The solution for an offline error of a printer is to check the proper connection of the printer.
Two options exist to turn off the offline mode.
If you choose the first option to change the offline state of the printer, then go to Control Panel and then ‘Printer and Faxes’ option on the Control Panel.
Double-click on the printer you want to change to online mode from the displayed window.
A pop-up window will open and you need to select ‘Uncheck Printer Offline‘ option from the menu bar.
Get more information to fix Windows 7 Printer Offline Error :http://printers.iyogi.com/help-support/windows-7-printer-offline.html
Hope this helps you.