PROBLEM
Horizontal white lines in your print out are the most common and somewhat aggravating to say the least. The main cause of this is a blocked printhead which is either in the printer itself as are the Epson/most Canons/Brother/ Xerox etc. Hewlett Packard / Lexmark /Olivetti / some Canons / Xerox etc have the printhead as part of the cartridge.
VERY IMPORTANT- DON'T LET THE PRINTHEAD DRY OUT!
Whether you are using OEM's or compatible cartridges it is very important not to let the cartridges run completely dry of ink as this causes the printhead nozzles to dry out (they are finer than a hair on your head) If this should happen with a printer with the printhead in the machine you will have to do possibly multiple head cleaning operations as per your printers software. This is both time consuming and consumes copious ammounts of ink during the cleaning cycles but it should produce the required results.
Should you experience the problem with an ink cartridge that has the printhead built into it then there are limited functions you can try. The black cartridge is the easiest to get going again either by doing a cleaning cycle via your printers software or for a quick solution by putting boiling water into a clean small dish / saucer etc and immerse just the tip of the cartridge into the water and hold it there for approx 60 seconds - take out and blot the head with a piece of kitchen-roll.
The tri-colour cartridge is a differnet kettle of fish due to its intricate manufacture and would only suggest you try to unblock by operating a cleaning cycle via the printers software - perhaps a couple of times at the most - if this fails to unblock then I'm afraid it's a new cartridge needed.
