Removing the toner cartridge revealed two white plastic brackets supporting the main D-shaped feed roller. I detached these and released the roller. It was a bit shiny on the business (fat) side so I cleaned it and removed and replaced the rubber covering to present the unused side. I had great hopes at this point but re-assembling and printing produced the same results.
Next? Looks like a 2 inch by half inch pressure plate is not pressing adequately on the roller. The spring might have weakened.
All advice/encouragement welcomed.