Now you may be wondering why are there so many lines on this page, as it turns out all these lines produce a pattern that has been saved in the printer’s memory, and helps identify when the ink cartridges are fine. This picture shows what this particular test sheet looks like, remember this is only an example and that test sheets can vary depending on your printer’s brand or model. This test sheet will let you know if the ink cartridge has run out or is printing blurry, letting you see how the ink exits the cartridge itself. The device will print this test sheet every time you remove one of its ink cartridges and put it back inside, regardless of it being filled with ink or not. Now why does this happen when I turn to refill my ink cartridges or when you turn your printer on? This issue occurs when you take out an ink cartridge from the printer since the printer has a way of knowing a cartridge has been removed or installed in it. This is what Hewlett-Packard has developed to find out when ink cartridges have run out and to stop the printer from printing any more sheets.

Printer only prints test page