Solution found: HP Support gave me another printer driver: HP Universal Print Driver for Windows PCL6 (64-bit) Version 6.2.1.20636

Now it works on all devices.

Thanks for the help!

I don't know how to help you exactly. Can you be a little more specific? What steps have you already taken?

The devices are definitely compatible with Windows 7/8/8.1/10 32-64 bit.

What port are you using to connect the PC to the printer?

Do you follow the installation instructions exactly?

Are you using the latest drivers from the manufacturer's website or from the CD?

Have you already tried to install the devices on another computer?

The devices are integrated into our company network, wired, WLAN is switched off. They have an IP address via DHCP and work perfectly from any Windows 7 computer with 32bit.
With Windows 7 64bit and Windows 10 64bit it behaves very strangely: With Win7 I can print e.g. PDFs and JPGs...but everything that comes from Office programs (Word, Excel, Powerpoint) does not work. Excel immediately gives an error message, Word pretends to print but nothing arrives at the printer. With Word the printer reacts, it opens the cover and rattles a little...but nothing else and the cover closes again.

With Win7 and Win10 I can't send a test page from the printer properties, a message appears immediately that it has failed. Troubleshooting, as is usually the case, brings up an unknown error.