HP OfficeJet Pro 7740 Wide Format All-in-One Printer
Email address for printing PDFs: 89ith27etcab@hpeprint.com
Ink replacement
If you need new ink, don't buy HP ink. There are cheaper alternatives such as WOKOK remanufactured 952 XL Ink on Amazon.
Some off-brand inks don’t work such as this one.
Troubleshooting
Printer is OFFLINE
If the printer appears to be offline, run the printer troubleshooter on your Windows computer. Oftentimes, it wakes up the printer again. Alternatively, you can use print from your iPhone, which works more reliably than printing from Windows laptops. You can also send a PDF to the following email 89ith27etcab@hpeprint.com.As your last resort, you could try to use this HP Print and Scan Doctor application.