Q1. What is the data that tells the printer to select a paper tray as a setup for a print job? If I knew this, I could script “set tray #1” vs. “set tray #2” ahead of my jobs.
Q2. Is the tray setting process different when I send data from a CLI vs, from a browser, LibreOffice, or other application?
Q3. Since most Linux printing uses CUPS, how do you suggest that I discover if that is the culprit instead of HPLIP?
The HP 7740 has two paper trays. Tray #1 (upper) has fetures for all sorts of paper formats – letter, legal, tabloid, envelopes, index cards, etc. Tray #2 (lower) is only able to handle sheet goods – letter, legal, tabloid, etc.
When you open a tray and then close it, the printer console prompts so that you can modify the paper installed in the tray. (It does not care if you closed to tray without altering what is installed.)
There is a console setting to select the “Default Paper Tray”. This default gets used when there are no instructions in the print job to request a specific paper tray.
Thank you in advance,