Epson Stylus Pro 4000 Reference Manual page 190

1. Select On as the Background Printing setting in the Chooser
or in the Background Printing dialog box.
2. Send a print job to the printer.
3. Select EPSON Monitor IV from the Application menu at the
right end of the menu bar. The EPSON Monitor IV dialog box
appears.
Note:
You can also open EPSON Monitor IV dialog box by double-clicking
the EPSON Monitor IV icon in the Extensions folder.
190
Printing with Mac OS 8.6 to 9.x