Oki C911 DICOM User manual

C911 / C931 / C941
Maintenance Manual
120213B

Copyright Information
Copyright © 2013 by Oki Data. All Rights Reserved
Disclaimer
Every effort has been made to ensure that the information in this document is complete, accurate, and up-to-
date. The manufacturer assumes no responsibility for the results of errors beyond its control. The
manufacturer also cannot guarantee that changes in software and equipment made by other manufacturers and
referred to in this guide will not affect the applicability of the information in it. Mention of software products
manufactured by other companies does not necessarily constitute endorsement by the manufacturer.
While all reasonable efforts have been made to make this document as accurate and helpful as possible, we
make no warranty of any kind, expressed or implied, as to the accuracy or completeness of the information
contained herein.
The most up-to-date drivers and manuals are available from the web site:
http://www.okiprintingsolutions.com

45530603TH Rev.2 3
Oki Data CONFIDENTIAL
This manual provides an overview of method for maintaining the C911/C931/C941/
ES9411/ES9431/ES9541 series.
This manual is intended for maintenance staff. For more information about how to operate
the C911/C931/C941/ES9411/ES9431/ES9541 series, please refer to User 's manual.
Note! • Manual may be revised and updated at any time without notice.
• Unexpected mistakes may exist in the manual.
OKI will not assume any responsibility whatsoever for damage to the
equipmentrepaired/adjusted/changed by the user etc with this manual.
• The parts used for this printer may be damaged when handling
inappropriately. We strongly recommend maintaining this apparatus by
our registration maintenance staff.
• Please operate the apparatus after removing static electricity.
PREFACE
Risk of explosion if battery is replaced by an incorrect method.
Dispose of the used battery in accordance with local regulations.

45530603TH Rev.2 4
Oki Data CONFIDENTIAL
Index
1. CONFIGURATION ................................................................. 1-1
1.1 System configuration ......................................................................................... 1-2
1.2 Printer configuration ..........................................................................................1-4
1.3 Composition of optional items ...........................................................................1-5
1.4 Specifications ....................................................................................................1-6
1.5 Interface specifications ......................................................................................1-9
1.5.1 USB interface specifications ......................................................................1-9
1.5.1.1 USB interface overview.......................................................................1-9
1.5.1.2 USB interface connectors and cables.................................................1-9
1.5.1.3 USB interface signals .........................................................................1-9
1.5.2 Network interface specifications ..............................................................1-10
1.5.2.1 Network interface overview...............................................................1-10
1.5.2.2 Connector and cable of network interface ........................................1-10
1.5.2.3 Network interface signals..................................................................1-10
2. DESCRIPTION OF OPERATION...........................................2-1
2.1 Electrophotographic process mechanism..........................................................2-2
2.2 Printing process.................................................................................................2-5
2.3 Low-voltage Power Supply ..............................................................................2-17
2.3.1 Operation .................................................................................................2-17
2.3.2 Power-supply Voltage in Each Mode........................................................2-17
2.3.3 Thermistor for Temperature Alarm ...........................................................2-17
2.4 Cover Opening and Closing Detection Switch.................................................2-18
2.5 Initialization processing ...................................................................................2-19
3. INSTALLATION .....................................................................3-1
3.1 Cautions, and do’s and don’ts ...........................................................................3-2
3.2 Installation instructions ......................................................................................3-3
3.3 Cautions for mounting expansion tray units.......................................................3-4
3.4 Cautions for Banner Tray ...................................................................................3-7
3.5 Cautions for Packing........................................................................................3-10
4. TROUBLESHOOTING PROCEDURE...................................4-1
4.1 Important notes to start the repair work ............................................................4-2
4.2 Matters to be checked before taking corrective actions against abnormalities .4-2
4.3 Precautions when taking corrective actions against abnormalities ...................4-2
4.4 Preparation for troubleshooting .........................................................................4-2
4.5 Troubleshooting methods ..................................................................................4-3
4.5.1 LCD message list.......................................................................................4-3
4.5.2 Preparation for troubleshooting................................................................4-36
4.5.3 Troubleshooting the abnormal images.....................................................4-80
4.5.4 Network troubleshooting ..........................................................................4-87
4.6 Fuse check ......................................................................................................4-89
4.7 Paper cassette switches and paper size correlation table...............................4-96
5. MAINTENANCE MENUS.......................................................5-1
5.1 System maintenance menu (for maintenance personnel) ................................5-2
5.2 Maintenance Utility ............................................................................................5-3
5.3 User maintenance menu functions....................................................................5-5
5.3.1 Maintenance menu (for end-users)............................................................5-5
5.3.2 Self-diagnostic mode ...............................................................................5-16
5.3.2.1 Operator panel..................................................................................5-16
5.3.2.2 Normal self-diagnostic mode (Level 1) .............................................5-19
5.3.2.2.1 Entering self-diagnostic mode (level 1)..........................................5-19
5.3.2.2.2 Exiting self-diagnostic mode ..........................................................5-19
5.3.2.3 Switch scan test................................................................................5-20
5.3.2.4 Motor and clutch test ........................................................................5-25
5.3.2.5 Test print ...........................................................................................5-28
5.3.2.6 Color registration adjustment test .....................................................5-32
5.3.2.7 Density adjustment test ....................................................................5-37
5.3.2.8 Adjustment of Media Thickness Sensor............................................5-40
5.3.2.9 Adjustment of Paper Width Sensor...................................................5-46
5.3.2.10 Consumable counter display.............................................................5-49
5.3.2.11 Print counter display .........................................................................5-50
5.3.2.12 Factory-Shipping mode switching ....................................................5-50
5.3.2.13 Self-diagnostic function setting ........................................................5-51
5.3.2.14 LED head serial number display ......................................................5-52
5.3.2.15 Drum Manual Cleaning ....................................................................5-52
5.3.2.16 Error code display ............................................................................5-53

45530603TH Rev.2 5
Oki Data CONFIDENTIAL
5.3.3 Printing on stand-alone basis...................................................................5-54
5.3.4 Button-pressed functions at power-on .....................................................5-54
5.4 Setup after part replacement...........................................................................5-55
5.4.1 Notes on PU/ CU board replacement ......................................................5-55
5.5 Manual density adjustment setting ..................................................................5-57
5.6 Boot Menu List.................................................................................................5-58
6. REPLACEMENT OF PARTS .................................................6-1
6.1 Notes on replacement of parts ..........................................................................6-2
6.2 Part replacement procedure..............................................................................6-4
6.2.1 Toner Cartridge .......................................................................................... 6-4
6.2.2 Image Drum ...............................................................................................6-4
6.2.3 Belt Unit .....................................................................................................6-6
6.2.4 Transfer roller unit ......................................................................................6-8
6.2.5 Fuser unit ..................................................................................................6-9
6.2.6 Waste toner box ......................................................................................6-10
6.2.7 LED Head ................................................................................................6-11
6.2.8 Cassette-Assy/Guide-Assy-Tail/Label-Tray/Indicator-Paper-Size ............6-13
6.2.9 Cover-Assy-TC.........................................................................................6-14
6.2.10 Cover-Assy-OP-Panel..............................................................................6-14
6.2.11 Lever-Stacker-Full....................................................................................6-15
6.2.12 Eject-Assy-Joboff/Motor-Joboff................................................................6-15
6.2.13 Guide-Assy-Eject-M ................................................................................. 6-16
6.2.14 Sheet-OP-Panel/Plate-Logo/Plate-Name.................................................6-16
6.2.15 Cover-Assy-Top-B....................................................................................6-17
6.2.16 Duplex-Unit ..............................................................................................6-17
6.2.17 Duplex-Board(Board-FIT-1)(Duplex unit control PCB) .............................6-18
6.2.18 Cover-Assy-Front.....................................................................................6-18
6.2.19 Filter-Front/Motor-FAN/Board-F1E(External LED PCB) ..........................6-19
6.2.20 Board-F1D(Driver relay PCB)/Board-F1Y(PU/CU PCB)/
Board-F1X(Spot color PCB) /Board-Memory/FAN .................................6-19
6.2.21 Board-AHV( High-voltage power supply PCB).........................................6-20
6.2.22 Motor-Assy-ID..........................................................................................6-20
6.2.23 Board-AHR(High-voltage relay PCB).......................................................6-21
6.2.24 Board-TAGRW/FFC-Cable/Motor-FAN.....................................................6-21
6.2.25 Low-Voltage-Power-Unit/Low-Voltage-FAN/Geard-Motor ........................6-22
6.2.26 Paper size sensor ....................................................................................6-22
6.2.27 Belt-Drive-Assy/Fuser-Drive-Assy/Belt-Mini-Pitch ...................................6-23
6.2.28 MPT-Unit ..................................................................................................6-23
6.2.29 Hopper-Assy/Board-F1S(MPT relay PCB)...............................................6-24
6.2.30 Clutch(Feeder-Assy) ................................................................................6-24
6.2.31 Frame-Assy-TC/Frame-Assy-TC-R..........................................................6-25
6.2.32 Plate-Fix-Pivot..........................................................................................6-26
6.2.33 Board-F1H(Print head power relay PCB)/Board-MFH(Environmental sensor PCB)/
Board-F1G(Tag terminal PCB)/ Board-F1N(Toner-low sensor PCB)..................6-27
6.2.34 Motor-Assy-Geard....................................................................................6-27
6.2.35 EJ-Rail-Unit .............................................................................................6-28
6.2.36 Guide-Assy-Eject-Lower-SP/Frame-Assy-TR2/Decurl-Assy ...................6-28
6.2.37 Gear-Assy-Oneway-Z33/Gear-Assy-Oneway-Z33-R/
Board-F1L(Rail unit relay PCB) ..............................................................6-29
6.2.38 Slide-Rail-Assy ........................................................................................6-30
6.2.39 Roller-Assy-Regist-2/Roller-Assy-Synchro/Regist-Sensor-Assy_753 .....6-30
6.2.40 Waste toner full sensor Board-F1N(Toner Low sensor PCB) ..................6-31
6.2.41 Motor-Assy-Regist ................................................................................... 6-31
6.2.42 Connector-Assy-Fuser.............................................................................6-32
6.2.43 Hopping-Unit............................................................................................6-32
6.2.44 Roller-Assy-Regist-T ...............................................................................6-33
6.2.45 Board-F1K(Cassette sensor relay PCB)..................................................6-33
6.2.46 Board-F1W(Soft switch PCB) ..................................................................6-34
6.2.47 Sensor-Assy-Front/Motor-FAN ................................................................6-34
6.2.48 Holder-Head-F/Holder-Head-R................................................................6-35
6.2.49 Paper Feed Roller....................................................................................6-35
6.3 Portions Lubricated..........................................................................................6-38
7. PERIODIC MAINTENANCE .................................................. 7-1
7.1 Cleaning ............................................................................................................7-2
7.2 Cleaning the LED lens array..............................................................................7-3
7.3 Cleaning feed rollers..........................................................................................7-8
7.4 Cleaning feed rollers of the Multi-purpose Tray ...............................................7-10
7.5 Cleaning Belt Unit............................................................................................7-13
7.6 Cleaning Pinch rollers......................................................................................7-14
7.7 Cleaning Transfer roller unit and paper feeding route......................................7-15
8. CONNECTION DIAGRAMS...................................................8-1
8.1 Resistance value check.....................................................................................8-2
8.2 Parts location.....................................................................................................8-9

Oki Data CONFIDENTIAL
1. CONFIGURATION
1.1 System configuration ................................................................1-2
1.2 Printer configuration .................................................................1-4
1.3 Composition of optional items ..................................................1-5
1.4 Specifications ............................................................................1-6
1.5 Interface specifications ..............................................................1-9

45530603TH Rev.2 1-2
Oki Data CONFIDENTIAL 1. CONFIGURATION
Color LCD Board(F1P)
Main Board(F1Y)
CE1-Main
High Volt(AHV)
DDR3-RAM
SODIMM x 12GB
NAND Flash
1Gbit
SPI Flash
16Mbit
EEPROM
64K
DDR3 RAM
512MB(ON Board)
LED HEAD Y
LED HEAD M
LED HEAD C
LED HEAD K
SPI Flash
8Mbit
ID-UP sensor input
Driving parts
・Fuser/Belt/Hop/Feed Motor
・1st/MPT/DUP/Resist Clutch
・FU/Dup Solenoid
・PU FAN
ONLINE
SW
ONLINE
LED
Panel
CPU
Design
LED(blue)
Soft SW,
LED
Front,TC
Cover SW
CU FAN
Option HDD
160GB
RTC, Battery
Initial Status
LED
Machine Sensor
・Paper feed
・Position
・Tray,Stacker
Analog Sensor
・Color regist, Density
・Fuser thermistor
・Env sensor
・Pow-nuit temp
Sub Board(F1X)
G-LAN PHY
USB2.0
Device CN
Giga-LAN CN
EEPROM
EMF-Main
32K
Tag cont
board
Engine
cnt
ARM7
AD
conv
IO
port
Fuser
cont
UART
H-Volt
CPU
Duplex board(F1T-1)
Dup-cnt
CPU
Op-Tray board(F1T-2)
OPT-cnt
CPU
Fuser
・Control
・Temp
Port-cnt
CPU
・Power/PU/Second transfer FAN
・Left/Side/MPT cover
・Paper size
・Paper width,Paper thick sensor
Driver Board(F1D)
Driver
CPU
CE1-Sub
EMF-Sub
LED HEAD W
DDR3 RAM
512MB(ON Board)
24V
5V(main)
5V(Sub)
Low-Voltage Unit
Fuser power
Head power
AC
Soft-SW input
Front,TC cover-SW
ID, Toner control
・ID motor,solenoid
・Up/Down sensor
・Toner supply motor
・ID/Fuser FAN
・Belt thermistor
Rear control
・Job-off motor
・Cover sensor
Op-Tray cont
・Feed/Carrier motor
・Hop/Reg clutch
・Cassette sensor
Duplex cont
・
Dup motor
・
2pass Separator solenoid
・
DUPFAN
H-Volt cont
・ID H-Volt
・Front-cover
24V/5V Main
ON signal
W/Clear printing
timing cont
Tag
For 4 color model, these component aren’t included(F1X board and LED Head
)
Power
Auto Off
CPU
cnt
PowerLED
ON_LINE SW,ON_LineLED
Power-On Device in Deepsleep
Sub-Microcomputer (R8C)
CPU
MV78260
Board or Unit
Figure 1-1
1.1 System configuration
Figure 1-1 represents the system configuration of the apparatus.
Ta b le 1 - 1 s h o w s t h e P C B l i s t o f C 9 1 1 / C 9 31 / C 9 4 1 / E S9 4 1 1 / ES 9 4 3 1 / E S 9 5 41 .

45530603TH Rev.2 1-3
Oki Data CONFIDENTIAL 1. CONFIGURATION
Ta b le 1 - 1 P C B l i s t o f C 9 11 / C 9 3 1 / C9 4 1 / E S 9 4 11 / E S 9 4 31 / E S 9 5 4 1
No Name Purpose Remarks
1 F1Y Printer controller (PU/CU) For five-color models
2 F1Y-2 Printer controller (PU/CU) For four-color models
3 F1X Spot color control Used for five-color models only.
4 F1D Driver relay For five-color models
5 F1D-2 Driver relay For four-color models
6 F1T-1 Duplex unit control
7 F1T-2 Optional tray units control
8 F1P or F1A Control panel control
9 F1E External LED
10 F1G Tag terminal
11 F1H Head power relay
12 F1K Cassette sensor relay Common to the main unit and option trays
13 F1L EJ-Rail unit relay
14 F1N Toner-low sensor, Waste-toner-full sensor
15 F1S MPT relay
16 F1W Soft switch
17 AHV-1 High-voltage power supply For five-color models
18 AHV-2 High-voltage power supply For four-color models
19 PWR unit-ACDC Switch Low-voltage power supply
20 AHR High-voltage relay
21 F1B Belt thermistor relay Consisted in the belt unit
22 MFH Environmental sensor

45530603TH Rev.2 1-4
Oki Data CONFIDENTIAL 1. CONFIGURATION
1.2 Printer configuration
The internal part of the printer is composed of the following sections:
• Electrophotographic processing section
• Paper paths
• Controller (a combination PU/CU board)
• Operator panel
• Power supplies (high-voltage power supply/low-voltage power supply)
Figure 1-2 represents the configuration of the printer.
Figure 1-2

45530603TH Rev.2 1-5
Oki Data CONFIDENTIAL 1. CONFIGURATION
1.3 Composition of optional items
The following optional items are available for the apparatus.
(1) Optional Tray Unit
(4) Internal hard disk
(2) Optional Tray Unit with Casters
(3) High-capacity Optional Tray Unit (three-layer of optional trays integrated unit with Casters)
(5) Spot-color kit (5-Color models only)
(6) Banner Tray

45530603TH Rev.2 1-6
Oki Data CONFIDENTIAL 1. CONFIGURATION
1.4 Specifications
Classification Item
Specification
C911dn/C931dn/
ES9411dn/ES9431dn C941dn/ES9541dn
Dimension Width 699mm
Depth 625mm(665mm/Operator panel including dimension)
Height 640mm
Weight Approx. 96.5kg Approx. 116.5kg
Printing width Printing width Max. 328mm
Print speed Engine speed 50PPM(A4 LEF)
(community color and mono printing)
Print start First print time 8 sec. (community color and mono printing) (A4 LEF)
Warm-up time From power on: 50 seconds
From power on (with Calibrations): 110 seconds or less
From power save mode: 35 seconds
Resolution LED head 1200dpi
Maximum input
resolution
1200 ×1200dpi
Output resolution True 1200 ×1200 dpi
True 600 ×600 dpi
1200 ×600 dpi 4 bit
Gradation 1,200 dpi, two gradations
Toner save mode
Ton e r c o n s u mp t i o n s a v i n g b y t o d e c r e a s e for pr i n t i n g d e n s i t y
CPU Core ARM processor
Clock 1GHz(C911/ES9411)/
1.2GHz(C931)
1.2GHz
RAM Resident 2GB
ROM Program + font 128MB
Classification Item
Specification
C911dn/C931dn/
ES9411dn/ES9431dn C941dn/ES9541dn
Power
consumption
Power input ODA, ODB : 120V AC +/-10%
OEL, ODA230, AOS, Korea, China : 230V AC +/-10%
Off mode 【100 〜127V】≦0.4W
【220 〜240V】≦0.5W
Sleep mode 4.0W or less (Factory default)
Power save mode 【100 〜127V】≦30W w/o option
【220 〜240V】≦34W w/o option
Idle 40W (average)
Normal operation 1100W (average)
(Varies depending on usage environment)
Peak 1600W
Operating
environment
(temperature)
Operating 10°C to 32°C,
17°C to 27°C (temperature with assurance of the
quality for full-color printing)
Non-operating 0°C to 43°C, power off
Storage (one year
max.)
-10°C to 43°C, with drums and toner cartridges
Transportation (one
month max.)
-29°C to 50°C, with drums but no toner cartridges
Transportation (one
month max.)
-29°C to 50°C, with drums and toner cartridges
Operating
environment
(humidity)
Operating 20% to 80%,
50% to 70% (humidity for full-color print quality
guaranteed)
Maximum wet-bulb temperature: 25°C
Non-operating 10% to 90%,
maximum wet-bulb temperature: 26.8°C, power-off
Storage 10% to 90%,
maximum wet-bulb temperature: 35°C
transportation 10% to 90%,
maximum wet-bulb temperature: 40°C

45530603TH Rev.2 1-7
Oki Data CONFIDENTIAL 1. CONFIGURATION
Classification Item
Specification
C911dn/C931dn/
ES9411dn/ES9431dn C941dn/ES9541dn
Life Printer life 1,500,000pages (A4 LEF), five years
Monthly Duty Cycle
(M=L/12, A=L/12/5)
Max.300,000 pages/month
Average 25,000 pages/month
MTBF (2.3% duty) 6,000H (reference)
MPBF 140,000 pages
MTTR Within 20 minutes
Toner life
(based on ISO/IEC
19798)
(The spot color white/
clear is according to
A4 size with 5% area
coverage.)
Toner provided with the product:
10,000 pages (C/M/Y/K/ White*¹/ Clear*¹)
24,000 pages (C/M/Y/K)
38,000 pages (C/M/Y/K)
Standard: 10,000 pages (White*¹/ Clear*¹)
High capacity: 20,000 pages (Clear*¹),
24,000 pages (C/M/Y/K)
Ultra High Capacity: 38,000 pages (C/M/Y/K)
Image drum life 40,000 pages (3 pages/job, C/M/Y/K)
20,000 pages (3 pages/job, White*¹/Clear*¹)
20,000 pages (1 page/ job, C/M/Y/K)
10,000 pages (1 page/job, C/M/Y/K)
76,000 pages (when printed continuously, C/M/Y/K)
38,000 pages (when printed continuously, White*¹/
Clear*¹)
Counter : automatic reset
Transfer belt life 150,000 pages (A4 LEF, 3 pages/job)
counter : automatic reset
Fuser unit life 150,000 pages (A4 LEF)
counter : automatic reset
Operation
noise
Operating 57 dBA (ISO 7779 Front)
(without any optional unit)
Standby 32 dBA (ISO 7779 Front)
In one minute after printing (Factory default)
Sleep mode Background level
Classification Item
Specification
C911dn/C931dn/
ES9411dn/ES9431dn C941dn/ES9541dn
Paper
handling
Tray capacity (1st tray) Universal cassette: 580 sheets (64g/m2)
Tray capacity
(2nd/ 3rd/4th/5th tray)
Universal cassette: 580 sheets (64g/m2)
Tray capacity
(Multi purpose tray
(MPT))
310 sheets (64g/m2) (Total thick is 31mm or less)
Paper ejection 620 sheets (64g/m2) to the face down tray,
300 sheets (64g/m2) to the face-up tray
Duplex Standard
Paper size A3 nobi, A3Wide(SRA3), B6, Tabloid extra,
A4Wide(SRA4), A3, A4 [SEF/LEF], A5 [SEF/
LEF*], A6*, B4, B5 [SEF/LEF], Letter [SEF/LEF],
Legal (13in, 13.5in,14in), Tabloid, Executive
16K(184×260mm, 196×270mm, 197mm×273mm
[SEF/LEF]), 8K(260×368mm, 270×390mm,
273×394mm) Statement****, Envelope(Com-9,
Monarch, Com-10, DL, C5, C4)**, Postcard*,
Double postcard, Custom***, Japanese envelope
(Choukei 3, Choukei 4, Choukei 40, Youkei 0, Youkei
4, Kakugata 2, Kakugata 3, Youkei 2 (C6), Kakugata
8)**, Index card**, Banner, B6 half**.
*: Spot-color over print is unavailable for A6, A5LEF,
postcard, envelope, index card and B6 half.
**: Envelope, index card and B6 half can be used in
MPT and face-up stacker.
***: As for Custom, available size is different
depending on a tray.
****: statement can be used in Multi purpose tray
only.
Minimum
paper size
Tray 1 99 ×147mm
Tray 2, 3, 4, and 5
(Optional Tray)
Multi purpose tray 64 ×89mm
Media
weight
Tray 1 52g/m2to 320g/m2
Tray 2, Tray 3, Tray 4,
Tray5 (Optional Tray)
Multi purpose tray 52g/m2to 360g/m2

45530603TH Rev.2 1-8
Oki Data CONFIDENTIAL 1. CONFIGURATION
Classification Item
Specification
C911dn/C931dn/
ES9411dn/ES9431dn C941dn/ES9541dn
Operator
panel
LCD Graphic panel with 480 ×272 dots
With display of paper size
LED (Color) 5 LEDs (green ×2, dark amber ×2, Blue ×1)
Button 20 buttons
• Numeric-key pad
• Power Save button (green)
• Operational buttons (7 buttons: ON LINE (green),
CANCEL ,OK , , , BACK , HELP(Dark amber))
Status
switch/
sensor
Paper End Provided
Paper low Provided
Toner low Provided (Y, M, C, K, White (W), Clear (CL))
Top/front open Provided
Fuser temperature Provided
Paper size Provided (Auto detection)
Stacker full Provided
Communi-
cation
interface
Standard
(on-board)
•USB2.0 (High-speed USB is supported)
•Ethernet (1000BASE-T/100BASE-T/10BASE-T)
Page
description
language
Standard PCL6(PCL5c, PCLXL3.0) / XPS /
Direct PDF Printing(PDF1.7) / PostScript3 /
IBM PPR III XL / EPSON FX
Emulation switch Automatic
Font Bit-map font Provided
Scalable font Provided
Barcode Provided
OCR-A/B Provided
Classification Item
Specification
C911dn/C931dn/
ES9411dn/ES9431dn C941dn/ES9541dn
Option
(removable)
HDD kit
Installable by users
160GB
Tray configuration Tray 2/ Tray 3/ Tray 4/ Tray5
Cassette Universal (580 sheets, 64g/m2)
Banner Tray Provided
Tray with chasters Provided
Spot color kit Spot color kit (White (W), Clear (CL))
Shipping
setting
(by each to shipping
area)
PCL + PS model
(1200dpi LED Head model with all of PDLs)
Other USB-IF logo Provided
Windows logo Provided
Operation with UPS or
inverter
Proper operation by use of a UPS (uninterruptible
power supply) and an inverter is not guaranteed.
Do not use a UPS and an inverter.
*¹:For C941dn only

45530603TH Rev.2 1-9
Oki Data CONFIDENTIAL 1. CONFIGURATION
1.5 Interface specifications
1.5.1 USB interface specifications
1.5.1.1 USB interface overview
(1) Basic specifications
USB (Hi-Speed USB supported)
(2) Tr a n s m i s s i o n m o d e
Full speed (Max. 12 Mbps ± 0.25%)
High speed (Max. 480 Mbps ± 0.05%)
(3) Power control
Self-powered device
1.5.1.2 USB interface connectors and cables
(1) Connector
• Printer side: B-receptacle (female)
Upstream port
Product equivalent to UBB - 4R - D14C - 4D(LF)SN
Connector pin arrangement
2
34
1
• Cable side: B-plug (male)
(2) Cables
Length: USB 2.0 cables no more than five meters long (two meters or less
recommended)
(Shielded USB 2.0 cables shall be used.)
1.5.1.3 USB interface signals
Signal name Function
1 Vbus Power Supply (+5V)
2 D- For data transfer
3 D+ For data transfer
4 GND Signal ground
Shell Shield

45530603TH Rev.2 1-10
Oki Data CONFIDENTIAL 1. CONFIGURATION
1.5.2 Network interface specifications
1.5.2.1 Network interface overview
Basic specifications
Notwork protocol
TCP/IP: Network layer
ARP, IP, ICMP, IPv6, IPSec
Tr a n s p o r t l a y e r
TCP, UDP
Application layer
LPR, Port9100, FTP, HTTP, HTTPS, IPP, SNMPv1/v3, TELNET,
DHCP/BOOTP, DNS, DDNS, WINS, UPnP, Bonjour, SNTP, SMTP,
Windows Rally (WSD Print, LLTD)
NBT: SMB, NetBIOS over TCP
Ether Talk: ELAP, AARP, DDP, AEP, NBP, ZIP, RTMP, ATP, PAP
IEEE802.1X: EAP-TLS, PEAP
* This apparatus installs Oki Data Network Stack Version 1.0
acquiring IPv6 Ready Logo Phase-2 (IPv6 Core Protocols).
1.5.2.2 Connector and cable of network interface
(1) Connector
1000BASE-T / 100 BASE-TX / 10 BASE-T (automatically switched, not usable
simultaneously)
Connector pins arrangement
18
(2) Cable
Non-shield twisted-pair cable with RJ-45 connector (Category 5e equivalent or
more recommended)
1.5.2.3 Network interface signals
Pin No. Signal name Function
1 TRD+(0) Transmitting and receiving Data 0 (+)
2 TRD-(0) Transmitting and receiving Data 0 (-)
3 TRD+(1) Transmitting and receiving Data 1 (+)
4 TRD+(2) Transmitting and receiving Data 2 (+)
5 TRD-(2) Transmitting and receiving Data 2 (-)
6 TRD-(1) Transmitting and receiving Data 1 (-)
7 TRD+(3) Transmitting and receiving Data 3 (+)
8 TRD-(3) Transmitting and receiving Data 3 (-)

Oki Data CONFIDENTIAL
2. DESCRIPTION OF OPERATION
2.1 Electrophotographic process mechanism..................................2-2
2.2 Printing process.........................................................................2-5
2.3 Low-voltage Power Supply ......................................................2-17
2.4 Cover Opening and Closing Detection Switch.........................2-18
2.5 Initialization processing ...........................................................2-19

45530603TH Rev.2 2-2
Oki Data CONFIDENTIAL 2. DESCRIPTION OF OPERATION
(1) Electrophotographic process
The electrophotographic process is explained briefly below:
1. Charging
A voltage is applied to the Charging roller to electrically charge the surface of the
OPC drum.
2. Exposure
The LED head exposures light onto the charged OPC drum in accordance with
the image data. The electric charge of the exposured part of the OPC drum
surface decreases depending on the light, thus forming the electrostatic latent
image on the OPC drum surface.
3. Development
Charged toner are adsorbed to the electrostatic latent image of the OPC drum
by electrostatic power, and forms toner images on the OPC drum surface.
4. Tr a n s fe r
The intermediate transfer belt is arranged in contact with the OPC drum surface.
And the electric charges are charged to the belt by the first transfer roller that is
arranged at inside of the intermediate transfer belt. Therefore, the toner image is
transferred to the intermediate transfer belt. Then, the toner image is transferred
to the paper by the second transfer roller.
5. Drum cleaning
The drum cleaning blade removes toner remaining on the OPC drum after the
transfer.
6. Belt cleaning
The belt cleaning blade removes toner remaining on the belt.
7. Fusing
Heat and pressure are applied to the toner image on the paper for fusing.
2.1 Electrophotographic process mechanism
(2) Charging
The voltage is applied to the charging roller, which is arranged in contact with the
OPC drum surface, to charge the OPC drum surface.
-
-
-
--
-
Power
supply
unit
Charging roller
OPC drum
(3) Exposure
The light emitted from the LED head is exposured onto the charged surface of
the OPC drum. The charge of the exposured part of the OPC drum decreases
depending on the light, forming the electrostatic latent image on the OPC drum
surface.
-
-
-
--
---
-
Power
supply
unit
OPC drum
LED head
Charging roller

45530603TH Rev.2 2-3
Oki Data CONFIDENTIAL 2. DESCRIPTION OF OPERATION
(4) Development
Charged toner are adsorbed to the electrostatic latent image on the drum surface,
thereby the electrostatic latent image is converted to the toner image.
1. The sponge roller supplies the toner to the development roller.
-
-
-
--
---
-
-
-
-
Development roller
Sponge roller
OPC drum
Power supply unit
2. The electrostatic latent image at surface of the OPC drum is formed a visible
image by the toner.
(5) Tr a n s fe r
The intermediate transfer belt is arranged in contact with the OPC drum surface.
And the electric charges are charged to the belt by the first transfer roller that is
arranged at inside of the intermediate transfer belt. Therefore, the toner image is
transferred to the intermediate transfer belt. Then, the toner image is transferred to
the paper by the second transfer roller.
-
-
-
--
---
-
-
-
-
-
-
++
+
+
+
+++++++++++
Power
supply
unit
OPC drum
First transfer roller
intermediate transfer belt

45530603TH Rev.2 2-4
Oki Data CONFIDENTIAL 2. DESCRIPTION OF OPERATION
(6) Fusing
The toner image transferred on the paper is fused to the paper by heat and
pressure when the paper passes through between the portion of the fuser belt
(mainly comprised with the fuser roller, the pat and the fuser belt) and the pressure
roller in the fuser unit.
The fuser belt unit is heated by internal heater Assy. with specified wattage (e.g.
1200W in 230V environment). The fusing temperature is determined by the value
of the temperature that is the measurement of the thermistor. The thermistor is
arranged as it is contacted with the inside of the fuser belt.
There is also a thermostat for safety purposes. When the heater temperature rises
above a specific temperature, the thermostat opens and shuts down the power
supplied to the heater. The pressure roller is pressed against the fuser belt by press
springs those arranged both sides of the pressure roller.
Heater Assy
Thermostat
Fuser roller
Paper
Pressure roller
Thermistor
Thermistor
Pad
Fuser belt
(7) Drum cleaning
Unfixed toner remaining on the OPC drum is removed by the drum cleaning blade
and collected into the waste toner area of the toner cartridge.
(8) Belt cleaning
Ton e r r e ma i n i n g o n t he in t e r m e dia t e tra n s f e r b e lt is s c r a pe d o f f by the b e l t c le a n i n g
blade and collected into the waste toner box of the transfer belt unit.
Second transfer roller unit
Fuser unit
Timing roller
Belt drive roller
Paper
K-DrumC-Drum
Waste-Toner-Box
M-DrumY-Drum
Intermediate transfer belt
Spot color-
Drum
Belt cleaning blade
(9) Intermediate transfer roller cleaning
Toner remaining on the intermediate transfer roller is return to transfer belt by
electric field cleaning, and clean by belt cleaning structure.

45530603TH Rev.2 2-5
Oki Data CONFIDENTIAL 2. DESCRIPTION OF OPERATION
2.2 Printing process
The paper fed from Tray 1 or Tray 2, 3, 4 or 5 is fed by the paper feed roller, registration 1
roller, registration 2 roller and timing roller. When the paper is fed from the MPT, it is fed by
the MPT paper feed roller and the registration 2 roller.
Next, the paper fed to the TR2 roller is nipped by the TR2 BU roller arranged in the
intermediate transfer belt and TR2 roller.
Then, an unfused toner image which has been formed on the belt of the intermediate transfer
belt is transferred on the transported paper.
The unfused toner image is formed onto the belt sequentially through the each color
electrophotographic process as SP-Color(White or Clear toner (only 5-color model)), Y, M, C
and K.
Thereafter, the toner image is fused to the paper under heat and pressure as the paper
passed through the fuser unit.
After the toner image has been fused to the paper, the paper is ejected to a face-up stacker
or to a face-down stacker (which is depended on the preselected outputting method).
The above refers to the one-sided (Simplex) printing operation of the printer. Below, its
operation in bose-sided (Duplex) printing be explained.
When Duplex printing is set, the paper that has passed through the fuser unit following first
one-sided (to back-side) printing is transported into the Duplex unit by the separation of
the Duplex separator. After the paper is entered the paper reverse transportation path, the
paper is transported from there to the inside of the Duplex unit by the reversal motion of the
DUP reverse roller. Then, the paper which passed through the Duplex unit by the DUP 1, 2,
3, and DUP REG roller that is fed from the paper feed route of the Duplex. After the paper
is eventually transoprted to the same route that comes from the trays. From here on, for to
other one-side (front-side) printing, the same operation as that of one-sided print of paper fed
from the tray takes place.
When printing with 2 Pass, the paper is transported into the Duplex unit as in the Duplex
printing after the base printing. After the paper is entered the paper reverse transportation
path, the paper is transported to the 2 Pass transport path by the 2 Pass separator without
the reversal motion. After the paper is eventually transoprted to the route as same as in the
Duplex printing inside the Duplex unit. From here on, for to other one-side (front-side) printing,
the same operation as that of one-sided print of paper fed from the tray takes place.
Registration 2 roller
MPT paper feed rolle
r
Timing roller
TR2BU roller
FUSER roller
FD exit roller
Exit 3 roller
Exit 2 roller
FU exit roller
DUP reverse roller
2 Pass roller
2 Pass separator
Paper reversing
transportation path
2 Pass transport pat
h
DUP2 roller
DUP1 roller
TR2 roller
DUP 3 roller
Registration1 roller
Paper feed roller
Tray1
Tray2
Tray3
Tray4
Tray5
DUPREG roller
Intermediate transfer
belt