Brother MFC-9420CN Service Manual

Confidential
9-48
I-24 Uneven Density (Right & Left)
Phenomenon
The optical density is different between the right and left side of the printed image.
Main Causes
(1) The amount of toner in the toner cartridge PU is short.
(2) The retract operation of the toner cartridge PU is not properly done.
(3) The belt of the toner cartridge PU is deformed.
(4) The belt of the transfer unit is deformed.
(5) The transfer roller ASSY PU is not properly installed.
(6) The back cover ASSY PU is deformed.
(7) The back cover ASSY PU is not locked sufficiently
(8) The dustproof glass of laser ASSY PU is stained.
Fig. 9-24
Countermeasures
(1) Replace the toner cartridge PU.
(2) Check the toner retract clutch PU.
(3) Replace the belt cartridge PU.
(4) Confirm the proper installation of the transfer roller ASSY PU.
(5) Replace the transfer roller ASSY PU.
(6) Ensure to lock the back cover ASSY PU.
(7) Replace the back cover ASSY PU.
(8) Clean the laser ASSY PU.
(9) Replace the laser ASSY PU.
Toner cartridge PU
(K, Y, M, C)
Laser ASSY PU
Belt cartridge PU
Transfer unit PU
Transfer belt
Back cover ASSY PU

Brother MFC-9420CN Specifications

General

Print technology	Laser
Maximum resolution	1200 x 2400 DPI
Economical printing	Yes
Print speed (black, normal quality, A4/US Letter)	31 ppm
Print speed (color, normal quality, A4/US Letter)	8 ppm
Digital sender	No
Number of print cartridges	4
Scanner type	Flatbed scanner
Scanner features	Scan to: e-mail, image, OCR, file
Copier resize	25 - 400 %
Maximum copy resolution	600 x 600 DPI
Maximum number of copies	99 copies
Copy speed (black, normal quality, A4)	31 cpm
Copy speed (color, normal quality, A4)	8 cpm
Faxing	Color faxing
Fax memory	500 pages
Modem speed	33.6 Kbit/s
Fax speed dialing (max numbers)	200
Total input capacity	750 sheets
Maximum input capacity	250 sheets
Auto document feeder (ADF) input capacity	35 sheets
Maximum internal memory	576 MB
Bundled software	ScanSoft PaperPort Presto! PageManager
I/O ports	IEEE-1284 USB 2.0
Dimensions (WxDxH)	483.5 x 514 x 530 mm
Printer management	BRAdmin Professional, MIB-II
Networking features	10Base-T/100Base-TX
All-in-one functions	Fax, Scan
Color all-in-one functions	copy, fax, print, scan
Compatible operating systems	Windows 98(SE)/ Me/ NT WorkStation 4.0/ 2000 Professional/ XP Mac OS 9.1 - 9.2, Mac OS X 10.2.4+
Sustainability certificates	ENERGY STAR
Power consumption (standby)	85 W
Power consumption (PowerSave)	16 W
Power consumption (average operating)	1090 W
Operating temperature (T-T)	10 - 32 °C
Operating relative humidity (H-H)	20 - 80 %
Market positioning	Business