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Method and apparatus for monitoring plates in marking device

  • US 5,307,420 A
  • Filed: 03/16/1992
  • Issued: 04/26/1994
  • Est. Priority Date: 07/22/1989
  • Status: Expired due to Fees
First Claim
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1. A method for monitoring a condition of a printing plate during a printing process in a marking device for marking semiconductor devices characterized in that a camera is installed with its photographing side facing up at a position away from a workpiece carrying table which positions and carries a workpiece that is to be printed, a printing plate which is attached to a plate holder is moved to a point above said camera, and said printing plate is periodically displayed on a monitor during the printing process and a condition of said printing plate is periodically checked by means of said monitor during the printing process.

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