Through the back of the paper you can see how the stamp pad ink bleaches the black from the thermal image, leaving red on a light background.
I found this wireless thermal printer at Deseret the other day – for $2, I had to check it out.
It takes a thermal roll almost an inch wider than the Phomemo M02.
Made by Amazon, and intended to be used on an Alexa network. On reading up on it, it apparently has broken IPP implementation that makes it only useful if you have an Alexa system. I don’t, so it’s e-waste to me. Ahh well, what say we open it up and see what’s inside these thermal printer gadgets!
Screws under the feet.
The body plastic was made in 2021.
Not much on the logic board except a wifi module, power circuit, some small logic chips and a speaker(?).
Screwed into the bottom is this several-ounce metal plate, just there to add a little heft to the thing. I may have mentioned that Smith-Corona did this with “office” typewriters in the 70’s, which were just the regular portable electric model with a deeper bottom tray and weights bolted in to make it even heavier. How much expensive waste this sort of “it’s heavy, so it must be high-quality” thinking adds to global product transport costs is probably depressingly high.
Another small board for the power switch and its logic. Made in 2020,
This assembly contains the print head, feed rollers and a powered cutter blade. It’s links to a motor module that actually drives the gears and levers the blade.
The motor module. What looks like two(?) stepper motors to control paper feed, and one big one to operate the cutting blade.
Not much inside these things, and very modular. I can see why these things are cheap to produce.
You could maybe save the motor to play with on an Arduino.
I found a number of tutorials back in the day about adding new firmware to these sorts of thermal printers that allows them to be used with a laptop or a phone. It was outside of my capabilities but very interesting.
I thought about that, but there’s no way to get data on the device without an Alexa to set it up, so it seemed more interesting to open it up and see what’s inside :D