AirPrint Problems and Missing Text
Since latest update 10.15.6 on my 2017 iMac my HP Photosmart 7520 Printer using AirPrint is not printing certain sections of text from either Pages documents or PDF's. It will print the boxes the text is contained in, and certain sections of text, it always the same sections of text that are missing. In certain cases it will not print anything on the page just churns out a blank page. If I take a Screenshot of the same documents the printer will print the document including the missing text perfectly, Preview will print JPEGS fine. This web page prints perfectly.
The printer test page is perfect when demanded from it's web interface on the iMac. I have no problems connecting to the printer and the quality of the Screenshot and test page means that the printing mechanism and ink are all working fine. Just these missing sections of text on PDF's and Pages (and also Numbers) documents.
The same is true for my other (ageing) MBP's running 10.13. And also my iPhone XS exactly the same problem. I have deleted the printer from the LAN switched the printer on and off and added again in System Preferences, but still exactly the same problem.
Anyone else having these issues and how do I resolve them? Indeed where lies the problem?
iMac Line (2012 and Later)