For HP models, the ink is sprayed through dozens of fine holes in the nozzle (the gold plate at the bottom of the cartridge). The quality of output depends on the condition of this part, and if it is neglected for a long time or it is excessively used while the color is faint, the nozzle can dry up and be damaged, which directly affects the quality of output.
When you have faint colors, blank page output, or white lines, mostly the reason is dried up or damaged nozzle. When this happens, you must put it on a wet tissue for about one hour to induce recovery, and after confirming that the nozzle is wet with ink, perform “Cartridge Cleaning”.
[Caution] In order for the nozzle to be reused many times for a long time, it should be used regularly (at least once per month), and you must check the nozzle status and remained quantity for each color based on the output of “Cartridge Cleaning,” and refill the ink at the right time.