Strangely,after lots of canvas printing now,it started today also with my printer.
On both sides in the printer bay,is two ink tanks,with absorbtion pads.From time to time,one would see the carriage stop first on the one side,and then on the other side,doing a head clean.The ink later thickens on the pads,and thus,tiny droplets of ink,forms under the head,which then drops onto the print.
If you shine with a small torch into the bay,you will see a pad,with diffrent ink colours on it.And the black,due type of pigment,dries up,thus,pad cannot soak up,the ink released by the nozzles,hence it clings to the head.
The one on the left hand side,can be reached,without much hassles.The lid,has got a clip,which you press,and the top inkpad,comes out.I first clean them with surgical alchohol,then just rinse properly under a tap,and dry.
The one on the right hand,you move the carriage by telling it,you wanna do a head change.Then,once the carriage move into position,you switch the printer off,at the main switch at the back,and move the carriage little bit futher.Then you can reach this pad also.Same story,press clip,remove top pad,and clean.
Under both top pads,are wto larger pads standing upright.If these pads are soaked full,then you can wash them as well.HP wants us to swop them with new ones.NAHHHHHHHHHHHHHH,just rinse and put back.
Move carriage to the previous position by hand(in the position it parked itself,while letting it know,you wanna do a head change),and switch on.Printer wil start up,and all is well again.