Galileo VS8 - plate imaging problems

[RVNG]

Strange issue... The pressman tells me he always has problems fitting the cyan plate. It seems to be slightly compressed in size with respect to other plates in a process job. My only guess is that cyan is the first plate imaged in a process job, so... something about the laser perhaps? Or the vaccum? I am not sure what’s going on here.

If I run the cyan twice the second one is good. Any thoughts?

Thanks RG

 

[TechDoc]

In which direction is it compressed ? FastScan (Beam writing direction) or SlowScan (Carriage travel direction ) ? What is the resolution of that job?

 

[RVNG]

Hello TechDoc,

It would be Fastscan I guess, compressed between gripper & tail of a 28x40 sheet.
Res is 2400 dpi.

RG

 

[VladCanada]

If you do not see any artifacts on the image - possible vacuum problem.
Delring piston wedged in wrong position and too much or too less vacuum surface vacuumized to keep the plate pressed to drum...or low air pressure at air inlet, dirty air filters or water trap.

 

[RVNG]

Hi VladCanada,

Water trap has some liquid but is below the level indicated as maximum but 3/4 inch. I have noticed during imaging the air pressure meter wavers between 65-80 psi. When not imaging the reading is 110 psi.

Thanks for yor response,
RG

 

[TechDoc]

I agree with VladCanada... Could be a problem with vacuum, which is created from air-pressure...

 

[RVNG]

Thanks TechDoc,

As far as anyone knows does the 65-80 psi range sound normal while imaging? To be honest I had never looked before this problem so I don;t a frame of reference.

RG

 

[VladCanada]

Air Supply - The handler (Plate Manager) requires connection to an air supply that is dry,
oil-free and filtered. Air consumption is 10.5 ft3/min (CFM) at 100 lbs/in2 (PSI)
or 6.8 BAR with a Duty cycle of 78% at full rated throughput.
Engine Air Supply - The engine requires connection to an air supply that is
dry, oil free and filtered to a 20 micron particle level. Air consumption is 12
ft3/min (CFM) at 100 lbs/in2 (PSI) or 6.8 BAR with a duty cycle of 75% at full
rated throughput.

 

[Armya Inc]

You issue is easier than what everybody thinks.

Why we only have problem with Cyan Plate(the first Plate), and not other plates. Vacuum problem is strange.

Please contact me. I will help you. It is easier than what everybody thinks.


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[VladCanada]

I'm not sure they have Thermal compensation feature at their machine, and description of the problem is not completed: do they have a problem at the first CYAN plate per day or at every CYAN in a queu?

 

[RVNG]

VladCanada, it is always the first plate after the machine has been sitting idle for awhile. If I image 8 plates back-to-back (CMYKCMYK) the first Cyan is the problem not the second.