Ricoh FT8880 Service manual

RICOH FT8880

SERVICE MANUAL

This manual is an insert upgrade which covers only the
points where the FT8880 (A083) differs from the FT8780
(A084). Refer to the FT8780 service manual for any items
not covered here.

IMPORTANT SAFETY NOTICES

PREVENTION OF PHYSICAL INJURY

1. While the machine warms up, it will suddenly start turning to perform the
process control data initialization. Keep hands away from any mechanical
and electrical components during this period.

2. Before disassembling or assembling parts of the copier and peripherals,
make sure that the copier and the second sorter power cord is unplugged.

3. The wall outlet should be near the copier and easily accessible.

4. Note that some components of the copier, the paper tray unit, and the
peripherals are supplied with electrical voltage even if the main switch is
turned off.

5. If any adjustment or operation 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 driven components.

6. The inside and the metal parts of the fusing unit become extremely hot
while the copier is operating. Be careful 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 specified
intervals.

3. Toner and developer are non-toxic, but if you get either of them in your
eyes by accident, it may cause temporary eye discomfort. Try to remove
with eye drops or flush with water as first aid. If unsuccessful, get medical
attention.

OBSERVANCE OF ELECTRICAL SAFETY STANDARDS

1. The copier and its peripherals must be installed and maintained by a
customer service representative who has completed the training course
on those models.

2. The RAM board on the main control boards on the copier and the RDH
has a lithium battery which can explode if replaced incorrectly. Replace
the battery only with an identical one. The manufacturer recommends
replacing the entire RAM board. Do not recharge or burn this battery.
Used batteries must be handled in accordance with local regulations.

SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL

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 toner, developer, and photoconductors according to
local regulations.

3. Dispose of replaced parts in accordance with local regulations.

4. When keeping used lithium batteries in order to dispose of them later, do
not put more than 100 batteries per sealed box. Storing larger numbers or
not sealing them apart may lead to chemical reactions and heat build-up.

SECTION 1

OVERALL MACHINE

INFORMATION

Overall

Information

5 June 1992 SPECIFICATIONS

1. SPECIFICATIONS

Main Copier

Copier

Configuration: Console
Copy Process: Dry Electrostatic Transfer System
Originals: Sheet/Book
Original Size: Maximum: 11" x 17", A3
Copy Paper Size: Maximum: 1st and 2nd tray 8

1/2" x 14", A4

3rd tray 11" x 17", A3

Minimum: 1st and 3rd tray 5

2nd tray 8

1/2" x 81/2", A5
1/2" x 11", A4

Copy Paper Weight: Standard Copying: 14 ~ 42 lb, 52 ~ 157 g/m

Duplex Copying: 17 ~ 28 lb, 64 ~ 105 g/m
Warm Up Time: Within 8.0 minutes (room temp. 68°F, 20°C)
First Copy Time: 4.8 seconds (8
Copying Speed: 80 copies/minute (8

1/2" x 11", A4, feed from 2nd tray)

1/2" x 11", A4)

60 copies/minute (11" x 17", A3)
Optional Equipment: Menu Reader

Key Counter

Guidance ROM Kit
Reproduction Ratios: See the following table:

LT/DLT version A4/A3 version

200% 200%

Enlargement

155% 141%
129% 122%
121% 115%

Full Size 100% 100%

93% 93%
77% 82%

Reduction

74% 71%
65% 65%
50% 50%

2
2

1-1

SPECIFICATIONS 5 June 1992

Zoom: 50 ~ 200%
Toner Replenishment: Cartridge exchange (1,500 g)
Paper Feed: 1st tray (550 sheets)

2nd tray (3,000 sheets)
3rd tray (1,500 Sheets)

Power Source: 120 V, more than 20 A (LT/DLT version)

220, 230, 240 V, more than 10 A (A4/A3 version)

Power Consumption:

Maximum during LT/DLT version A4/A3 version

Stand-by 2.01 kw 2.00 kw

Copying Cycle 1.85 kw 1.89 kw

Dimensions: Copier Only: 65.4" x 30.0" x 56.9"

(1660 x 760 x 1444.5 mm)

With Finisher: 83.1" x 30.0" x 56.9"

(2110 x 760 x 1444.5 mm)

Weight: Copier Only: 917 lb/422 kg

With Finisher: 1027 lb/472 kg

Noise Emission: With Finisher/RDH:

Maximum: less than 70 db
Copy-cycle: less than 69 db (average)
Warm-up: less than 42 db

1-2

Overall

Information

5 June 1992 SPECIFICATIONS

Recycling Document Handler

Original Size:

Stack feed mode Single feed mode CFF mode

Maximum 11" x 17", A3 11" x 17", A3 11" x 9

Minimum 8" x 10

Original Weight:

Stack feed mode Single feed mode CFF mode

Maximum 28 lb, 105 g/m

Minimum 17 lb, 64 g/m

Number of originals to be set:

Weight

Size

A3/11" x 17" 30 sheets 20 sheets

Others 50 sheets 30 sheets

1/2", A4 51/2" x 81/2", A5

2

43 lb, 165 g/m

2

14 lb, 52 g/m

64~81 g/m

2

17~21 lb

2

20 lb, 80 g/m

2

17 lb, 64 g/m

82~105 g/m

22~28 lb

8

1/2" x 12"

11" x 14

1/2"

7/8"

2

2

2

Number of Recycles: Maximum: 60 times
CFF Original Stack Height:Maximum: 50 mm
Original Set: First sheet on top, stack face down

1-3

MECHANICAL COMPONENT LAYOUT 5 June 1992

3. MECHANICAL COMPONENT LAYOUT

3.2 RDH

15

1

2

14 13 12 10 9

3 4 5

11

6

7

8

1. Inverter Roller

2. Inverter Exit Roller

3. Air Knife Nozzle

4. Exit Roller

5. Original Guide

6. Feed-in Belt

7. Original Stopper

8. Right Turn Roller

9. Belt Drive Roller

10. Transport Belt

11. Transport Rollers

12. Original Feed Roller

13. Inverter Entrance Roller

14. Single Feed Exit Gate

15. Inverter Middle Roller

1-4

Overall

Information

5 June 1992 ELECTRICAL COMPONENT DESCRIPTIONS

4. ELECTRICAL COMPONENT DESCRIPTIONS

Refer to the electrical component layout on the reverse side of the Point to
Point (Water proof paper) index numbers.

4.2 RDH

Name Function Index No.

Motors

Feed Drives the feed and transport rollers. 3
Belt Drive Drives the transport belt. 7
Inverter Drives the inverter and exit rollers. 34
Blower Supplies air to the air knife and draws air from the

vacuum section.

Separator Drives the original separator. 21

Sensors

Original Set Detects if the original is set on the document handler. 31
Entrance Detects the original leading edge and de-energizes

the feed belt drive clutch.
1st Transport Detects jams in the transport section. 16
2nd Transport Detects the original leading edge and lowers the

original feed motor speed.
Registration Detects the original trailing edge for the original stop

position calculation.
Inverter Entrance Detects jams in the transport belt section. 24
1st Inverter Detects the original trailing edge and reverses the

inverter drive motor rotation.
2nd Inverter Detects the original leading edge and energizes exit

roller release solenoid.
Exit Detects the original leading edge and lowers the

inverter drive motor speed.
Single Feed Set Detects the leading edge of the original in the single

feed table and turns the original feed motor.
Single Feed Exit Detects jams in single feed mode. 25
Lift Detects if the RDH is open. 2
CFF Detects if the computer form is set in the CFF guide.

Counts the holes lined up to the computer form.
Original Length Detects if the original stopper is set for 8
Original Height Detects the original height on the RDH. 20
Separator H.P. Detects if the original separator is in the home

position.
Separator Detects if the last original of the original stack is fed. 23
Inverter Unit Cover

(Switch)
Original Width

(Potentiometer)

Detect if the inverter unit cover is opened.

Detects the original width in the stack feed mode.

1/2" position. 19

5

33

15

12

29

30

32

13

9

22

27

17

1-5

ELECTRICAL COMPONENT DESCRIPTIONS 5 June 1992

Name Function Index No.

Single Feed Original
Width (Potentiometer)

Detects the original width in the single feed mode.

14

Solenoids

Vacuum Shutter Closes the vacuum shutter. 4
Single Feed Gate Lowers the single feed gate. 8
Single Feed Exit Lifts the single feed exit gate. 26
Exit Roller Releases the exit driven rollers from the exit drive

rollers.

28

Clutches

Feed Belt Drive Transmits the original feed motor drive to the feed

belt rollers.

10

Feed Belt Brake Stops the feed belt rotation. 11

PCBs

Main Control Controls overall RDH operation. 6
Blower Motor Control Controls the vacuum motor operation. 1
Indicator Indicates the single feed mode indicators. 18

1-6

SECTION 2

DETAILED SECTION

DESCRIPTIONS

5 June 1992 DEVELOPMENT

6. DEVELOPMENT

6.4.3 Bias for the ID Sensor Pattern

ID Sensor

Full Size

Enlargement

Reduction

VL Pattern

ID Sensor Pattern

Detailed

Descriptions

Exposure Glass

Outside

The ID sensor pattern cannot always be used for the image density detection
due to the position of the ID sensor and both the positioning and size of the
ID sensor pattern on the drum.
The outside of the exposure glass (no light) is exposed on the drum and used
as the ID sensor pattern in reduction mode.

The potential of the drum in these cases, the no light and the ID sensor
pattern exposure, is not the same. So the ID sensor bias (VBP) is determined
using two base voltages, V0 for the no-light condition and Vd for the pattern.

VBP (no light) = --360 + V0 (Reproduction ratio < 77%)
VBP (ID Pattern) = --360 + Vd (Reproduction ratio ≥ 77%)

The Vd value which is determined during the process control data
initialization will be used.

V01 and V02, which are explained in the process control section, are used for
the VBP calculation as the V0 (drum potential after the charge corona) value.

The VBP can be changed by the SP mode (Toner Density Correction).
The following compensation will be applied to the above VBP.

Setting L N H VH

(V) --60 0 +60 +120

Default: H (+60 V)

2-1

RDH 5 June 1992

16. RDH

16.1 OVERVIEW

16.1.1 No Inversion Original Cycle

[E] [B]

When the start key is pressed, the blower motor start to rotate. It supplies air
to the air knife and draws air from the vacuum section. Sheets are separated
at the leading edge [A] of the paper stack. The air comes from the nozzle [B]
and the bottom sheet of the stack paper is held against the feed-in belts [C]
by air suction [D]. The feed motor drives the feed drive [E], transport [F], and
right turn [G] rollers. The bottom sheet of the paper is delivered through the
feed drive, transport, right turn rollers to the registration section [H] and is
stopped. To stop the original sheet at the proper position in the registration
section, the feed motor rotation speed is reduced by half when the 2nd
transport sensor [I] detects the leading edge of the original. The belt drive
motor then starts to rotate the transport belt [J] to direct the sheet of paper
onto exposure glass. At the same time, the next original is fed.

[F]

[A]

[D]

[C]

[H]

[J] [I]

[G]

2-2

5 June 1992 RDH

[D]

[A]

[E]

[C]

[H]

[G]

[B]

[F]

Detailed

Descriptions

At the appropriate time, the transport belt delivers the original on the
exposure glass to the inverter section [A], and the following original is moved
onto the exposure glass, and the 3rd sheet of original is fed. The 1st original
is passed into the inverter section through the inverter entrance [B], inverter
middle [C], and inverter [D] rollers until the trailing edge of the original is
detected by the 1st inverter sensor [E]. The inverter middle [C] and inverter
[D] rollers then rotate in the opposite direction. The inverter exit rollers [F]
rotates only in the paper exit direction. However, the contact between the
inverter exit roller [F] and inverter exit driven roller [G] is released when the
2nd inverter sensor [H] is activated by the original. This way, the inverter exit
roller does not interfere with the original switch back cycle while the inverter
middle and inverter rollers begin reverse rotation. The original is delivered
through the inverter entrance [B] and inverter exit [F] rollers to the original
table. This continues until all originals have been returned to the original
table. The originals are stacked on the original table where they wait for the
next copy cycle.

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RDH 5 June 1992

16.1.2 Inversion Original Cycle

[A]

[B]

[B]

[C]

Until the original reaches to the inverter section [A], the sequence is the same
as for no inversion original cycle. The inverter rollers [B] rotate in the original
exit direction. The original is now inverted and exited to the original table [C].
This continues until all originals have been inverted. The inverted originals
are then fed from the original table for copying of the reverse side. The
sequence is the same as for the front side copying. The originals return and
are stacked on the original table where they wait for the next copy cycle.

2-4

5 June 1992 RDH

16.1.3 1 Sided Original 2 Sided Copy Mode

[A]

[B]

[C]

Detailed

Descriptions

No inversion original cycle is used for this mode.
All the originals [A] are fed starting from the bottom original sheet. First, odd

numbered originals (in case of the illustration: 1st and 3rd originals) are
copied and even numbered originals copy is skipped. The copied paper [B] is
stacked in the duplex tray. The originals are return to the original table, and
the original feed is then repeated. This time the odd numbered originals copy
is skipped and even numbered originals are copied on the reverse side of the
copy paper [C], which is fed from the duplex tray.

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RDH 5 June 1992

16.1.4 2 Sided Original 2 Sided Copy Mode

[A]

[B]

[C]

[D]

Inversion original cycle is used for this mode. All the originals [A] are fed
starting from the bottom original sheet. First, the front side of the originals are
copied. The copied paper [B] is stacked in the duplex tray. The originals [C]
are inverted and return to the original table. The original feed is then
repeated. This time the reverse side of the originals are copied on the
reverse side of the copy paper [D], which is fed from the duplex tray.

2-6

5 June 1992 RDH

16.1.5 2 Sided Original 1 Sided Copy Mode

[A]

[D]

[B]

Detailed

Descriptions

[C]

[E]

Inversion original cycle is used for this mode. All the originals [A] are fed
starting rom the bottom original sheet. Firstly, the front side of all the originals
are copied and the copied paper [B] is stacked in the duplex tray. The
originals [C] are inverted and return to the original table. The original feed is
then repeated. This time, the bottom copy sheet is fed from the duplex tray
and exited from the copier without copying [C]. The reverse side of the
bottom original sheet [D] is then copied to paper [E], which is fed from the
paper tray, and the copy is exited from the copier [E]. This copy sequence
exiting from the duplex tray followed by the paper tray is alternately repeated.

2-7

RDH 5 June 1992

16.2 ORIGINAL SET

16.2.1 Stack Feed Mode

[A]

[C]

[B]

[H]

[D]

[E]

[F]

[G]

1. Original set detection

The originals are detected by the original set sensor [A] when they are
stacked on the original table.

2. Size detection

The original width is detected by the original width sensor [B] under the front
original guide [C]. Moving the guide changes the value of the sensor. (The
sensor is a potentiometer.) The front original guide and rear original guide [D]
are moved by the racks [E] and pinion [F] at the same time. The actuator [G]
of the original stopper activates the original length sensor [H]
(photo-interrupter) to detect if the original stopper is set for the 81/2 inch
position. LG (81/2" x 14" = 216 x 356 mm) or B4 (257 x 364 mm) size is
distinguished by the combination of the original length sensor (activated or
not) and the value of the original width sensor. This is because the LG and
B4 widths are very close.

2-8

5 June 1992 RDH

[B]

[E]

[E]

[A]

[F]

Detailed

Descriptions

[D]

[C]

[E]

3. Original separator

The original stack which has been fed and returned to the original table, and
the original stack which has not been fed yet, are separated by the original
separator [A] mechanism.

When the start key is pressed, the separator motor [B] rotates until the
original separator actuator [C] activates the separator home position sensor
[D]. The original separator is set on the original top sheet. The originals which
are fed and returned to the original table are stacked on the original
separator. When the last original (top sheet under the original separator) is
fed from the original table, the original separator drops and activates the
separator sensor [E].

If the next copy cycle continues, the separator motor rotates and the original
separator is set on the original top sheet again after the trailing edge of the
last original sheet passes through the exit sensor [F].

2-9

RDH 5 June 1992

16.2.2 Single Feed Mode

[A]

[C]

[E]

[D]

[B]

[F]

1. Original set detection

The original is detected by the single feed set sensor [A] when the original is
set on the single feed table.

2. Size detection

The original width is detected by the single feed original width sensor [B]
under the rear original guide [C]. Moving the guide changes the value of the
sensor. (The sensor is a potentiometer.) The front original guide [D] and rear
original guide are moved by the racks [E] and pinion [F] at the same time. As
the original length sensor is not used for the single feed mode, the original
length is not detected. When the B4 or LG original is set on the single feed
table, the original size is determined by the machine version.
(U.S.A. version machine ... LG, Europe version machine ... B4).

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5 June 1992 RDH

16.3 ORIGINAL FEED

16.3.1 Original Separation/Feed (Original Stack Mode)

[A]

[B]

[E]

Detailed

Descriptions

[B]

[F]

[D]

[C]

[F]

[G]

[H]

1. Air knife and shutter

The air from the blower motor [A] is blown through the air knife nozzles [B] to
the leading edge [C] of the original stack. The blower motor keeps blowing air
from the beginning to the end of the original stack mode to prevent
multi-feeding.

After the originals are separated by the air knife, the vacuum shutter solenoid
[D] is energized by a paper feed signal from the main PCB. The vacuum
shutter [E] closes the air hole on the vacuum duct [F]. The blower draws air
from the vacuum section [F]. The bottom sheet original [G] is held against the
feed-in belts by the suction. Until, the feed-in belt rotates. The bottom sheet
original [H] is then fed.

2-11

RDH 5 June 1992

[A]

Table 1

Table 2

Small

Size

Large

Size

Small

Size

Large

Size

A4
8 x 101/2
81/2 x 11
81/2 x 13

B4

A3
81/2 x 14

10 x 14
11 x 17

A4
8 x 101/2
81/2 x 11
81/2 x 13

B4

A3
81/2 x 14

10 x 14
11 x 17

Original Height Sensor

OFF ON

3000 rpm

6000 rpm

3500 rpm

Number of Originals

5 or less from 6 to 12 13 or more

3000 rpm

6000 rpm

3500 rpm

2. Blower motor speed

To ensure good original separation and original re-stacking on the original
table, the blower motor speed is changed according to the original stack
height, or the number of originals stacked. The blower motor speed is
determined for the 1st copy cycle by the original stack height as detected by
the original height sensor [A] (Table 1). From the 2nd copy cycle, the blower
motor speed is determined by the number of originals counted by the main
PCB (Table 2).

When the number of the originals is 3 or less, the original set sensor is
de-activated when the last original is fed and before the 1st original returns to
the original table. During this period the blower motor stops rotating to ensure
correct stacking the originals.

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5 June 1992 RDH

16.4 SINGLE FEED MODE

16.4.1 Registration

[D]

[E]

[B]

[A]

[C]

Detailed

Descriptions

[D]

When the single feed set sensor [A] detects the leading edge of the original
the feed motor rotates and the right turn roller [B] transports the original. At
the same time the single feed gate solenoid [C] is energized and the single
feed gate [D] is lowered. The feed motor and single feed gate solenoid are
energized until the registration sensor [E] detects the leading edge of the
original. The original is transported until hits the single feed gate, which
corrects the original feed skew. At the same time the right turn roller stops
rotating.

2-13

RDH 5 June 1992

16.4.2 Feed

[C]

[B]

[D]

[G]

[A]

[F]

[E]

When the start key is pressed, the right turn roller [A] and transport belt [B]
rotate. The original is delivered onto the exposure glass. After the scanner
scans the original, the transport belt start to rotate to deliver it. At the same
time the inverter entrance [C] and inverter middle [D] rollers rotate and the
single feed exit solenoid [E] is energized. The single feed exit gate [F] lifts up,
exiting the original to the left top cover [G].

16.4.3 Exit Gate

In single feed mode and CFF mode, the single feed exit solenoid is energized
while the belt drive motor is driving the transport belt, and is de-energized
when the transport belt stops rotating. This solenoid on off operation is
performed to keep the solenoid reliable.

2-14

5 June 1992 RDH

16.5 DRIVE MECHANISM

16.5.1 Feed Motor Drive

[H]

[A]

[D]

[B]

[A]

[G]

[C]

Detailed

Descriptions

[H]

[E]

[F]

[C]

All the feed rollers and transport rollers (with the exception of the feed belt
drive rollers [A]) begin to rotate together with the feed motor [B]. The feed belt
drive clutch [C] is energized according to the appropriate original feed timing.
When the clutch is energized, the feed motor drive will be transmitted through
the gears [D] and timing belt [E], and the feed belt brake clutch shaft [F] to
the feed belt drive rollers. The feed belt brake clutch [G] stops the feed belt
rotation when the feed belt drive clutch is de-energized to prevent
multi-feeding of originals. When the feed belt brake clutch is energized,the
rotating clutch disk [H] is stopped by the clutch which is fixed on the frame.

2-15

RDH 5 June 1992

16.5.2 Belt Drive Motor Drive

[B]

[A]

The transport belt [A] is driven by the belt drive motor [B] via timing belts and
pulleys.

2-16

5 June 1992 RDH

16.5.3 Inverter Motor Drive

[C]

[B]

[D]

[E] [F]

[A]

[H]

Detailed

Descriptions

[G]

[D]

[A]

The inverter motor [A] rotates forwards or backwards according to the
appropriate timing. The inverter middle [B] and inverter [C] rollers rotate
forwards and backwards the inverter motor drive. However, inverter entrance
[D], inverter exit [E], and exit [F] rollers rotate in only one direction.

The relay pulley [G] and inverter roller pulley [H] have a built- in one way
clutch inside. When the inverter motor rotates forwards (black arrow
direction), the inverter roller pulley [H] rotates the inverter entrance roller [D].
In this case the relay pulley [G] freely rotates due to the one way clutch
inside. All rollers rotate in the original feed direction.

While the inverter motor rotates backwards (white arrow direction), the relay
pulley [G] rotates the inverter entrance roller [D]. In this case the inverter
roller pulley [H] freely rotates due to the one way clutch inside. The inverter
entrance, inverter exit, and exit rollers rotate in the original exit direction.
However, the inverter middle and inverter rollers rotate in the original
switching back direction.

2-17

RDH 5 June 1992

16.6 ORIGINAL POSITIONING

Thin Paper Mode

Thick Paper Mode

Customers can choose the paper transport mode by "User Tool" depending
on the thickness of the original used.

-- In thin paper mode --

The belt motor stops exactly when the trailing edge of the original passes the
right scale [A] edge. (The timing is measured by the timing sensor after
registration sensor is activated.)

-- In thick paper mode --

To correct skewing on the exposure glass, the original runs 10 mm after the
trailing edge passes the right scale. The belt motor then reverses and the
original travels until it meets the right scale.

If extremely thin paper is used in the thick paper mode, the paper may float
near the scale. This will result in poor image quality or original copy wrinkling.

The factory setting is "Thin Paper Mode:.

2-18

5 June 1992 RDH

16.7 CFF Mode

[C]

[A]

Detailed

Descriptions

[E]

[D]

[B]

When the CFF guide lever [A] is slid to the left, the CFF sensor [B] comes out
of the single feed rear guide [C]. This sensor consists of one CFF set sensor
[D] and two CFF feed hole sensors [E]. The CFF set sensor [D] and two CFF
feed hole sensors [E]. The CFF set sensor detects if the computer form is set
in the CFF guide.

The CFF feed hole sensor counts the holes lined up to the computer form.

2-19