It is vital that no particles reach the nozzles in the print head, otherwise a blockage can occur. Inkjet nozzles typically measure 20 microns, so inkjet ink has to be clean from imperfections. That is why Premium Inks brand ink is filtered to 2 microns or less! Our inks are filtered several times during manufacture, making sure that there are no larger particles or contaminants remaining in the final formulation. In addition care is taken with the ink bottles to ensure that they are also free from dust, dirt, and fragments from manufacture.
Many of our Epson refillable cartridges include a 2 micron filter as extra protection against a print head nozzle blockage. Our Canon refillable cartridges have an internal sponge which prevents particles from reaching the nozzle.