Keep an eye on that printer! If it did not work "out of the box", quite possibly there is an undiscovered issue with continued reliable printing. Perhaps not. Use it, a lot! Particularly before the warranted period runs out.
Staples, WalMart, and other "fine" office supply stores sell pre-perforated paper just for this purpose, using an Avery template for Word. I use this card stock from these suppliers all the time!
The papers are designated for either Inkjet or Laser printers. Choose wisely...
Unexpected "programming".
Why not just leave the sensor active at all times (including a 'sensor test target' on the carriage to confirm it's always working) rather than "delay" it's rather important function??
I didn't realize raw materials for 3D printing required "dehydration" to improve results, but it does make sense!
Just like dry mounting a print, both the print and substrate should be dried (in the press) before mounting, else bubbles (from moisture) may occur after mounting.
Hopefully you allowed the print head to cool before using it? I would only have printed nozzle checks (if the HP has that feature) before challenging the print head with solid bars...
Can't argue with success, though!
...MALWARE!
See here:
https://askbobrankin.com/is_it_safe_to_buy_a_used_computer.html?rankin-usedpcs=&utm_source=newsletter&utm_medium=email&utm_campaign=january_newsletter_5&ad_id=505874&share-ad-id=1
LA Awesome contains "some" Sodium Hydroxide, otherwise known as lye.
Very hash stuff! NEVER let that get near a print head.
I always final flush with distilled water, as the residual contaminants in de-ionized (softened) water are really unknown.
Water is strange stuff. It is REALLY...
Some use dishwashing soap (Fairy?) instead of Original Windex, since ammonia is under restrictions in some countries.
Distilled water is recommended as a final rinse (or two) to remove ANY hardness minerals from the cart.