100% CPU when printing

This all depends on the printer server model you are using. You would need to provide the type of print server you are using. I have few of these lpt to usb and the problem is a lot of times it wont pickup the pc side the device. You would be better off getting a lpt to network they tend to work a 100 times better.

It really depends on the specific printer interface you have!

Newer printers can be attached to a Desktop or Notebook via the USB interface (small connector as for mouse).

Older printers, and 'commerciall' high speed printers, have a 'parallel' printer interface (large connector - LPT port) that will connect to a desktop (or higher end laptop) with a parallel (LPT) printer port. If you need a LPT connection, a USB to LPT converter can be used ... but a newer USB connected printer may be a cheaper alternative in this case!

Hope it helps let me know how you go.

Try this if connected parallel:

This error may occur if you have a computer with an ECP port in Windows;
INCOMPATIBLE PARALLEL PORT PROTOCOL: During the PLUG n PLAY setup, Windows usually sets the parallel port driver for ECP mode if the computer's hardware port is set for ECP or, in some cases, ECP+EPP. Windows 95 will utilize data compression during ECP data transmission which can cause "garbled information" if the receiving device, such as a printer, is not ECP compatible.

SOLUTION:
Change the Windows Operating System's printer port driver (LPT.VXD) to the standard mode (non-ECP).
Windows XP:
1. Click on "Start", then "Control Panel.
2. Double click on "System:, and click on "Hardware", then click on "Device Manager"
3. Click on "Ports (COM & LPT)" section, and click on "ECP Port".
4. Click on "Driver", then "Update Driver"
5. Click "Install from List or Specific Location (Advanced)", click on "Next"
6. Select "Don't search - I will Choose Driver to Install", click "Next"
7. Select "Show Compatible Hardware"
8. Select "Standard Port" on the left window and "Printer Port" on the right window
9. Click on "Next" and Click on "Finish" and close all windows
10. Reboot/Restart your computer to ensure the changes are activated.

How is this printer connected to your computer? Is it connected by a parallel/centronics cable, or USB, or perhaps not connected physically at all, but via network (it's a network-capable printer)?

Also, you don't specify the operating system.

I would guess, that it was installed on the LPT (parallel) port, instead of a network port, and because in reality nothing is connected to the parallel port it is producing an error (explaining why it's called busy would be long and boring).

Anyway, please either check the setting of the port to which this printer is printing (find that in Printer Properties), or be more specific as to what your current situation is.

You are correct on your deduction.
It is the USB to Parrallel adpter. They are not reliable in the XP/Vista enviroment. I have run into this several times.

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309