What happens if you temporarily disconnect the USB hub from the Time Capsule and connect the HP printer directly to the USB port on the Time Capsule?
Frankly, since Apple offers very limited printer support at the USB port of the Time Capsule, I would be surprised if the laser printer will work when connected to the USB port of the Time Capsule, but I suppose that anything is possible.
If the printer is not recognized when you temporarily connect it to the Time Capsule, then this tells you that it will also not be recognized when you put the USB hub back in place.
On the other hand, if the printer is recognized when it is connected directly to the Time Capsule, you have an issue with the USB hub.....not the Time Capsule.
If the printer is not recognized when you test by connecting it directly the Time Capsule, then your next option would be to contact HP support to see if they have any special software that would be compatible with the Time Capsule. If not, then your only remaining option will be to try connecting the printer directly to your computer to see if it will work that way.