I have a similar black line (about 2inches in width, on the right side) on faxes sent from my Brother 4100e. I cleaned the scanner glass as suggested by you, but it continues to have the same problem on sent faxes. Received faxes are fine. Any additional suggestions

Either your machine's
primary corona wire for printing may be dirty, or the sending party's fax scanner may be dirty. Clean
your primary corona wire. I recommend placing the drum unit on a drop cloth or large disposable paper
to avoid spilling and scattering toner.
1. Clean the primary corona wire inside the drum unit by gently sliding the tab from right to left several times.
2. Return the tab and snap it into the Home position, (Caution: If the tab is not at the Home position, printed pages may have vertical stripes).
3. Reinstall the drum unit into the machine.
4. Close the front cover.
5. Plug in the power cord first, and then plug in the telephone cord.
or ask the sender to make a copy to see if the problem is with the sending machine.
Try receiving from another fax machine.
If the problem continues, call Brother Customer
Service at: 1-800-284-4329 (in USA) or 1-877-BROTHER (in Canada)

OR

You can also try these steps below

2 Reset the drum counter if you have already changed the drum recently. Open the device's front cover and press the button labeled "Clear," then close the cover and press the "1" button on the device's control panel.

3 Pull down on the top of the device's front cover. Slide the print cartridge assembly out of the inside of the printer and place it on a scratch piece of paper.

4 Depress the lever on the right side of the assembly and separate the toner cartridge from the drum assembly. Remove the new drum unit from its aluminum bag and snap the toner cartridge into it.

5 Place the print cartridge assembly back into the device and keep the front cover open. Press the "Clear" button, then press "1." Close the front cover once the device's screen reads "Accepted."



Regards,
Ron