This article pertains to any
PRINT QUALITY ISSUES with
toner cartridges after they have been refilled:
Although almost all customers are satisfied with the quality of their cartridge after they refill it, the print quality depends on the condition of the cartridge and the level of usage / wear and tear of the cartridge. Quality is always going to be best when you refill an Original brand cartridge or a professionally remanufactured cartridge (that has gone through only 1 life cycle). Refilling a non-original brand cartridge (such as a compatible brand, or a cartridge which has been refilled multiple timnes) will have a much higher rate of cartridge wear and tear, and therefore lower quality prints. For these reasons we also do not recommend more than 1-2 refills on the same cartridge. Please note that even original brand cartridges can wear out early, but they will perform on average much better than non-original or multiple-refilled cartridges. You can see more info about this
here.