🚀 go-pugleaf

First thing to do is to try selecting Print As Image in your printer setup.  If the graphics are printed correctly, even though very slowly, with Print As Image selected, then it is surely your printer driver. You don't mention the brand name of the printers, but i can guess they are Hewlett-Packard, because I know HP has yet to develop a driver that works with Acrobat or Reader 5.x. 

As to acertaining how these PDFs were created, you select File>Document Properties>Summary and it will tell you Creator, which is the original document format, and Producer, which is the program used to convert the document to PDF.  It will also give you other pertinent data such what version of Acrobat it is compatible with, file size, security settings, and whether it was optimized (fast web view)