If your printer leaves horizontal streaks (white lines)...
Your jets are probably clogged.
Perform the printer's head cleaning utility, 5 or more times if necessary. Refer to your printer's owner's manual to determine exact procedure

For HP cartridges and other cartridges with a "built in" print head.
After you have attempted a head cleaning routine (Refillimport rensevęske) we recommend using one of the primer pages below. Print several pages if neccessary to remove any ink or air that may be contaminating the print head.
Primer Pages