Azura TE Light Sensitivity...

[kdw75]

We have been running CTP plates provided by a neighboring printer the past few months. We would keep them in the dark but then thrown them on the press and let them clean up without issues.

Last week we installed a Screen 4300 CTP using Azura TE plates. We are finding these to be much more sensitive to light. So much so, that we are having to mount them on the press with the overhead lights off and then once we drop the water and let them run a few minutes we turn the lights back on. So in summation, about 5 minutes of exposure to the fluorescents ruins them. We are running these on a 4-Color GTO with Crestlines. We are taking the plates out of the platemaker and putting them directly on the press without treating them in any way.

Any thoughts on this?

 

[gordo]

Have you tried UV blocked Yellow lights in the plate making room? I'm speculating cumulative light exposure.

 

[kdw75]

No. We have the plates stored in the original box. We then take it out and load it directly into the machine without delay. Once that is done, we run over and mount it on the press.

Looking at the sales sheet on these plates, they boast that they are able to be safely exposed to daylight for "Up to 24 hours". So something must be really wrong for us to be having trouble within minutes.

 

[kdw75]

Or perhaps there is some other issue besides light. I had the same problem and this time keeping the lights off didn't fix it. It seems hit and miss.

 

[kdw75]

This is an example. We took this plate and cleaned the background before mounting it. I would suspect the unit, but this seems like an odd pattern. I have checked all rollers and while they are swollen at the ends, we have been running up to this point without anything like this. Any thoughts?

 

[kdw75]

I tried pulling a plate off the bottom of the box and it worked perfectly even with the lights on. These were in two layers of packaging so I don't see how it could have been a light issue.

 

[chock]

Hi sir:
I strong recommend you to procedure the Laser calibration screen.
Have service manual for this manual.
Let me know.
Blessing
[email protected]
Mobile+WhatsApp:+505 8861 1441

 

[kdw75]

The installer said he calibrated it and set the focus. Do you think that could be causing this problem? If so I will do it myself this weekend. I have the manual and service manual.

 

[SnoopDoug]

So the bottom plate of the box was good? How far done in the box are they bad? Is it progressively better or is plate 15 bad and plate 16 good? Is the bundle emulsion up when you open the box? Interleaf and cardboard on top of plate?

 

[Alois Senefelder]

Hello kdw75,


The Photo you posted shows......... Residual Plate Coating, so what procedure DID you use to process this DoP plate - Hand or on Press?


Next time you have this Plate Problem do the following 1) Using a Plate Deletion Pen, delete a small area of "Scum" next Gum -up this area and buff the Gum Dry with a lint free cloth,


this Area should print clean.




Regards, Alois

 

[kdw75]

So the bottom plate of the box was good? How far done in the box are they bad? Is it progressively better or is plate 15 bad and plate 16 good? Is the bundle emulsion up when you open the box? Interleaf and cardboard on top of plate?

We started using off the top of the box as it lays with the emulsion up. The first couple plates inked up entirely. After that it seemed to be hit and miss with the bad ones looking like the photo. We were about 15 plates into the box when I tried pulling one from the bottom.

 

[kdw75]

Hello kdw75,


The Photo you posted shows......... Residual Plate Coating, so what procedure DID you use to process this DoP plate - Hand or on Press?


Next time you have this Plate Problem do the following 1) Using a Plate Deletion Pen, delete a small area of "Scum" next Gum -up this area and buff the Gum Dry with a lint free cloth,


this Area should print clean.




Regards, Alois

Most were put directly on to the press for cleanup. On the last couple we tried some alternative methods before haning on the press. We first tired wiping down with fountain solution several times until the towel looked clean, but the plate still had a purple tint to it. Then we wiped one down with a plate cleaner and preserver called hydroimage and another with Plate Savur. Both of these caused the background to look very clean like they should, but when mounted, still had the background pattern.

The one off the bottom that worked perfectly, we just hung on the press and dropped the water. It cleaned up in a few revolutions and ran perfectly.

 

[maxon]

Check interleaf paper sheets for wrinkles, slightest creasing indicates humidity in storage. Were the plate boxes allowed to acclimatize properly in ctp room. Do you control humidity in ctp area. Test clean a plate by hand again dropping a small amount of fountain solution allow to soak for 10-15 seconds then wipe in one pass with a clean white cotton towel, it must remove the entire coating in that small area. Rubbing repeatedly in one spot may in fact redeposit the pigment hence the toning.
Plates from box bottom were fine, this means laser exposure and focus may be set correctly. TE does need a lot of laser energy. Focus is critical. Check ctp final lens for ablation debris or dust, what plates did this ctp run previously ?

 

[kdw75]

Check interleaf paper sheets for wrinkles, slightest creasing indicates humidity in storage. Were the plate boxes allowed to acclimatize properly in ctp room. Do you control humidity in ctp area. Test clean a plate by hand again dropping a small amount of fountain solution allow to soak for 10-15 seconds then wipe in one pass with a clean white cotton towel, it must remove the entire coating in that small area. Rubbing repeatedly in one spot may in fact redeposit the pigment hence the toning.
Plates from box bottom were fine, this means laser exposure and focus may be set correctly. TE does need a lot of laser energy. Focus is critical. Check ctp final lens for ablation debris or dust, what plates did this ctp run previously ?

I am not certain. We just got this CTP and it is used. The plates came in, then were allowed to acclimate for 48 hours before opening the package and using them.

 

[Santa]

My TE plates sit out in full light before processing and after. I have the same engine imaging them so, it's either bad plates, bad laser set up, bad gum, bad clean-out unit or combination, but you should not be having light sensitivity.

 

[kdw75]

After the holidays and vacation, I come back to the same problem. We have run more plates for our smaller press, which uses 6 mil plates, and they all work perfectly. The box of 8mil plates though is still hit and miss throughout the box. I am notices that even if I had process them, they have splotchy areas where the background doesn't come off. Wouldn't the fact that the smaller plates work fine rule out the machine?

 

[kdw75]

Could the error: LD Power deviated from target power Ch. 0.1.2.3 cause problems like I am describing? We have gotten that twice.

 

[aqazi81]

Looks like a bad batch of plates. usually the thermal plates are not that sensitive to light. On the other hand CTCP or UV plates are more sensitive to light.

 

[yachtsman]

Agfa is not advanced Plate. This is negative plate - Write to Print. Put clear plate (no image) to print maschine, and run. No images = clear paper. Calibration
If its gets dirty, may be it is problem with water (osmose) or fount - changing water.
The best plate ist Sonora Kodak. No problem, no chemistry, large range sensitvity.

 

[jimas67]

I have been running these plates for years and never had a sensitivity problem, you could have a bad batch. What is the use by date on the box? These only really have about a year shelf life.