Dolev 4press; Dolev 4press V; Dolev 4news - DOUBLE EXPOSURE

Author/Submitter: G. Menchik (03/31/98)
Document Released: 03/31/98

Product Family: Imagesetters / Platesetters

The "DOUBLE EXPOSURE" issue was reported from the field and was checked in R&D. For those of you who are not familiar with the above issue some more details are given here. On the XPress family (especially on the 4News) we have sometimes seen the phenomena of two or more files being exposed on top of one another without advancing the film.

The reason for this phenomena is that the S/W is not responding correctly to some error state (like Cutter stuck or Processor busy and other failures).

The new 4News S/W that we are currently testing will detect those error states and will deal with them correctly. But we have to remember that S/W is not Magic. If a problem such as the Cutter is Stuck or an Attached Film Crash occurs during exposure ( i.e. On line processor vibrate the machine and if film encoders are not tightly attached to shaft or film we get false pulses) we will get an error message (but we will not get the error message "DOUBLE EXPOSURE").

When we analysed some films and Log Files from the NYT (sent by Paul Willis) we realised that most of the "DOUBLE EXPOSURE" cases were related to operator mistakes (caused by wrong leading of machine error messages) .

Operators need to understand that whenever the exposure is aborted for any reason (except abort by user from the TP) the exposed film will stay on the drum and the next exposure will not advance the film and this will cause a "DOUBLE EXPOSURE".

We have to instruct the operators to do the following after any abort due to machine problem:

1. Cut and collect - To eject the film that was previously successfully exposed .
2. Advance 500mm of film - To eject the aborted file and "clean" the drum.
3. Now the machine is ready to have the next file on a "clean" (not exposed) film.

Soon we will end our testing and we'll be able to start installing the S/W for Beta testing. Instructing the operators is not less important so please pass them the above information.