Customer Rating: 
Summary: A Trick to extending yield 33-50%
Comment: This cartridge will disable your printer once it (the cartridge) tells your printer it's empty. The cartridge has a window that is closed (blocked) by toner. This window runs through the cartridge from one side to the other. When the toner is full, the window is blocked, when the toner is seemingly empty, a laser is able to shine through the cartridge one side to the other thus signaling to the printer to shut down for cartridge replacement. I have found that when you obstruct this window with a simple piece of masking tape, you will have at least 33-50% more toner left. I'll leave any manufacturer motive speculation up to you.
Customer Rating:
Summary: Brother Toner -- boring, but good!
Comment: This toner works great with the Brother All-In-One I have. The reason I wrote this is to warn everyone to NOT use off brand toner. I have had a HUGE mess due to using a fairly well known replacement toner. When I changed back to Brother, after time for the old toner to get out of the system, everything got OK. So, yes, the do have us married to their toner!
Customer Rating:
Summary: Very low capacity
Comment: This supposed high-capacity toner cartridge did not even print 2,000 pages with very little type and no art on them. Considering the cost I am VERY unhappy! I print maybe 600 - 700 invoices a month. This cartridge should have lasted a year and did not even last 3 months. At this rate it is more expensive than the ink jet printer I replaced. Buyer beware!
Customer Rating:
Summary: Good yield toner cartridge
Comment: I thought these toner cartridges were awful and overpriced. our office was going through these things like Little Debbie Swiss Roll Snack Cakes. That was until I started actually researching toner cartridges. At the current price of this cartridge, the yield is $.01 a page. Compared to the Ricoh business class printers with their toner cartridge yield of $.014, this is cheaper, and the printer is much less expensive.
These cartridges are also cheaper than the regular Brother TN550 (3,500 YLD) Standard Yield Toner Cartridge which currently have a yield of $.015 per page.
Customer Rating:
Summary: Brother TN580 TONER CARTRIDGE
Comment: This item is a new, never used cartridge and works perfect. It was less than 1/2 price of a new standard cartridge. May you never quit selling them and may I never quit buying them. Keep up the good work!!
Summary: A Trick to extending yield 33-50%
Comment: This cartridge will disable your printer once it (the cartridge) tells your printer it's empty. The cartridge has a window that is closed (blocked) by toner. This window runs through the cartridge from one side to the other. When the toner is full, the window is blocked, when the toner is seemingly empty, a laser is able to shine through the cartridge one side to the other thus signaling to the printer to shut down for cartridge replacement. I have found that when you obstruct this window with a simple piece of masking tape, you will have at least 33-50% more toner left. I'll leave any manufacturer motive speculation up to you.
Customer Rating:
Summary: Brother Toner -- boring, but good!
Comment: This toner works great with the Brother All-In-One I have. The reason I wrote this is to warn everyone to NOT use off brand toner. I have had a HUGE mess due to using a fairly well known replacement toner. When I changed back to Brother, after time for the old toner to get out of the system, everything got OK. So, yes, the do have us married to their toner!
Customer Rating:
Summary: Very low capacity
Comment: This supposed high-capacity toner cartridge did not even print 2,000 pages with very little type and no art on them. Considering the cost I am VERY unhappy! I print maybe 600 - 700 invoices a month. This cartridge should have lasted a year and did not even last 3 months. At this rate it is more expensive than the ink jet printer I replaced. Buyer beware!
Customer Rating:
Summary: Good yield toner cartridge
Comment: I thought these toner cartridges were awful and overpriced. our office was going through these things like Little Debbie Swiss Roll Snack Cakes. That was until I started actually researching toner cartridges. At the current price of this cartridge, the yield is $.01 a page. Compared to the Ricoh business class printers with their toner cartridge yield of $.014, this is cheaper, and the printer is much less expensive.
These cartridges are also cheaper than the regular Brother TN550 (3,500 YLD) Standard Yield Toner Cartridge which currently have a yield of $.015 per page.
Customer Rating:
Summary: Brother TN580 TONER CARTRIDGE
Comment: This item is a new, never used cartridge and works perfect. It was less than 1/2 price of a new standard cartridge. May you never quit selling them and may I never quit buying them. Keep up the good work!!