Darill:
I had a problem with head strikes using Ilford Gold Silk at the very end of the printing when using sheets. The printer head would Hover, going back and forth, not advancing the paper at the end of the printing, which cause the head strike.
I updated the print driver on the HP web site (HP Designjet Raster Driver’ version 5.1) and the problem went away. At the end of the print the print head stops and the paper is ejected.
Jones