The State Library of NSW holds a collection of Library bookplates, including one from the Jayar Studio Library.
There are US reprint stories signed 'Jayar' in Crack Western #1 and Screen Story Comics v1#5. The signature should not be taken seriously, as the changes involved at most tracing or fixing unclear originals, and amending artwork to fit different page dimensions.
What might 'Jayar' mean? It seems to be an uncommon English given name (based phonetically on on the initials J.R.) and a rare family name. It is also used as a nick name for 'junior' (Douglas Fairbanks Jr. referred to himself as Jayar) and for people whose name has the initials "J. R.". It was the name of an Australian brand of cigars in the thirties, owned by John Rankin.