Innovation Gallery


The grit wheel plotter used sandpaper as a practical solution to an engineering problem.

Model For The Grit Wheel Plotter, 1976

The grit wheel plotter was invented by an HP engineer named Larry Labarre, who worked in HP Labs from 1952 to 1983. He was a mechanical engineer, and his reputation for creativity, inventiveness, sound implementation and independent thinking was legend. One day, while struggling to build a personal computer plotter, Bill Hewlett said to Larry "What we need, Larry, is something that can move this paper back and forth without slipping."

In a previous job, Larry had had some experience with knurled power feed rollers used to drive lumber into a saw. In about two days he came up with the simple, elegant solution of bonding a ring of 80 to 120 Carborundum paper around the paper drive roller. The sandpaper would grab the paper and move it. A patent was applied for on October 24, 1980.

In 1986 Bausch & Lomb sued HP claiming that Larry's invention was not still the "best way" and the patent should not be allowed to persist. By then HP's San Diego division (Currently HP's Imaging and Printing Systems business) was dipping the wheel in epoxy and then applying grit to cover the glue. But on the stand, Larry steadfastly claimed that his method was still the best way and the least expensive means to the end. HP prevailed, and Larry's patent was sustained.