If you have cleaned the print head and changed the ink cartridge and the print quality of the test sample is still not satisfactory you may need to replace the print head. Contact your machine supplier for advice.
Open the printer cover.
Pull the blue latch all the way forward until it stops.
Lift the blue print head handle up to a vertical position and then lift the print head straight up and out.
Remove the new print head from its packaging. Shake the print head three times.
Make sure the blue handle is down.
Push the blue latch back until it stops.