If you have a compatible / remanufactured HP 920 / HP 940 ink cartridge and it is not printing well (colors are not coming out well, lines on the page etc), you may need to check that the "breather holes" on those cartridges are free and clear of any plastic or glue - and are wide open to accept incoming air from the environment.
Sometimes when the sealing tape that covers these breather holes is pulled away, it leaves some residue glue. You can ensure that the breather holes are wide open by piercing through this breather hole with a money clip tip, or a pen, to ensure that it is wide open.
See attached for the location of the breather hole on these cartridges.
Please click here to download attachment link
Please click here to download attachment link