I'm trying to swith off the printer, in user's guide I should press switch on/off button for at least 30 seconds (???) but then the green light on switch on/off button disappears, something inside the printer starts doing some sound like printing, 2 controls (WPS and !) are enlighted blue and green, after another cca 45 seconds it comes back to the only enlighted swithch on/off button. Pls help...I may take the cable out from electricity but I´d like to do it correctly. Thank you.