If the ‘counterfeiters’ would just call their merchandise ‘compatible’ and not use the other companies’ logos, but used their own, would they be legal?...............
“If the ‘counterfeiters’ would just call their merchandise ‘compatible’ and not use the other companies’ logos, but used their own, would they be legal?”
By default, yes.
They cannot duplicate the ink cartridges or other components that are protected by a patent. Sometimes this may even be a design patent, which is inexpensive and might deter competition.
Design patents are easy to circumvent legally, but may deter companies that are afraid of legal costs if they are sued and must defend their designs.
A lot of times big corporations game the system when it comes to intellectual property.
Of course, this fake stuff also infringes on trademarks and is defrauding consumers as well as.