If your printer isn't printing a nozzle check pattern then it is likely that your issue is with your Epson printer rather than your iMac. I suggest contacting Epson for support.
Has the printer been sitting unused for a long period of time? Ink jet printers can suffer from clogged nozzles if left sitting unused for long periods of time.
Here's how to access the printer's built in diagnostic test page that will quickly determine whether the printer is the source of the issue. I pulled the information from Epson's online manual. I suggest using the link to get to the manual, then select the 'Diagnosing Printer Problems' section, and use the instructions in the 'Running a Printer Check' section.
https://files.support.epson.com/htmldocs/sc88p_/sc88p_ug/wwhelp/wwhimpl/js/html/wwhelp.htm
Running a Printer Check
You can run a printer check to determine whether a problem comes from the printer itself or some other source.
1. Make sure both the printer and computer are turned off. Then disconnect the interface cable from the printer.
2. Make sure letter-size plain paper is loaded in the printer.
3. Hold down the paper button, then press and release the power button. Continue holding down the paper button until the green power light starts to flash, then release it.
A test page prints showing the printer’s ROM version number, an ink counter code, and a nozzle check pattern. (If the pattern has gaps, you need to clean the print head.)
4. Turn off the printer after it prints the test page. Then reconnect the cable and turn on your printer and computer.
• If the test page prints, the problem probably lies in your software settings, the cable, or your computer. It’s also possible that your software may not be installed correctly. See your Start Heresheet for instructions on reinstalling the printer software.
• If the test page doesn’t print, you may have a problem with your printer. Try the suggestions in Problems and Solutions. If nothing works, contact Epson as described in Where to Get Help.