my hp psc 2175 all in one?

My printer starts up and makes a noise not a hum but does it every half second then it starts to click in time with the noise the computer says scanner is not working and to turn off printer and then back on again but the same thing happens, I used it this morning with no problem. It has happened before and when you come back later and switch on it has been okay this time taking all the plugs out and leaving it has no effect, any ideas.
Thanks.
Paul