I'm taking apart this Canon Pixma MX340 carefully, hoping to keep all of its system in a running state so I can learn more about how it works. Lucky for me, Canon engineered this machine with disassembly in mind. I'm not sure of their original motivation to do so, but it was an appreciated surprise. Given the nearly disposable nature of printers in the inkjet economy I had half expected something glued together.

I started looking for ways to get into the printer from the bottom, where the product label lived.

Also accessible from the bottom is the AC to DC conversion power supply. Held in place by a single plastic tab marked in this picture with a red oval. Given this unit is listed to accept 100V AC and output 24V DC, I assume a different unit is used for sale in countries with 240V AC. The AC input side uses an IEC 60320 C7/C8 "figure 8" connector and the output side has three wires (white, blue, blue) just visible to the left in this picture.

I found no exposed fasteners on the bottom. I found two exposed fasteners in the back, and removing them freed the rear panel.

Behind the rear panel is a circuit board, looking like the brains of this whole operation. Roughly a dozen connectors carry power to and data from the rest of this printer. As this teardown proceeds I should get an idea of the purpose for each of these connectors. I can start with the white-blue-blue wire just below the center: that receives power from the power supply and it makes sense majority of capacitors are clustered around that area.

Above the circuit board, I can see there are no fasteners or clips holding the paper feed tray in place. It can be removed by bending the plastic away from plastic nubs acting as hinges.

Removing the rear panel also exposed this fastener for a side panel.

The same panel has a fastener on the front, accessible by lifting the scanner module.

After removing those two fasteners, I yanked on the panel and it came free but not without damage. There are two long clips in the middle of this panel. The rear clip survived but I broke the front clip.

In hindsight, I see that Canon engineers had placed hints on how to release these clips without damage. Small rectangular holes were cut into the surface, with small triangular arrows drawing attention to them. I noticed the arrows earlier but I didn't know what they meant! Now I understand this symbol and shape mark locations to access clips for removal. And once I knew what they meant and knew what to look for, I see them all over this printer. Thank you, Canon engineers!

Now that I have this knowledge, I could remove the other side panel without damage. Unfortunately I could make no further progress taking apart the base at the moment. I have found more fasteners, but they are blocked by the hinged scanner module above. My next step will disassemble the automatic document feeder at the top and work my way down to the base.