I have an awesome Canon Pro-1000 printer that I use to print out photos. This isn’t about the quality of the printer as much as being able to take a video of it printing.
Every panel on the printer has a sensor so the printer knows when any part is open. Even mundane things like the cover of the rear tray has a sensor–this isn’t the rear tray itself, just the tiny clear plastic bit that covers a gap. Whenever anything is out of place the printer goes into a safe mode and stops printing. Honestly, that makes sense because you can easily get foreign-object damage if something falls in and that can get really expensive really quickly.
But back to video.
To get this shot I have to close a microswitch on the top of the printer lid:
This seems like it would be the job of a paperclip or something, but it’s harder than that. The switch is exerting enough side force that it wants to make whatever you put in pop back out; Canon though about idiots like me.
Enter a slightly modified 3D printed part:
I had to modify it because even though it fits perfectly, the spring tension from the switch still wants to pop it out. I could easily print an alternate version that has this extra lip, but I didn’t need to. The lip catches on the underside of the printer cover assembly preventing it from getting ejected. (The printer lid normally presses down on it, but it weights around a point or so and doesn’t have a problem overcoming the spring tension.
Now the printer thinks the cover is closed!