H, francescom,
HP does not have a driver for the J4580. It seems from the error you are seeing that you may not be able to fax from the computer. You can however, print what you want to fax, and then fax directly from the computer.
The alternate option is to contact HP. Hp might be able to offer you a discount on a newer model, one that has compatible software and drivers for 10.9.
The number to call HP is 1-800-474-6836 for Canada and US , or you can Contact HP Worldwide.