Note: The above links were compiled in the late 1990s. Now, in the post-2000 era, some of these links may now be out of date. During 2010~2020, the world of motion control has used to be purely in the industrial market, but has now spread to consumer markets with the advent of in-home 3D Printing and both small and large scale CNC equipment.
There's a lot of overlap between those applications and optical printer automation. This means the cost of motion control equipment has been reduced, opening new avenues of sources for equipment now with broadened competition. As an example, micro stepping drives started out in the 1980s with Centent drives being around $300, then in the mid 1990s Gecko Drives became available for about half that price, and now stepper drives of similar quality are available from Amazon for around $20.
See also "Electronics Supply" (below) for other sources of motion control equipment.
That said, many traditional industrial sources are still available, such as Gecko Drive, Centent, Omron (Industrial Automation Division), Anaheim Automation, etc.