What is PSNormalizer / normalizerd process I am running MacOS 10.14.6 on an iMac, and have found that there is a process called normalizerd that is doing about 2TB of disk writes per day. 

Through some internet search, found that there is a system called com.apple.print.normalizerd, which appears to be initiated by an XPC(?) called PSNormalizer. I think this might be a background process, possibly connected to pdf/postscript, and installed by XCode.

A grep for PSNormalizer in /Library found entries like

Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/Library/PrivateFrameworks/PSNormalizer.framework/Versions/Current/Libraries/libICC.tbd:install-name:    /System/Library/PrivateFrameworks/PSNormalizer.framework/Versions/A/Libraries/libICC.dylib

Overall, I would love to know in more detail what this process is, and more importantly how to make it stop! Thanks a lot for any assistance.
I believe I now know what was causing this. I attempted to print to a Kyocera photocopier that doubles as a fax machine. This process seems to have been going around and around, attempting and re-attempting to create documents in a suitable format for faxing. I found the (unprinted) documents in a lingering unseen print queue. Having removed the documents, the uncontrolled disk writing has ceased.