They haven’t invented a printer that does not have any problem yet

If you can accept the fact that printers will have problems no matter if you have the best and the most modern, that it would be easier to figure out your current problem. Printers can be quite unpredictable as all modern tools. Working best for a moment then having problems the next.

There are many explanations to why printers turn out the way they do as you use them. There are the cartridges, the inks themselves and maybe some internal part that needs some maintenance or something. I think it is best to give it back from where you brought it and let them figure the problem. It is like they are the experts on these things so let them figure out the solution!

Seriously though, try going over their site and see it they offer maintenance tips. Or you could try writing your queries there. Besides being the inventors of these printers, maybe they would know how to fix your problem. If the problem persists, try the next best thing; buy a new printer!