A hard-surfaced variety of intermediate roller found in the inking system of a printing press used in offset lithography. Riders, in contrast to distributors, typically only contact one other roller (such as an oscillator) and do not transfer ink, their purpose being primarily to provide an added "detour" which adds additional forces to the ink so as to work it into a suitable viscosity and thickness for proper printing, needed due to the thixotropic nature of lithographic printing ink. Riders have the smallest diameters of all the rollers on an offset press, and consequently have the highest number of revolutions per minute. They turn by action of frictional forces generated on their surface by adjacent gear-and-chain-driven rollers. (See Inking System: Offset Lithography and Offset Lithography.)
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