Please post the outputs of 'lpstat -t' on the server and a client.
scheduler is running system default destination: T640 device for PDF: cups-pdf:/ device for T640: socket://192.168.1.220:9100 PDF accepting requests since Mon 09 May 2016 07:25:03 PM CEST T640 accepting requests since Tue 10 May 2016 01:00:30 PM CEST printer PDF is idle. enabled since Mon 09 May 2016 07:25:03 PM CEST printer T640 is idle. enabled since Tue 10 May 2016 01:00:30 PM CEST Pol