IT IS A BRAND NEW TONER AND WHEN IT PRINTS IT LEAVES SOME INK SPOTS ON THE LEFT SIDE OF THE PAGE

If you are using a generic toner, replace it with cartridge from Brother. Many of these are caused by using a refilled cartridge or a generic cartridge. Use a cleaning sheet and run it though a couple of times, if this does not clear it up you need a new cartridge.

Step 1:

Print out about 10 blank (all white) sheets and see if the spots clean off.

Step 2:

Check to see if the toner is Dell type brand, if not try installing Dell brand and run 10 blank copies then run color test print using menu key.
Press menu, press arrow down key till 'print reports' is displayed, Press 'check key' then press down key till 'color test print' Press check key to print color copy.

Could be toner build-up on the fuser sleeve. Pull out the fuser and check the rollers for spots.
Try running cleaning pages before replacing fuser.

Did you remove the strip that the printers ship with? If the pull tab is still in then there is typically enough toner to print a few pages and then it fades out. Remove cartridge and check on left and right hand sides for a plastic loop usually orange. The instructions would have been in the box.

Here is my solution, hope it will solve your problem.

From your post, I believe your CLP-350N printer has enough black toner. The black cartridge is on the far right side of the printer, so the black toner is harder to go to left side of the roller than right side. Everytime we start the printer, it will move some toner of each color to the roller before it shows ready to print.

Because we always use B&W printing when we start the printer, but less Color printing. The result is there are always enough toner on the 3 color rollers, but the black toner is lean on the black roller. When this gets worse, the left side of the black roller may hardly get any toner at all -- so it only print black on the right side fo paper.

Step by step solution
(CAUTION: Never loss balance while tilting printer! You may drop and damage your printer! Hold the printer firmly all the time! Ask someone to help you if needed!)

Here, front of the printer is where you can access the cartridge, back of the printer is where you connect the power cord and USB cable, left is your left, right is your right.

1.Lift the front to keep the printer tilt to its back at about 45 degree
2.Power on printer while it's tilted back, wait untill green light is on
3.Open the front door, red light will be on, then close the door, printer will start up again,wait untill green light is on
4.Repeat step 3 once again, then put the printer back to level position
5.Lift the right to keep the printer tilt to its left at about 45 degree
6.Open the front door, red light will be on, then close the door, printer will start up again, wait untill green light is on
7.Repeat step 6 once again, then put the printer back to level position
8.Print some test page to see if there is any improvement of black print quality.(Hold the printer button for 3-5 seconds, it will print the test page.)

You may try several times and print several pages each time before you finally cure the problem.

Good luck! And do it safely!

please you used the colour printer ? if yes then your check the csrtridge a refeling the towner and service the cartridge and service in printer and aply the print is ok.

Use follow these cleaning steps for your printer:

1. Open the front cover of the printer and remove the drum/toner unit.
2. Gently wipe the scanner window with a soft dry cloth. The scanner
window is located on the roof of the inside of the printer.
3. On the top of the drum unit, locate the blue tab on the left side.
Slide it back and forth across the drum about 30 times.
4. Remove the toner cartridge (TN430 or TN460) from the drum unit
(DR400). To remove the toner from the drum: hold down the blue lever on the right side of the drum (DR400) and lift the toner (TN430 or TN460) off of the drum unit.
5. Inside the drum unit (DR400) there is a green roller. Wipe the green
drum roller with a dry tissue (i.e. Kleenex). You may turn this roller
by moving the gears on the far left side.
6. If the pages area gray pages or have gray vertical lines, install a
brand new toner cartridge. If pages have dots, spots, smudges or
horizontal lines, install a brand new drum unit.
OR
If you are still experiencing gray pages or gray vertical lines,
please install a brand new toner cartridge (TN430 or TN460).

Brother strongly recommends that customers do not use generic drum unitsand/or toner cartridges, or refill their Brother toner cartridge. Each Brother laser printer is designed to work at pre-set temperatures that are matched exactly to each of our individual toner formulations. Each individual component is designed to work with the other to ensure quality and reliability. Using non-Brother supplies may affect the hardware performance, print quality and machine reliability.
The Brotherlimited warranty does not apply to any problem that is caused by the useof unauthorized third party drum units, toner cartridges or toner.

If I have helped please rate my post...I will always do my best to help

INSPECT THE DOCUMENT READER GLASS THIS SOMETIMES GETS WHITE OUT OR OTHER JUNK ON ON THE LENS AND LEAVES A VOID AREA.

Are you using off-brand ink? My Office Depot brand toner never prints correctly. When I replace it with Brother brand, presto!

I have a SCX-4100 Samsung, replaced the tonger cartridge, it was working fine for a few hundred sheets of printing, but after that, the left side of the page was printed very light, faded.
If I run the "Clean Drum", it will print a litter better, but still faded.
What can I do to correct this problem?
Thank you
TT