideways,

1/2" x 11"

8 sideways, or

smaller sizes. Black 30 cpm 12 cpm Single Color

(1C and 2C) Full Color (3C) 5 cpm 4 cpm Full Color (6C) 2.5 cpm 2 cpm

7.5 cpm 6 cpm

A4 lengthwise,

1/2" x 11"

8 lengthwise, or larger sizes.

First Copy (A4, 81/2" x 11" sideways):

Warm-up Time:

Black: 6 seconds (9.0 s for ID

sensor check cycle) Single Color (Y, M, C): 12 seconds Single Color (B, G, R): 16 seconds Full Color: 20 seconds Photo Mode: 32 seconds

Within 3.5 minutes (Room temperature 20 °C)

1-1

SPECIFICATIONS 20 December 1991

Automatic Reset: After 60 seconds (Adju sta ble from 0 to 180

minutes by SP mode) – Black/Color Copy: Black mode – Copy Counter : 1 – Reproduction Ratio: Full size – Interrupt Mode: OFF – Sort/Stack OFF – Image Density Auto ID – Program Mode OFF – All application modes: OFF

Photoconductor: Organic photoconductor drum, 120 mm in

diameter

Drum Charge: Double-wire with grid wires (Neg at ive Cha rge ) Erase Lamp: 128 LEDs (2.5 mm) Fixed Reproduction Ratio s:4 enlargeme nt ratios and 5 reduction ratios, plus

4 programmable ratios betwe en 50% and 200%

Zoom Range: Zoom from 50% to 200% in 1% increments

(Partial enlargemen t for ra tio s abo ve 142%.)

Scanning System: One directional scanning with mirrors an d len s Scanner Light Source: Seven halogen bulbs in series (320 W/ 80 V) Exposure System: Slit expo sure , moving optics Lens: Through lens, f = 215 mm, F = 4.6 Development: Dual-component dry toner system (Black: 1.0 kg,

color: 0.7 kg)

Toner Replenishment: Black: 390 gram cartridge

Color: 100 gram cartridge

Toner Consumption: (A4 or 81/2" x 11",

Black: 6,800 copies/cartridge Color: 1,800 copies/cartridge

7% Originals) Development Bias: Negative variable bias Toner Density Control: Primary: Toner density sensor in dev. unit

Secondary: Pattern density detection by

photosenso r

Image Transfer: Single wire DC corona (variable nega tive charg e

through transfer drum sheet)

1-2

20 December 1991 SPECIFICATIONS

Paper Separation: Clamp mechanism, single wire AC corona, and

pick-off pawls

OPC Drum Cleaning: Magnetic brush (250 grams of clea nin g carrier)

with bias roller and pre-cleaning corona (single wire AC corona)

Quenching: Photo quenching by LEDs Paper Feeding: Double universal cassett es (25 0 she et capacity) Paper Feed System: Feed and reverse roller (FRR) system Image Fusing: Heat and pressure type, silicone rubber rollers

and silicone oil

Fusing Lamp: Two halogen lamps, 650 W and 550 W/115 V,or

230 V

Copy Tray Capacity: 100 sheets for A3 (11" x 17")

250 sheets for all other p ape r sizes

Self-diagnostic Codes: 38 codes, indicated in the copy counter Power Source: 115 V 60 Hz 12 A

110 V 60 Hz 13 A 220/230/240 V 50 Hz 7 A

Power Consumption: Maximum: 1.4 kW (110/115 V)

1.5 kW (220/230/240 V) Warm-up: 0.9 kW (average) Ready: 0.15 kW (fusing lamp off)

0.22 kW (fusing lamp on) Copy cycle: 1.0 kW (average)

Dimensions (W x D x H): Machine body: 835 x 700 x 507 millimeters

32.87 x 27.56 x 19.9 6 inch es

Weight: Approximately 136 kg (299.8 lb) Optional Equipment: — ARDF (automatic reverse document feeder)

— 20 bin sorter — 3rd paper feed table — Editor — Large capacity tray — Multi by-pass tray — Key counter (locally procured )

1-3

BASIC CONCEPTS OF COLOR COPYING 20 December 1991

2. BASIC CONCEPTS OF COLOR COPYING

2.1 COLOR REPRODUCTION P ROCE SS

2.1.1 Light and Color

1) White Light When sunlight passes thro ugh a prism, it separates into various colors. This is because sunlight is compo sed of light of different wavelengths. It is called "white light" since sunlig ht is sensed as "white" by the eyes.

2) Wavelength and Color The eye senses a different color when light with a differe nt wavelength reaches the eye.

• Light with a 580 nm

wavelength is recognized as "Yellow".

• Light with a 610 nm

wavelength is recognized as "Orange".

Ultraviolet

light

Violet Blue Green Yellow Orange Red

Blue (B)

400

Green (G)

500 600 700

Red (R)

Infrared

light

When light rays with wavelengths bet ween 400 and

100

500 nm reach the eye, violet-blue (in this manual, it is called "Blue") is recognized.

Also, "Green" is recognized fo r

80 60 40 20

light with wavelengths between 500 and 600 nm, and "Red" is

400

500

600

700 nm

recognized for light with wavelengths from 600 to 700 nm.

The sensitivity range for the eye is 400 to 700 nm, and the peak sensitivity is at 556 nm.

Infrared rays have a wavelen gth of more than 700 nm and ultra viole t rays have a wavelength of less th an 400 nm. Neit he r are visible to the eye.

1-4

20 December 1991 BASIC CONCEPTS OF COLOR COPYING

3) Color of objects When an object is exposed by th e white light, it absorbs some rays and reflects other rays.

a. When light rays around 610 nm

are reflected, and other ra ys are

Blue

Green

Red

absorbed, this object is said to be "Orange".

(B)

(G)

(R)

b. When all light rays are reflecte d,

the object is recognized as

400 500 600

"White".

c. When all rays are absorbed, the

object is recognized as "Black" .

When a white object is seen through a red filter, it is seen to be "red". Although it reflects all light rays, only red can pass through a red filter.

4) The three basic colors The eye contains thre e kind s of colo r sensitive cells. These cells are called B cones, G cones, and R cones an d they are sensitive to "blue", "green", and "red" light. The pe rception of color depends on th e rela tive level of excitation of these cells. Blue, green and red are called the "Three Basic Colors".

2.1.2 Light Mixture

1) Blue + Green

Blue

Green

When both "Blue" and "Gree n" light reach the eyes, the eyes sense a clear light blue, which is called "Cyan". Since white ligh t

(B)

400 500 600 700nm

(G)

is composed of "Blue" , "Green", and "Red" light, "Cyan" means that the red component has been eliminated from white light. "Cyan" and "Red" are called "Complimentary Colors".

Blue (B)

Green (G)

Cyan (C)

700nm

1-5

BASIC CONCEPTS OF COLOR COPYING 20 December 1991

2) Green + Red When both "Green" and "Red"

Green

Red

light reach the eyes, they sense "Yellow". Since "Yellow" means that "Blue" is eliminated from white light, "Yello w" an d "B lue " are called "Complimentary

400 500 600 700nm

(G)

(R)

Colors".

Green (G)

Red (R)

Yellow (Y)

1-6

20 December 1991 BASIC CONCEPTS OF COLOR COPYING

3) Blue + Red When both "Blue" and "Red" light

Blue

Red

reach the eyes, they sense purple-red color, which is called "Magenta". "Magenta" and "Green" are "Complimentary

(B)

400 500 600 700nm

(R)

Colors".

4) Summary

Light

White

Black

Toner

2.1.3 Color Toner

1) Light Reflective Characteristics a. Cyan Toner

"Cyan" toner absorbs "Red" ra ys and reflects "Blue" and "Green" rays. Reflected "B" and "G" rays are seen as "Cyan".

Blue

Green

Blue (B)

Red (R)

Light

Toner

Complimentary Colors

White

Magenta (M)

(B)

400 500 600 700nm

(G)

White paper

b. Magenta Toner

"Magenta" toner abso rbs "G reen" rays and reflects "Blue" and "Red" rays. Reflected "B" and "R" rays are seen as "Mag en ta ".

Blue

(B)

400 500 600 700nm

Red

(R)

1-7

White paper

Toner

BASIC CONCEPTS OF COLOR COPYING 20 December 1991

c. Yellow Toner

"Yellow" toner absorbs "Blue" rays and reflects "Green" and "Red" rays. Reflected "green" and "red " ligh t rays are seen as "Yellow".

Red

(R)

400 500 600 700nm

Green

(G)

2) Color Toner Mixtures

a. Cyan + Magenta When cyan and magenta ton e r ar e combined on white paper, the magenta layer absorbs green and the cyan layer absorbs red. As a result, blue is reflected.

b. Magenta + Yellow When magenta and yello w ton er are combined on white paper, the magenta layer absorbs green, and the yellow layer absorbs blue. As a result, red is reflected.

Toner

White paper

Black

M Toner

Toner

Y Toner

Toner

c. Cyan + Yellow When "Cyan" and "Yellow" to ne r a re combined on white paper the "C" laye r absorbs "Red", and the "Y" layer absorbs "Blue". As a result, "Gre en" is reflected.

d. Cyan + Magenta + Yellow When all three color toners are combined, the cyan layer absorbs red , th e magenta layer absorbs green, and the yellow layer absorbs blue. As a result, no visible lig ht is reflected, and we see black.

1-8

White paper

Toner

Black

Y Toner

M Toner

Toner

20 December 1991 BASIC CONCEPTS OF COLOR COPYING

2.1.4 The Characteristics of Filters

1) Red Filter The "Red" filter allows "Re d" lig ht to pa ss through and absorbs "Blue" and "Green".

Red

(R)

400 500 600 700nm

2) Green Filter The "Green" filter allows "G reen" light to pass through and ab sorbs "Blue" and "Red".

Green

(G)

400 500 600 700nm

R Filter

G Filter

3) Blue Filter The "Blue" filter allows "Blu e" light to pass through and absorbs "Green" and "Red" rays.

Blue

(B)

400 500 600 700nm

1-9

B Filter

BASIC CONCEPTS OF COLOR COPYING 20 December 1991

2.1.5 Full Color Copy Process

Three filters (red, green, blue) and three color toners (cyan, magenta, yellow) are used to make full color copies as follows.

1) 1st Cycle: Cyan Development wit h "Re d" filte r expo sure

Original

Red Filter

OPC Drum

Cyan Development

White

BGR BGRBRG

BGRYCM

Toner

OPC Drum

Black

C C

Paper

Image

Transfer

2) 2nd Cycle: Magenta Develop men t with "Gre en " filter exposure

Original

Green Filter

OPC Drum

Magenta Development

White Black

BGRYCM

BGR BGRBRG

BGR

M MM

Toner

OPC Drum

Image

Transfer

C C

M M

C C

Paper

3) 3rd Cycle: Yellow Development with "Blue" filter exposure

Original

Blue Filter

OPC Drum

Yellow Development

White Black

BGRYCM

BGR

OPC Drum

Toner

BGRBRG

1-10

Image

Transfer

White

BGRYCM

Y C M CCC

Paper

Image Fusing

Paper

Y M

Black

20 December 1991 COPY PROCESS AROUND THE DRUM

3. COPY PROCESS AROUND THE DRUM

1) OPC Drum A unique OPC drum (120 mm diameter) ha s high resistance in the dark and low resistance under light.

The drum speed is 226 mm/sec. in black development mode and 113 mm/sec. in color development mode.

2) Drum Charge In the dark, the charge corona unit applies a negative charge to the drum. The grid plate ensures tha t the charge is applied uniformly. The charge remains on the drum surfa ce be cause the photoconduct ive drum has high electrical resistance in the dark.

1-11

COPY PROCESS AROUND THE DRUM 20 December 1991

3) Exposure An image of the original is reflected to the OPC drum via mirrors, a len s, and a light separation filter. The charge on the drum surface is dissipated in direct proportion to the intensity of the light exposing the OPC drum, thus producing an electrical lat ent image.

The neutral density filter is used in bla ck and sin gle color cop y mo des. The color filters are used in fu ll co lor cop y mode and single color erase mode.

In full color mode, the original is scanned three times with a diffe ren t filt er being used each time (red filt er fo r cya n development, green filter for magenta developme nt, blue filter for yellow develo pme nt).

4) Erase The erase lamp (red LED with 2.5 mm steps) illuminates the areas of the charged drum surface that will not be used fo r the copy imag e. The resistance of the drum in the illuminated areas drops and the charge dissipates.

5) Development Each time a scan is made, the development roller moves negatively charged black, cyan, magenta, or yellow developer to the OPC drum. The toner is attracted to the nega tive ly charged areas on the drum surface, thus developing the latent image. The other colo r developers remain inside the development unit.

6) Toner Density Detection The toner density sensor on the bot to m of ea ch de velo pment unit detects the magnetic permeability of deve loper each time a scan is made. If the voltage output by the toner den sity sen sor is lower th an the st anda rd output voltage, additio nal t oner is su pplied. (The standard output volta ge is stored in memory when develope r is replace d, and it is updated by ID sensor data.) The tone r density sensor also detects when toner is about to run out.

7) Pre-transfer Lamp (PTL) The pre-transfer lamp LEDs illuminat e the OPC drum to lower the dru m potential for image transfer and OPC drum cleanin g.

1-12

20 December 1991 COPY PROCESS AROUND THE DRUM

8) Image Transfer Copy paper is fed to the transfer drum and th e leading edge is clamped.

A negative charge is applie d to the backsid e of paper through the tran sfe r drum sheet. This charge pulls the tone r particles on the OPC drum surface onto the copy paper.

When the transfer corona current is applie d, the copy pa per is electrica lly attracted to the transfer dru m sheet. In full color mode, the copy paper makes three passes thro ug h the image transfer area. Since the tran sfer drum sheet has already been charge d during the first transfer cycle, the second transfer charge must be high er th an the first cha rge for image transfer to take place. The same is true for the third transfer cycle.

To increase copy speed whe n cop y p aper of A4/11" x 81/2" ( LT sideways) sideways or smaller sizes is fed, the transfe r drum turns in high speed while a later half of the transfer drum shee t is passing through image transfer section.

9) Drum Image Control a. ID Sensor

The sensor pattern is made by charging a strip of the drum and then erasing all but a small section of th e charged area. This section is developed with a higher develop ment bias than normal. (There is no sensor pattern in th e optics.) The ID sensor (photosenso r) d et ect s t he reflectivity of the pattern and the erased drum surface and outputs two voltages. The ratio of the one output voltage to the other changes whenever the toner de nsit y of the sensor pattern change s. The ton er supply level voltage of the toner de nsit y sensor is then shifted to increase or decrease the toner concentration in the deve loper and maintain the correct amount of each color of toner on the OPC drum. This keeps the colors in balance.

b. VL Sensor

To prevent dirty background on copies due to drum residual charge and exposure decay of th e dru m surface, the exposure lamp voltag e is shifted up based on the comparison of VL sensor data with initial set data. The VL pattern is located in th e op tics, and it is developed during the copier warm-up cycle if the main switch is turned on and the fusing temperature is lower than 50°C.

10) Pre-cleaning Corona The pre-cleaning corona (PCC) a pplies an AC corona with a positive DC bias to the drum. This reduces the ele ctrica l a tt ract ion of to ne r to th e drum so that it will be easier to clea n th e drum.

1-13

COPY PROCESS AROUND THE DRUM 20 December 1991

11) Drum Cleaning Negatively charged cleaning carrier attracts positively charged toner from the drum surface.

The cleaning bias roller has a negat ive bia s t hat ele ctrically separates toner from the cleaning carrier. The bia s blade then peels toner off the roller, and the cleaning coil carries toner to the collectio n bott le.

12) Quenching After toner is removed from the OPC drum surface, the qu en chin g lamp (LEDs) turns on to electrically neutralize the drum .

13) Paper Separation The clamper opens and pushes the paper u p. The pick-o ff pawls then peel the paper off th e tra nsfer drum. An AC separation coron a breaks the electrical attraction betwe en the copy pa per and the drum so that the paper separates easily from the drum.

14) DC Discharge The inner DC discharge corona applies a positive potent ial to the negatively charged inner surf ace of th e transfer drum sheet. The outer DC discharge corona applies a nega tive potential to the oute r surface of the transfer drum sheet. This discharges the transfer drum sheet.

15) AC Discharge An AC discharge with differe nt frequency is applied to both the inner and outer sides of the transf er dru m shee t. This n eutralizes the transfer drum sheet.

16) Transfer Drum Cleaning After the copy cycle, th e clea ning brush contacts the tra nsfer drum sheet and removes toner on the transfe r drum. The transfer drum may become dirty if there is a paper jam or if a large original is copied onto a small sheet of copy paper. This is to avo id to ne r st ain s on th e reverse side of the next copy.

1-14

20 December 1991 PAPER PATH

4. PAPER PATH

(5)

(4)

(6)

(3)

(1)

1) Paper Feed This copier uses the feed and reverse roller (FRR) system. The FRR mechanism takes a sheet off the pap er sta ck a nd feeds it to the registration rollers.

The standard version of th is copier has two paper feed station s. An additional paper feed station is available when the copier is installed with the optional table . The optional multi by-pass tray can be used only in the fist paper fe ed station. The copy paper capacity is as follows: Cassette: 250 she ets Large capacity tray: 1000 sheets

Multi by-pass tray: 50 sheets

(2)

1-15

PAPER PATH 20 December 1991

2 ) Registration

When the copy paper reaches the registratio n rolle rs (not turning at this time), it buckles slightly to correct skew an d sea t be twe en the ro llers.

The registration rollers start turn ing to feed paper to the paper clamp. The rollers turn quicker than normal at this time so that the paper buckles slightly when the leading edge con ta cts the clamp. This ensures that there will be no skewing when the paper is clamped.

3) Image Transfer and Paper Separation See the Drum Processes section.

4) Paper Transport/Image Fusing After paper separation , th e pa per is tra nsp ort ed to th e fu sing ro llers by the transport belt. The tra nsp ort vacuum fan pulls the paper onto the belt to ensure smooth transport.

The paper passes betwee n the fusing rollers, which bond the ton er to the paper with heat and pressure. In both OHP mode an d glo ss copy mode (only for copy paper in A4/1 1" x 81/2" (LT sideways) or smaller sizes), turning spe ed of th e fu sing rollers is lowered to supply more heat to the paper.

5) Copy Tray/Sorter The copy is fed out to the copy tray by the exit rollers or to the to p bin of the 20 bin sorter.

The sort and stack functions of the sorter can only be used wit h black/white copies.

6) Auto Reverse Document Feeder The optional document fe eder ha s thre e mod es: ADF, SADF, ARDF.

The bottom sheet is separate d fro m t he origin al stack by the separation belt and is fed to the exposure glass.

1-16

20 December 1991 MECHANICAL COMPONENT LAYOUT

5. MECHANICAL COMPONENT LAYOUT

26 27

30 31

1-17

MECHANICAL COMPONENT LAYOUT 20 December 1991

1. 3rd Mirror

2. 2nd Mirror

3. 1st Mirror

4. ARDF

5. Separation Corona Unit

6. Transfer Drum

7. Lens

8. Cleaning Bias Roller

9. PCC

10. Cleaning Roller

11. Charge Corona Unit

12. Color Filters

13. 4th Mirror

23. Cyan Development Rolle r

24. Pre-transfer Lamp (PTL)

25. Cyan Toner Density Sensor

26. Transfer Corona Unit

27. Transfer Drum Cleaning Unit

28. Registration Roller

29. Inner Discharge DC Corona

30. Inner Discharge AC Corona

31. Outer Discharge DC Corona

32. Outer Discharge AC Corona

33. Relay Roller

34. Reverse Roller

35. Paper Feed Roller

14. Optics Cooling Fan

15. Erase Lamp

16. Black Development Roller

17. Black Toner Supply Unit

18. Black Toner Density Sensor

19. Yellow Development Roller

20. Yellow Toner Density Sensor

21. Magenta Develop ment Roller

22. Magenta Toner Density Sensor

36. Pick-up Roller

37. Table with 3rd Paper Feed Unit

38. Pressure Roller

39. Hot Roller

40. Exit Roller

41. Sorter

42. Large Capacity Tray

1-18

20 December 1991 ELECTRICAL COMPONENT DESCRIPTIONS

6. ELECTRICAL COMPONENT DESCRIPTIONS

SYMBOL NAME FUNCTION LOCATION

MOTORS

M1 Scanner Motor Drives the scanner. (servomotor) 56 M2 2nd Scanner Position

Motor

M3 Lens Motor Positions the lens based on the

M5 Filter Motor Rotates the filter assembly to position the

M6 Optics Cooling Fan Cools the optics cavity. 57 M7 Paper Feed Motor Drives the paper feed rollers, relay

M8 Registration Motor Turns the registration rollers. 72 M9 1st Lift Motor Lifts the first cassette’s bottom plate. 51 M10 2nd Lift Motor Lifts the second cassette’s bottom plate. 73 M11 Transport Vacuum Fan Provides suction so paper is held firmly

M13 OPC Drum Motor Turns the OPC drum. (servomotor) 77 M14 Transfer Drum Motor Turns the transfer drum. (servomotor) 84 M15 Transfer Drum

Cleaning Motor

M17 Transfer Exhaust Fan Removes the air around the transport

M18 Development Drive

Motor

M19 Cyan Development

Motor

M20 Magenta

Development Motor

M21 Yellow Development

Motor

M24 OPC Drum Cleaning

Motor

M25 Power Supply Cooling

Fan

M26 Charge Fan Provides a flow of air to the charge

M27 3rd Lift Motor Lifts the 3rd cassette’s bottom plate. 112

Positions the 2nd scanner based on the reproduction ratio. (stepper)

reproduction ratio. (stepper)

proper filter in the light path. (stepper)

rollers, transport belt, fusing rollers, and exit rollers. (encoder speed controlled)

on the transport belt.

Turns the transfer drum cleaning brush. 82

and the transfer drum sections. Drives the black development unit. In

reverse rotation, drives the color development units except the development roller sleeves.(encoder speed controlled)

Turns the cyan development roller sleeve. (encoder speed controlled)

Turns the magenta development roller sleeve. (encoder speed controlled)

Turns the yellow development roller sleeve. (encoder speed controlled)

Drives the OPC drum cleaning unit. (encoder speed controlled)

Cools the power supply unit. 62

corona unit to prevent uneven charge.

1-19

ELECTRICAL COMPONENT DESCRIPTIONS 20 December 1991

M28 Black Development

Motor

M29 Front Exhaust Fan Removes the air on the front side. 120

SOLENOIDS

SOL1 Pick-up Solenoid Controls the up-down movement of the

SOL2 Transfer Drum

Cleaning Solenoid

SOL3 Cleaning Support

Solenoid

SOL4 Paper Clamp Solenoid Opens and closes the transfer drum

SOL5 Pick-up Solenoid (3rd

paper feed)

MAGNETIC CLUTCHES

MC1 1st Feed Clutch Starts paper feed from the first feed

MC2 2nd Feed Clutch Starts paper feed from the second feed

MC3 Relay Roller Clutch Turns the relay rollers. 71 MC4 Black Toner Supply

Clutch

MC5 Cyan Toner Supply

Clutch

MC6 Magenta Toner

Supply Clutch

MC7 Yellow Toner Supply

Clutch

MC8 3rd Feed Clutch Starts paper feed from the 3rd feed

MC9 Relay Roller Clutch

(3rd paper feed)

Turns the black development roller sleeve.

pick-up rollers. Presses the transfer drum cleaning brush

against the transfer drum sheet during the transfer drum cleaning cycle.

Presses the cleaning support roller against the transfer drum sheet during the transfer drum cleaning cycle.

clamp. Controls the up-down movement of the

3rd pick-up roller.

station.

Turns the black toner supply roller. 95

Turns the cyan toner supply roller. 94

Turns the magenta toner supply roller. 93

Turns the yellow toner supply roller. 92

station Turns the 3rd relay roller. 113

116

107

108

SWITCHES

SW1 Main Switch Provides power to the copier. 38 SW2 Front Cover AC

Safety Switch

SW3 Front Cover DC

Safety Switch

Cuts AC power when the front cover is opened.

Cuts DC power when the front cover is opened.

1-20

20 December 1991 ELECTRICAL COMPONENT DESCRIPTIONS

SW4 3rd Paper Feed DC

Switch

SW5 3rd Paper Feed AC

Switch

SW6 Platen cover Closed

Switch

SENSORS

S1 1st Scanner HP

Sensor

S2 2nd Scanner HP

Sensor

S3 Lens HP Sensor Notifies the CPU when the lens is in the

S5 Filter HP Sensor Notifies the CPU when the filter is in the

S6 Auto Image Density

Sensor

S7 1st Paper End Sensor Informs the CPU when the first cassette

S8 2nd Paper End Sensor Informs the CPU when the second

S9 1st Paper Size Sensor Informs the CPU what size paper is in

S10 2nd Paper Size Sensor Informs the CPU what size paper is in

S11 1st Lift Sensor Detects the correct feed height of the first

S12 2nd Lift Sensor Detects the correct feed height of the

S13 Relay Sensor Controls paper feed clutch OFF timing. 29 S14 Registration Sensor Detects misfeeds and controls relay

S15 OHP Sensor Detects the OHP sheet. 25 S16 Transfer Drum HP

Sensor

S18 Black Toner Density

Sensor

S19 Cyan Toner Density

Sensor

S20 Magenta Toner

Density Sensor

Cuts DC power when the 3rd front cover is opened.

Cuts AC power when the 3rd front cover is opened.

Detects when the platen cover or the document feeder is closed, and gives the signal to perform original size detection with closed platen cover condition.

Notifies the CPU when the scanner is at the home position.

Notifies the CPU when the second scanner is at its home position.

home position.

home position. Senses the background density of the

original.

runs out of paper.

cassette runs out of paper.

the first cassette.

the second cassette.

cassette.

second cassette.

roller clutch OFF timing.

Informs the CPU when the transfer drum is in the home position.

Senses the amount of toner in the black developer.

Senses the amount of toner in the cyan developer.

Senses the amount of toner in the magenta developer.

105

118

1-21

ELECTRICAL COMPONENT DESCRIPTIONS 20 December 1991

S21 Yellow Toner Density

Sensor

S23 ID Sensor Detects the density of the image on the

Senses the amount of toner in the yellow developer.

drum.

S24 V

L Sensor Senses the density of the VL pattern on

18 the drum. This data is used to calculate drum residual voltage and drum illumination decay.

S26 Toner Overflow Sensor Detects when the used toner bottle is full. 8 S28 Pick-off Sensor Detects misfeeds. 26 S29 Exit Sensor Detects misfeeds. 104 S30 Oil End Sensor Detects when the silicone oil bottle is

103

empty.

S32 Cyan Dev. Motor

Sensor

S33 Magenta Dev. Motor

Sensor

S34 Yellow Dev. Motor

Sensor

S35 3rd Paper Size Sensor Informs the CPU what size paper is in

Monitors the speed and direction of the motor.

109

the 3rd cassette.

S36 3rd Paper End Sensor Informs the CPU when the 3rd cassette

111

runs out of paper.

S37 Relay Sensor (3rd

Paper Feed)

S38 3rd Lift Sensor Detects the correct feed height of the 3rd

Controls 3rd paper feed clutch OFF timing.

110

106

cassette.

S39 Multi By-pass Sensor Informs the CPU of the width of paper

115

which is in the multi by-pass tray.

S40 Original Width Sensor Detects the original width. 117 S41 Original Length Sensor Detects the original length. 119 S42 Platen Cover Position

Sensor

Gives the signal to perform original size detection with open platen cover

114

condition.

PCBs

PCB1 Main PCB Controls all machine functions. 19 PCB2 Servomotor PCB Controls the scanner motor, the OPC

20 drum motor, and the transfer drum motor.

PCB3 Motor PCB Controls eight DC motors. 12 PCB4 Process PCB Controls all corona and bias power

11 packs, AC drive unit sensors, and clutches in the development units, etc.

PCB5 DC Power PCB Provides DC power. 21

1-22

20 December 1991 ELECTRICAL COMPONENT DESCRIPTIONS

PCB6 AC Drive PCB Provides AC power to the exposure lamp

bulbs and the fusing lamp.

PCB7 Operation Panel PCB The user controls the machine through

this PCB.

PCB9 Transfer Drum

Interface PCB

LAMPS

L1 Exposure Lamp Unit Applies high intensity light to the original

L2 Erase Lamp Discharges the drum outside of the

L3 Pre-transfer Lamp

(PTL)

L4 Quenching Lamp Neutralizes any charge remaining on the

L5 Fusing Lamp (2 pcs) Provides heat to the hot roller. 102

POWER PACKS

PP1 Charge PP Provides high voltage for the charge

PP2 Separation PP Provides high voltage for the separation

PP3 Transfer PP Provides high voltage for the transfer

PP4 Transfer Drum

Cleaning PP

Interfaces the transfer drum cleaning motor/solenoid and the wire cleaner motor with the transfer power pack.

for exposure.

image area. Reduces the amount of charge on the

drum surface before transfer.

drum surface after cleaning.

corona wires and grill wires, the pre-cleaning corona, development bias, and cleaning bias.

corona and the outer AC and DC discharge coronas.

corona and the inner AC and DC discharge coronas.

Provides high voltage for the transfer drum cleaning bias.

HEATERS

H1 OPC Drum Heater Keeps the OPC drum warm to prevent

condensation on the drum.

H2 Anti-condensation

Heater

COUNTERS

CO1 Black Scan Counter Counts the number of black scans. 31 CO2 Color Scan Counter Counts the number of color scans. 30 CO4 Key Counter Used for control of authorized use.

Prevents moisture from condensing on the optics.

Copier will not operate until installed.

1-23

–

ELECTRICAL COMPONENT DESCRIPTIONS 20 December 1991

OTHERS

TH Fusing Thermistor Senses the temperature of the hot roller. 101 TF Fusing Thermofuse Opens the fusing lamp circuit if the fusing

unit overheats.

TS Drum Thermoswitch Activates when the drum temperature

becomes high to turn off the drum heater.

NF Noise Filter Removes electrical noise from the AC

input lines.

CB Circuit Breaker Guards against voltage surges in the AC

input lines.

RA Main Relay Provides AC power to the +24 volt circuit

of the DC power PCB and to the AC drive PCB after the main switch is turned on.

TR Transformer Drops the line voltage to 100 volts AC for

the sorter and the exposure lamp unit.

100

NOTE: Difference with A030 copier.

1. The following electrical compone nt s have been disco nt inu ed or newly added.

SYMBOL Discontinued components SYMBOL Added components

M 4 Light Shield Motor M28 Black Development Motor M12 Fusing Exhaust Fan M29 Front Exhaust Fan M16 Transfer Corona Wire Cleaner

Motor M22 Development Cooling Fan S39 Multi By-pass Sensor M23 Magnetic Shield Motor S40 Original Width Sensor

S 4 Light Shield HP Sensor S41 Original Length Sensor S17 Wire Cleaner HP Sensor S42 Platen Cover Position Sensor S22 Magnetic Shield HP Sensor S25 Cleaning Sensor S27 Cleaning Motor Pulse Sensor S31 Magnetic Shield Sensor

PCB8 Sorter Interface PCB

CO3 Total Copy Counter

SW6 Platen Cover Closed Switch

2. The second registrat ion sensor in the A030 copier is named as the OHP sensor (S16) in this A072 copier.

1-24

RICOH NC305

SECTION 2

DETAILED DESCRIPTIONS

7 November 1991 OPC DRUM

1. OPC DRUM

1.1 OPC DRUM CHARACTERISTICS

An OPC has the following characteristics:

• Able to accept a high negative electrical charg e in the dark. (The

electrical resistance of a photoco nd uct or is high in the absence of light.)

• Dissipates the electrical charge when exposed to light. (Exp osure to

light greatly increases th e conductivity of a photocond uct or.)

• The amount of charge dissipation is in direct proportion to the

intensity of the light. That is, whe re stro ng er ligh t is directed to the photoconductor surface , a smalle r voltage remains on the OPC.

• Unlike F type selenium drums, temperature compensation and rest

time compensation are not requ ired . Howe ver, some compensation for change in the drum’s residual voltage is required.

• Drum conditioning is required to maintain a high negative charge on

the drum surface.

2-1

+ 503 hidden pages

Ricoh NC305 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

IMPORTANT SAFETY NOTICES

PREVENTION OF PHYS ICAL INJURY

HEALTH SAFETY CONDITIONS

OBSERVANCE OF ELECTRICAL SAFETY STANDARDS

SAFETY AND ECOLOGICAL NOTES FOR DISP OS AL

OVERALL INFORMATION

DETAILED DESCRIPTIONS