I've been having fun learning how things worked inside my retired Canon Pixma MX340 multi-function inkjet. Some lessons have direct application to personal projects, especially regarding components that I think I can repurpose in the future. Others are more general, like clever mechanical design concepts that I might be able to adapt to a 3D printed future project. Then there are lessons just for the sake of satisfying curiosity. Looking at implementation details of the paper tray sheet feeding mechanism, I'm definitely in the territory of that last category.

Designing this mechanism took skill beyond what I can comprehend today, orders of magnitude more sophisticated than my 3D printed mechanical contraptions. Part of this stems from the fact I haven't built up the mental skill to organize knowledge of complex mechanical interactions. My software background gave me ways to think about software interactions, organizing them into API layers and partition module interactions into various levels of abstractions. Looking at a mechanical gearbox where forces can be transmitted via multiple paths to the same destination, at gears that only have teeth to transmit power partway through their circumference, at the freewheel element that turns one way but not another... my brain is overwhelmed trying to keep track of all potential interactions.

I think a good analogy is learning a new language. (The human spoken kind, not the computer programming kind.) It takes some experience to learn enough to mentally catalog and partition the sounds we hear. Knowing where one word ended and another began is an important early skill. Knowing what sounds are critical and what sounds are just person-to-person variation is another big step.

At the moment I lack the equivalent skills to understand and analyze what's going on inside this gearbox. I also lack the motivation to understand designs optimized for mass-production, which I don't plan on doing. In other words: if I put in the work to understand it all, I would learn some very domain specific knowledge on a cheaply mass produced mechanism to feed the top sheet of a stack of paper. I don't foresee that knowledge as something useful to me in the near future. The cost/benefit ratio for diving deeper into this gearbox doesn't look great, so I'm going to stop here.

Still, I've learned a lot of interesting things, and I'm confident this exposure will help me understand more of the next mechanical marvel I encounter in a teardown. A process I intend to repeat until that day when I can look at a complex mechanical system and not get overwhelmed. An iterative process starting with admitting that day is not today, allowing me to focus on other lessons I can more easily absorb.

This teardown ran far longer than I originally thought it would. Click here to rewind back to where this adventure started.