My ENVY 7640 says "Out of Paper" (nope), yet will print a Printer Status Report with no problem.

[Village_Mom]

Printer worked fine till yesterday. Now can't feed paper (unless printing an internal report doc) or see paper in tray. I've unplugged, cleaned rollers, then replugged. No change. Since it will feed paper to print an internal report, why won't it feed otherwise?

[OsSt]

Welcome to the forum. 
Ive seen this issue when Windows 10 updates the driver of the printer and sets a microsoft driver file instead of the HP. 
Please try to reinstall the printer using HP provided drivers from this link https://support.hp.com/us-en/drivers/selfservice/hp-envy-7640-e-all-in-one-printer-series/6617267/mo...

[Village_Mom]

Thanks for the suggestion, OsSt. I attempted to reload the drivers, but it failed, whether I used WiFi or USB cable to connect to the printer. I regularly use the HP Smart interface, and it shows the printer is ready to use.

It seems to be something with the printer sensing the paper in the tray with a print job that is different from when it is printing an internal report document.

[OsSt]

Please check the paper size settings 

[Village_Mom]

Settings are the same as always.
Is there a sensor on the printer that looks for the paper? Doesn't make sense to me that it will print an internal report without issue but cannot "see" the paper for a print job, whether sent remotely, or manually trying to print from the scanner glass.