Toner is "tricky".
I sell generic toner for many brands. About 80% of the time it works great and saves the customer about 50% (You may have noticed, I am CHEAP!!)
The other 20% of the time it gives crappy quality or blank areas, etc. Sometimes one machine will have different results with two cartridges that are "Identical".
I have an "ace in the hole" since my technician can FIX any problems that develop.
If the copier/printer is a cheapy (under $300), you've got little to lose. IF it is over that, buy your replacement from someone who will stand behind the results. They won't be the absolute cheapest, but if I can't tell which ones will work, I seriously DOUBT that YOU can!!!
The guy selling them MAY have to perform service on your machine, if the toner screws it up. This CAN be a revenue source for unscrupulous copier dealers (I am told such people exist).
Technically, there is one other consideration. Usually a refillable cartridge will incorporate the toner and a photoconductor (often called a "drum") as well as developer in some systems. The photoconductor also has a life, as will the developer (if it is used, some units omit this, they are called mono-component). After a couple toner refills, these other components are the real problem, so adding toner will NOT give you good copy quality.
Sorry, I'd love to give you a "black-and-white" answer, but the question is full of gray, and so will your copy be, if you goof!!!
Good luck, hope this helped.
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