ION toner cartridges go through a rigorous quality control process to ensure maximum results throughout the entire printing cycle. You may find that lower grade replacement toner cartridges may have similar output quality when printing the initial thousand pages, but will decrease in the sharpness lose its printing density of its printouts near the middle or the end. This is caused by uneven toner density distribution from the replacement toner cartridge. ION toner cartridges are carefully manufactured to ensure even printing density. This allows for a longer lifespan of your ION toner cartridge and consistency of providing you High Definition Printouts for your personal and office printing needs.