Which best type ink to printer directly to copper

Hello folks,

I intend use this printer (Lexmark X1150) - http://support.lexmark.com/index?locale=EN&page=product&userlocale=EN_US&productCode=LEXMARK_X1150 to do this:

I can adapted this device to printer directly on pcb, but I having problems with ink on cooper. The ink don't dry on cooper. Even after I putted the pcb inside electric oven with temperature to prowl 150 degrees.

What type ink I should I use on this situation?
Thanks