Does this by any chance happen when the device is not being used an goes into sleep mode? And that it won't wake up from sleep mode anymore?
Enter the IP address of the printer in the Address field, and then press [Enter] on the keyboard. The CentreWare Internet Services window will be displayed.
Click on the [Properties] tab
Enter the username and password in the fields provided, and then click on the [Login] button.
Click on the [General Setup] link to expand the list of options.
Click on the [Sleep Mode Settings] link. The Sleep Mode Settings window will be displayed.
Uncheck the [Suspend Network Controller Activity When in Sleep Mode] and [Apply]
Device should still go in to sleep now, only with a activated nw controller which allowes it to wake up.