Printer ink cartridges are one of the most expensive items to buy for your home or office.

However, not everyone checks exactly how much of that ink is actually being used on their documents.

Consumer Reports found that a lot of printers use 50 percent or more of the ink on non-printing functions, such as cleaning the print heads. This occurs when the head moves back and forth after powering up the device. Consumer Reports says its research showed some models can waste up to $120 a year on
non-printing functions.

"We were surprised by the amount of ink some printers used," Paul Reynolds, the magazine's electronics editor, told USA Today.

Tests were conducted on a few dozen inkjet printers in the lab to determine exactly how much ink was being used in different models. These involved printing 30 pages of text or color over a three-week period. Testers found that most of the models used the majority of their ink to actually print documents.

"Our tests confirm that it's worth paying attention to how much ink is used for cleaning and maintenance and to make that part of your buying consideration," said Reynolds.

Consumer Reports say that HP Officejet Pro 8600 and Lexmark OfficeEdge Pro 4000 waste the most ink. On the other hand, Brother printers were found to waste the least amount of ink, more specifically the Brother DCP-J140W.

Irregular use of printers do cause a loss of ink. Some models tested by Consumer Reports let out only 20 to 30 percent of the ink to hit the pages. Manufacturers said the ink specified for their printers should be used for quality purposes.