Every good printer is known to have some extra use for the different documents and files that need to be printed. For inkjets, this includes the ability to print in black and white, combined with a quick and simplistic way to print out a number of documents.  However, there are several that have run into the problem of the ink cartridges not having the ability to print because of low toner. If you want to make sure that your HP printer continues to print without this problem, then getting an HP21 inkjet cartridge refill is the simple solution. This helps you to keep printing while providing you with a lower cost by using a refill instead of a new cartridge.  With this, you can continue to get the right results and looks for your documents.