How to Clean Streaking HP600 Series Printers:

1.  Get a damp paper towel.

2.  Remove the cartridges from the printer

3.  Below the cartridge carrier is a flap that you can press down (see picture).  You have to hold this down to get to the "feet" in the next step.

4.  Use the paper towel to clear the lint and extra ink from the bottom of the three "feet" on the cartridge carrier (see picture).  It is the lint that is causing the streaking so you might need to use your fingernails through the towel to scrape all of it off.