I purchased a Brother® MFC-7840w multifunction laser printer some years ago and I have to say that it’s one of the better modern printers I’ve owned. Mac OS X software for it isn’t great (buggy), but it’s better than most of the others I’ve tried and the printer performs quite well. I’ve been recommending them to anyone who’s asked me (and I get asked quite a bit).
After finishing the small starter toner cartridge they supply with the printer I put in my first TN-360 “High Yield” toner cartridge which claims 3500 pages under “normal use”. I use this printer under what I’d consider normal conditions – mostly simple text documents.
Worked well but all of a sudden it just stopped printing with a message about the toner needed to be replaced. “That’s odd,” I thought to myself. “I’ve owned a lot of laser printers over the last 22+/- years and they’ve always started gradually printing more and more faintly when the toner was running out and I’ve never had a printer just refuse to print until I changed the toner cartridge before! Seems pretty heavy handed. Then I calculated the number of pages it had printed (2120) and had an uncomfortable thought: “If they just stop and refuse to print and the printouts were looking just fine right up until that point, how do I know it’s really out of toner?”
I didn’t get my money’s worth and the forced toner replacement was feeling heavy handed and annoying. So I wondered, “how do they decide to put up that alert anyway?” Pulled the toner cartridge out and started examining it looking for electrical contacts (sensors inside?) or some other mechanism. I found this:
Note the arrow. It’s pointing to a clear plastic “window” on the right side of the toner cartridge when you’re looking at the top from the front where the handle is. It appeared like it might give the printer an optical view into the insides of the toner cartridge. “Ah HA!” I thought. Small piece of Gorilla tape (sticks much better than electrical tape) later and I had this:
Put it back in and time for a test…
Printer prints PERFECTLY… We are being ripped off by Brother and that really sucks.
This fixed worked for another 1001 perfect printouts and then it stopped again…
“DANG IT! The printouts were still looking *fine*!”
Take the toner out to put in the replacement and notice something on the side when you’re looking at the bottom:
There’s Another Sensor Window! (With Gorilla tape on it in this image). Here’s a close-up:
This piece of tape added and, sure enough, working FINE again… ARG FARG SNARG – BROTHER! I want to like you but this is robbery! AND it’s bad for the environment which makes it even more offensive. Rarely do I want to call for a class action lawsuit, but this situation was definitely making me feel that way…
How many perfectly fine beautiful printouts did I get after blocking the second window? I can’t tell you yet because it’s still going strong 200 sheets later. 
So, if you want to get the full life out of your Brother TN-360 High Yield printer cartridge you may want to pick up a roll of Gorilla Tape and prepare to “fix” the cartridge. Be careful to make sure the tape is stuck on there will because a loose piece of tape being drawn through your printer will probably do bad things to it (Follow these instructions at your own risk!).
Please add a comment if you try this with a different printer model and it works for that one also; likewise for other Brother toner cartridges. Thanks!
Cheers.
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