It appears that both the .printcd2 and .ec4 files come from Epson Print CD tool for making disc labels, so it's obvious that this software might help you with what you need. As for printcd2 to ec4 conversion, we have not found any particular information about this conversion so if you need help with export of Epson Print CD files, it would be perhaps best to contact their support or perhaps to reach out to the online community.
Updated: July 28, 2023