I have one of these really cheap brother HL-4040CN colour printers.
It works quite well for me
One of my customers also has the same printer, and has had it about the same amount of time that I have.
However, she hardly uses her printer (I probably print out 10 times as much as she does).
So when she called me to look as her printer (she said it was refusing to print), I assumed it would be a simple problem.
But once I had a good look, I could see that it was complaining about the waste toner cartridge being full.
My first thought was: what exactly is a waste toner cartridge?
It seems that as toner powder is arranged on a page, a small quantity doesn’t stay on the page, and ends up in a waste container.
Once this container is full, it must be replaced before printing can continue.
But… why did the customer printer fill the waste toner box before mine (and months later, mine is still not full).
Anyway, I first attempted to empty the waste toner box, but after making quite a mess, the printer still refused to print.
So I get a new cartridge, and everything was back to normal.
I then had a careful look at the old waste cartridge, and after dismantling it (and removing even more waste toner powder!), I started to notice that some of the surfaces had a sticky residue.
Ah, now that might explain the early “failure”… The customer might have had a fire, or maybe burnt some oil while cooking, and some of that sticky “smoke” probably made it into the printer.
Anyway, I eventually cleaned the box quite thoroughly, and its now waiting to be used in my own printer, once my own waste toner cartridge fills up.