1) A “half test” is to do a printing test and when the page is half way through you open the cover.

2) It might take a few tries to get the correct timing. What you are looking for is to see defects on the image and know if it happens before or after the page passes through the fuser.

3) The fuser melts the toner to the page. If the defect is after the fuser then you need to replace the fuser and you can do so by getting a fuser maintenance kit. If the defect is before you know that your fuser is not the problem and that it could be the next two options.

4) Transfer Belt issue or toner cartridge.

5) To narrow it even more you should clean your transfer belt being careful not to touch it, because it is very sensitive to any fingerprints etc. Use a dry lint free cloth to clean gently.

6) So if problem persist the last option then it is low or empty toner cartridge and that is only resolved by changing the cartridge. No problem there because you can find the lowest prices toners for your HP 200n at Inkjetsuperstore.com