Brother MFC 9840CDW User Manual

Troubleshooting and routine maintenance
159
C
Cleaning the drum unitC
If you have print quality problems caused by 
repeating marks on the page, clean the drum 
unit as follows.
aPress the front cover release button and 
then open the front cover.
 
bClose the front cover of the machine. 
The machine starts warming up, wait 
until it finishes warming up before going 
on to stepc.
cPull out the MP tray (1) and unfold the 
MP tray support flap (2).
 
dPut a blank sheet of A4 or Letter sized 
paper in the...

160
gThe following message appears on the 
LCD when the machine has finished 
cleaning. 
 
DRUM CLEANING
COMPLETED
hPress Stop/Exit so that the machine 
returns to the Ready state.
iTry to print again. If this problem still 
remains, repeat stepsc to h several 
times. 
If the problem still remains after 
repeating stepc to h several times, go 
to stepj.
jTurn off the machine’s power switch. 
Unplug the telephone line cord first, and 
then unplug the power cord from the 
electrical socket.
kPress the...

Troubleshooting and routine maintenance
161
C
CAUTION 
We recommend that you place the drum 
unit and toner cartridges separately on a 
clean, flat surface with a piece of 
disposable paper underneath them in case 
you accidentally spill or scatter toner.
 
 
 
 
Handle the toner cartridge carefully. If toner 
scatters on your hands or clothes, wipe or 
wash it off with cold water at once.
 
mRelease the grey lock lever (1) that is on 
the left side of the machine. Lift the front 
of the drum unit and...

162
nUsing their coloured handles to lift them 
out, remove all four toner cartridges 
from the drum unit.
 
CAUTION 
To prevent damage to the machine from 
static electricity, DO NOT touch the 
electrodes shown in the illustration.
 
 
 
Handle the toner cartridges carefully. If 
toner scatters on your hands or clothes, 
wipe or wash it off with cold water at once.
 
 
To avoid print quality problems, DO NOT 
touch the shaded parts shown in the 
illustrations.
 
 
 
 
 

Troubleshooting and routine maintenance
163
C
oWhile holding both hands, turn the drum 
unit upside down and place on a piece of 
disposable paper or cloth. Make sure 
that the drum unit gears (1) are on your 
left hand side.
 
pSee the print sample to identify the 
colour causing the problem. The colour 
of the spots or toner stain is the colour of 
the drum you should clean. For 
example, if the spots are cyan, you 
should clean the drum for cyan. Put the 
print sample in front of the drum, and the...

164
sTurn the drum unit gear toward you by 
hand to return it to the home position. 
The home position of each drum can be 
identified by matching the number on 
the drum unit gear to the same number 
on the side of the drum unit as shown in 
the illustration. Make sure that the 
number on each of the four drum unit 
gears matches the corresponding 
number on the side of the drum unit.
 
tHolding the toner cartridges by their 
coloured handles, insert them one by 
one back into the drum unit as shown....

Troubleshooting and routine maintenance
165
C
uPut the drum unit back in the machine as 
follows.
1Make sure that the grey lock 
lever (1) is in the up position and 
put the drum unit in the machine. 
Push down the grey lock lever (1).
 
Note
When you put the drum unit in the 
machine, match the green guides (1) of 
the drum unit handle to the green 
arrows (2) on both sides of the machine.
 
 
1
1
2
1
2
1
 

166
2Push the drum unit in until it stops. 
vClose the front cover of the machine. 
wPlug the machine’s power cord back into 
the AC electrical socket first, and 
reconnect all cables.
Turn on the machine’s power switch.
 

Troubleshooting and routine maintenance
167
C
Replacing the consumable itemsC
When the time comes to replace consumable items, the following messages will appear on the 
LCD.
The machine will stop printing when the following maintenance messages appear on the LCD.
1The toner cartridge colour which is used up is shown in the message.
2At 5% print coverage (A4 or Letter size). The actual number of printed pages will vary depending on the print jobs and 
paper you use.
3At 5% print coverage for CMYK each...

168
The following are maintenance messages that appear alternately with the normal message on the 
upper row of the LCD when the machine is in the Ready mode. These messages advise you that 
you will need to replace each of the consumable items as soon as possible, since the consumable 
item’s end of life has been reached. The machine will continue printing when any of these 
messages appear on the LCD.
1When printing on Letter or A4 size paper. The actual number of printed pages will vary depending on...