Mi Michel,
I cannot access any of the VideoJet manuals through their web site without registration so I cannot get the details of the communications interface.
If this interface is truly bi-directional, where the data packets are sent to the printer and it sends a response back that needs to be handled I think you will need a custom solution. We have don bi-directional Socket communications from a 3rd party product KepServerEX. this is an OPC Server that PCo (and MII throuhg PCo) can communication with, and it has a UCON (User CONfiguratble) driver that can send and receive data streams over a socket connection. It may be possible to utilize this product to drive the printer communicatons, but without access to the communications protocol I cannot say for sure.
Regards, Steve