Now click on 'about' button. And the following screen appears.
The tricky part comes now. Hold the 'Shift' and 'Ctrl' Keys simultaneously and keeping these pressed down, double click the RIGHT MOUSE BUTTON. Here comes the maintenance window!
On this window, you can perform the necessary maintenance. After that click on 'apply', then on 'OK' then close the window, turn the printer off and again turn it On to apply the changes made.