Brother MFC 9420CN User Manual

Chapter C
C - 16
Improving the print quality
If you are having problems with print quality, please do a test print first (Menu/Set, 4, 2, 3).
If the problem appears on the printout, then match it to one of the examples below and follow the 
recommendation. If the problem does not appear on the test print, please check driver settings 
and the interface cables as the problem may not lie with the machine.
Examples of poor print qualityRecommendation
White lines or bands or ribbing 
across the page■Check...

Troubleshooting and routine maintenance
C - 17
C
Colored streaks or bands down the 
page■Identify the color and replace that toner cartridge. (See Replacing a toner 
cartridge on page C-29.)
■Replace the OPC belt cartridge. (See Replacing the OPC belt cartridge 
(OP-4CL) on page C-33.)
Colored lines across the page■Clean the registration roller, the paper pick-up roller, the transfer roller guide 
and the exit roller. (See Cleaning to prevent paper jams on page C-22.)
■If the problem continues, identify...

Chapter C
C - 18
Toner scatter or toner stain■Identify the color causing the problem and replace that toner cartridge. 
(See Replacing a toner cartridge on page C-29.)
■Replace the OPC belt cartridge. (See Replacing the OPC belt cartridge 
(OP-4CL) on page C-33.)
The color of your printouts is not 
what you expected■Check that the toner cartridges are installed properly.
■Check that the toner cartridges are not empty. (See Toner empty message on 
page C-29.)
■Perform the calibration. (Menu/Set, 4, 4)...

Troubleshooting and routine maintenance
C - 19
C
Missing image at edge■Check that the toner cartridges are installed properly.
■Check that the OPC belt cartridge is installed properly.
■Identify the color causing the problem and replace the toner cartridge. 
(See Replacing a toner cartridge on page C-29.)
■Replace the OPC belt cartridge. (See Replacing the OPC belt cartridge 
(OP-4CL) on page C-33.)
Wrinkle■Change to a recommended type of paper, and then check that the problem is 
solved. (See...

Chapter C
C - 20
Setting Dial Tone Detection
Setting the dial tone to Detection will 
shorten the dial tone detect pause.
1Press Menu/Set, 0, 5.
2Press ▲ or ▼ to select Detection or 
No Detection.
Press Menu/Set.
3Press Stop/Exit.
Compatibility
If you are having difficulty sending or 
receiving a fax due to possible interference 
on the phone line, we recommend that you 
adjust the Equalization for compatibility to 
reduce the modem speed for fax operations.
1Press Menu/Set, 2, 0, 1.
2Press ▲ or ▼ to...

Troubleshooting and routine maintenance
C - 21
C Cleaning the outside of the 
machine
Clean the outside of the machine as 
follows:
1Pull the paper tray completely out of the 
machine.
2Wipe the outside of the machine with a 
soft cloth to remove dust.
3Remove anything that is stuck inside the 
paper tray.
4Wipe the inside and the outside of the 
paper tray with a soft cloth to remove 
dust.
5Re-load the paper and put the paper tray 
firmly back in the machine.
CAUTION
■Use neutral detergents. Cleaning...

Chapter C
C - 22
Cleaning the scanner glass
Lift the document cover. Clean the scanner 
glass and white plastic above it with isopropyl 
alcohol on a soft lint-free cloth.
In the ADF unit, clean the white plastic bar 
and the scanner glass strip under it with 
isopropyl alcohol on a lint-free cloth.
Cleaning to prevent paper 
jams
When you clean the inside of the machine, 
pay attention to the following:
White Plastic
Scanner 
glass
Document 
Cover
Glass Strip
White 
Plastic Bar
WARNING
■The fusing unit...

Troubleshooting and routine maintenance
C - 23
C
1Turn off the machine’s power switch. 
Unplug the telephone line cord first, and 
then unplug the power cord from the AC 
power outlet. Open the back cover of the 
machine.
2Clean the registration roller and the 
paper pick-up roller with a dry soft, 
lint-free cloth to prevent paper jams.
3Clean the transfer roller unit and the 
transfer roller guide with a dry soft, 
lint-free cloth to prevent paper jams.
WARNING
■Be careful you do not break the...

Chapter C
C - 24
4Clean the exit roller. This will help to 
prevent paper jams at the paper exit and 
dirt from appearing on your printouts.
5Close the back cover.
6Plug the machine’s power cord back into 
the AC power outlet first, and then plug 
in the telephone line cord. Turn on the 
machine’s power switch.
Cleaning the laser glass
1Turn off the machine’s power switch. 
Unplug the telephone line cord first, and 
then unplug the power cord from the AC 
power outlet.
2Open the scanner unit.
3Open the...

Troubleshooting and routine maintenance
C - 25
C
6Place the OPC belt cartridge on a flat 
surface and cover the shiny green OPC 
belt with a piece of paper to prevent 
exposing it to light.
7Open the front cover of the machine.
8Take all the toner cartridges out of the 
machine.
9Clean the surface of the laser unit with a 
dry soft, lint-free cloth.
0Open the laser glass cover.
AClean the surface of the laser glass with 
a dry soft, lint-free cloth.
BClose the laser glass cover.
CPut all the toner...