Can not print in an Epson Stylus 640

I use gs -sDevice=stcolor -sOutputFile=/dev/lp0 -r<720x720> myfile.ps and I only get white papers but with gs -sDevice=stcolor -sOutputFile=/dev/lp0 -r<360x360> myfile.ps no problem. All this happens went I actialized to slink. Before this all woked OK What's the problem?. Has it any solution? Than

Can not print in an Epson Stylus

I use gs -sDevice=stcolor -sOutputFile=/dev/lp0 -r<720x720> myfile.ps and I only get white papers but with gs -sDevice=stcolor -sOutputFile=/dev/lp0 -r<360x360> myfile.ps no problem. All this happens went I actialized to slink. Before this all woked OK What's the problem?. Has it any solution? Than