Troubleshooting Slow Printing in macOS & Mac OS X

If printing becomes slow, try the following:

Make sure your system meets the requirements for your operating system. If you are printing a high-resolution image, you may need more than the minimum requirements. If necessary, increase your system's memory.
Clear space on your hard drive or run a defragmentation utility to free up existing space.
Close any programs that you're not using when you print.
If your product is connected to a USB hub, connect it directly to your computer instead.
If printing becomes slower after printing continuously for a long time, the product may have automatically slowed down to protect the print mechanism from overheating or becoming damaged. Let the product rest with the power on for 30 minutes, then try printing again.

Refer to below article: