How to Keep a Printer From Switching to Offline

Open the Start menu and click Control Panel.
Double-click the Printers and Faxes or Printers and Devices icon.
Right-click the icon for the printer that keeps switching to offline mode and choose Properties from the contextual menu that appears.
Go to the Ports tab at the top of the pop-up window.
Click the button labeled 'Add Port.'
Choose Standard TCP/IP Port from the drop-down list and click 'New Port.'
Enter the printer's IP address and click 'Next' and 'Finish.' The printer will automatically go online and will stop switching to offline mode.