DPM2340 platemaker - plate quality

[arrants]

My AB Dick DPM2340 platemaker is outputting poly plates(23512 material) that have a less-developed/ /under-developed area in the same place each time. It is on the same path as one of the rollers on the processor entrance assembly which is only a few month's old..

We have replaced activator chemistry, cleaned chemistry tubs, cleaned rollers, checked and adjusted for worn bushings, gears, etc. All of the mechanism that moves the material through the unit appears to be working correctly.

We checked plates that we used last week and could see the roller track very lightly on them. Maybe the problem was starting to show itself then but it didn't affect image quality.

The Presstek service tech suggested a couple of things which I did but that didn't solve my problem. I'm trying to avoid an expensive service call.

I can't produce usable plates right now.


Any help will be much appreciated.

 

[FFR428]

Is it a roller scuff or scratch? There are parts of the processor racks that need to come apart to clean and polish. Chemical residue is heavy normally between chemical changes. If for sure it's a scuff mark the plate and try to line it up with different parts of the racks. This might help you find it. The intake roller that feeds the plate to the tank from the drum can be a problem. The rollers can seperate from the shaft and spin or bind and mark the plates. So have a close look. If the plates are fogged/lightstruck either the roll of film was exposed at some point of the camera is letting in light. There's a free upgrade Presstech (Now Mark Andy) offers. It's a simple cover that goes inside the camera and helps keep light out. DPM's that are by windows or in bright lit areas are more sensitive to this. You can also try to adjust your exposure if the background areas pickup. This might help blowout the affected area enough to make plates until you correct the situation. So please elaborate a bit more if possible.

 

[Swifty2]

If it is not a light issue only thing I can come up with is the tension on the material is wrong?

 

[arrants]

Thanks for the help, FFR428 and Swifty2.
I did bring in a service tech. It appears that the problem was caused by a dirty mirror in the imaging unit.
Thanks again. Much success to both of you.