How To Replace The Left Reader Hinge

This video (https://www.youtube.com/watch?v=u0X7xmtKswg) shows the disassembly of a later, but very similar, model. The left side panel (viewed from the front) comes off the same way. Remove the visible screw in the back next to the USB plug. Use a flathead screwdriver to pry up on the plastic panel at the edges where a triangle-shaped arrow is present. The arrow points to the area to pry up on. The pry points are in the same place as in the video, but there is one additional one on the bottom at about the middle of the side, where the arrow is. Once those pry points are loose, the panel will come off. The electrical harnesses inside look identical to the video and comes apart the same way. Once the two ribbon cables are out of the way, and the other loose wires are out of the way, you can use your fingers to depress the black tongues of the hinges as shown in the video. Then you can lift the cover off.

My MF4450 broke it's left side hinge. The part that the screw goes through just shattered so that the spring inside the hinge lifted the left side up. My fix was to find a washer with an outside diameter of 1" (25.4mm), and a hole in the center big enough for the screw threads to go through, but small enough that the screws head didn't. I ground on the edge till I had a flat spot that provided enough clearance for the washer to clear the pivoting part of the hinge when installed. I then reinstalled the same broken hinge, with the washer on top of the hinge side flanges, and used the same screw. I then reattached the ribbon cables, rerouted the loose wires, slid the side cover back on, making sure each snap lock snapped into place, and installed the screw next to the USB plug. Cheap, easy, and much stronger fix!

I suggest you call in a Canon Technician, as there is no document or explanation on this.