Karnage
I-am-a-pirate. I do not need credentials!
Doesn't Big D still use those? Aren't they the only thing keeping that paper company an ink cartridge company alive?
Okidata seems to be doing quite well, at least based on their prices. Delta has been slowly updating to the latest version of this:
http://www.oki.com/us/printing/products/dot-matrix-printers/9-pin/microline-420-421/index.html
On the other hand, the boxes of paper did seem to indicate that the half sheet perforated form feed paper was custom made for Delta, or at least the part number seemed to indicate as much anyways.

