Platen

The platen is a cylindrical roller, usually made of rubber or cork, that serves as the printing surface of most machines.

This page also covers feed rollers, which serve to friction-press paper against the platen and feed it forward when the platen knob is turned.

Construction

The platen is the dominant feature of the carriage of most typewriters. It is a long, usually cylindrical, object made up of a wooden or metal core coated in a softer material, usually rubber or cork. One end of the platen has a toothed wheel, which forms the line-spacing mechanism of the typewriter.

Feed rollers are usually machine-made metal cores directly coated with cork or rubber.

History

The platen began with the Sholes and Glidden typewriter as a faceted cylinder to provide a printing surface for the typewriter. Consecutive designs kept this element, but made it cylindrical to facilitate the feeding of paper with round feed rollers.

Maintenance

Many typewriters, particularly those manufactured before the 1950s, will suffer from hard platens. For these, the only long-term solution is to replace the platen rubber with new rubber. Properly recovered platens will have a hardness around Shore A 86. When working on a typewriter, it is recommended to clean the platen with a rag and rubbing alcohol. That will help it have more grip to the paper. If you're using a machine with a hard platen, inserting backing sheets is strongly recommended. They keep the firm rubber from sustaining damage or chipping as a result of the type slugs hitting it.

Temporary solutions exist in the form of rubber softeners, but these tend to be short-lived and damage the platen over time. A more permanent ersatz solution is the use of rubber heat-shrink tubing, generally to recover feed rollers -- though the method can also be applied to platens.

JJ Short and Associates of New York recovers platens.