This is a known problem with the LaserWriter family of printers that is particularly noticeable when printing to a LaserWriter via a LaserShare or an AppleShare Print Server. Macintosh Technical Note #123 describes the problem.
If a user prints more than 15 copies of a document, a timeout condition may occur, causing the print job to abort. With LaserShare or AppleShare Print Server, this problem can happen with as few as nine copies. This problem is a result of the LaserWriter not sending packets at the proper times to maintain the connection to the device sending the print job. Because of this, the connection times out after about 2 minutes. The AppleShare Print Server then sends the job to the LaserWriter again causing a duplicate set of printouts. This happens only when the LaserWriter is extremely busy.
The LaserWriter IINTX seems least affected by this problem.
As of April, 1990, we know of no solution.
The following Tech Info Library article can help you find the Tech Note mentioned here:
Article 24493: "Apple Tech Notes: What They Are, Where To Find Them"