Canon MP530 print head malfunction

I had the same problem with my printer. There is a switch that tells the printer that the cover is open or closed. Unplug the printer. Open up the printer cover and look on the inside right side edge. About half way back, you'll see a 3/4 inch by 1/2 inch hole where this switch resides. If you put your finger into it, you may be able to push on a lever and it will go down. It should spring back up when you pull your finger out. If you can feel the lever but it just sits at the bottom then there either this lever is broken or the spring fell off.

The problem with my printer was the spring had popped out. To access the switch, you'll need to remove the right side cover. Do this by removing the two screws in the back on the right side. Open the printer cover and find the third screw. It is located on the right hand side, near the front of the printer, on the top. Remove this screw and pop out the cover and see if you can find the spring that is attached to the lever. Make sure you do this in an area that if a small piece fell out you could find it.

Look at the switch and lever. If there is no spring attached to the lever then it is most likely the problem, otherwise the switch may be bad or the electronics inside the printer. There is a hook on the lever and one on the printer. Reconnect the spring and it should fix the problem. I found my spring had completely fallen out and fell on the floor when the cover was opened. It is possible that this spring if fallen out can fall back inside the printer so you may have to shake the printer to find this little spring. It is about 1/2 inch long. Hope this helps.

Do you mean the thing that holds 5 catriages? Sometimes, I keep it in the center by hand.Of course, you do not need always hold it. Once it stays, you can move your hands and replace catriages.