They could provide Starbucks branded ink of which 95% of the cost is licensing fees which they pay out tax-free to themselves.

They could scribble each customers name on the printouts with a sharpie

"Got a flat black and white parking ticket appeal form for Kim"

- Name?

- Sauron.

- Sharon it is.

Maybe they could do some R&D to see if coffee could be used as ink.

I just put coffee in my printer to see...

It kinda works, but the printouts are very faint.

I was expecting it to clog immediately (the jets are ~10um), but it didn't.

Damn. The kind of friends I need in my life.

Sorry to bother you but I have so many questions! Like, did you actually do it or was it just a middle joke I didn't detect? If the former, wasn't you afraid the printer won't be usable after that experiment? Didn't that worry you? Do you often experiment in this way? (Just stopping there to give otherwise the list gets too long.)

I have literally hundreds of HP print heads from a project, many partly blocked or burned out (they burn if you send them the wrong signals, and like 10% of the time I hit 'break' on my debugger it burns a few jets out if they're firing at the time), and had a coffee sitting right next to my desk so thought "why not".

yeah, but can you bubble jet maybe a photo onto a flat white?

That is a stretch goal of my project, but right now I wouldn't be confident I have a method to flush out the OEM and probably toxic ink.

This is incredible - you should write a blog about it. I want to see what that printout looks like!

When the main project is done, there'll be a blog post and the coffee test will make an appearance!

I'm also super curious what one might get up to with that many print heads, so maybe there's two posts in there!

I'm not surprised if you used the Breakfast Blend. Did you try the Caffe Verona or Espresso Roast?

It was Lidl's red topped instant - don't even know the name - the jar with the red lid, and I made it pretty strong but without milk/sugar (which I thought would cook/burn onto the inside of the nozzle)

That's my printer recommends Bulletproof Coffee. The coconut oil helps ensure smooth flow without clogging while the MCTs improve coffee adhesion to the paper.