Clamping apparatus for disk-shaped information medium having a central hole, the disk-shaped information medium having a surface upon which information is to be printed, including a baseplate having holes; a slider guidably mounted on the baseplate for centering the disk-shaped information...http://www.google.com.hk/patents/US5824388?utm_source=gb-gplus-share專利 US5824388 - Clamping apparatus for imprinting disk-shaped information medium
