CTP Plates ECO3 problem

[craveiro]

hello, we are in the print shop using CTP Screen PLATERITE PT-R4300 E (THERMAL) and ECO3 plates and some when put in the Sakurai printing machine are getting stained as shown in the photo! Does anyone know why? Some are ok, others are not! Thank you

 

[Magnus59]

Looks like you need to change the startup sequence on the press, allow a few more rotations on dampers only prior to dropping the inkers

 

[maxon]

craveiro, what type of plates exactly ? Have you used them before or first time use ?

 

[craveiro]

craveiro, what type of plates exactly ? Have you used them before or first time use ?

I use ECO 3 Eclipse Thermal on a CTP Screen PLATERITE PT-R4300 E! reveals perfectly but when placed in the printing machines it looks like this (foto). We have been using it for about 3 months and it is only now that it has started to show these defects.

 

[craveiro]

 

[prepressdork]

Did you recently install a new batch of plates? It...could...be a bad batch?

Did your pressroom recently change anything like fountain solution or fountain solution dosage? Did they turn down their water on press? Blanket/packing material issue? Pressure/vacuum? Do you have another press you can test these plates on to see if the problem goes with it? Did they change ink by chance?

How far into the press run does this toning appear? If immediately, it might be a plate problem (I am hard pressed to believe it is a problem with the platesetter) but if later in the run, it could be press friction causing the non-image areas to start toning.

 

[maxon]

Craveiro, toning on large areas on DOP plates points to either underexposure on incorrect cleaning sequence on press. Your Eco3 supplier should have instructed your pressmen regarding coating removal. First thing clean you ctp optics, recalibrate and retest. If result is better but not perfect, increase the laser exposure in media type setting.

 

[maxon]

The Eclipse plates are negative working, their standard sensitivity of 120-130 mJ/sqcm will decrease if stored in cold environment or stored for more than 12-16 months. Check the expiry date on the label. Allow plates to acclimatize in the ctp room properly for at least one full day prior to exposure.

 

[craveiro]

I use this product and it's OK! Cleaning first the plate before input on the printing machine! Yes the climate is important, I have 89% humidity is azores island... Need a place to store the plates conveniently

 

[maxon]

Is it newspaper printing ? If so, a bit of plate cleaner should be ok(ish) but beware of coating residue recontaminating the plate in non-printing areas, I would only use cleaners as a last resort. Instead of Imaf use a softer cleaner like Alunet, specially formulated for ctp plates.

 

[prepressdork]

Is that plate cleaner compatible with the Eclipse plate (according to ECO3)? We use Antura plate cleaner.

 

[craveiro]

Yes, the supplier indicates this product, but I have some doubt

 

[maxon]

Antura and Alunet are good quality I used them both you don't risk removing or softening the image. Try Antura first it's the Eco3 product anyway. This plate cleaner thing is a temporary workaround you must solve the plate storage problem ... ideally run AC in the ctp room longer times to keep temp and humidity within normal range.

 

[Nephyrium]

Craveiro, toning on large areas on DOP plates points to either underexposure on incorrect cleaning sequence on press. Your Eco3 supplier should have instructed your pressmen regarding coating removal. First thing clean you ctp optics, recalibrate and retest. If result is better but not perfect, increase the laser exposure in media type setting.

Our plates provider did mention something regarding underexposure, he should be here in a month or so, and we'll remind him to double check, just to make sure - Would you happen to have your values, at hand by chance? Oddly enough this problem persist, mostly, on yellow and black plates (CMYK Engraved)

 

[craveiro]

Problem video.

 

[maxon]

This looks like press related.

 

[prepressdork]

I agree with @maxon. If the problem were due to underexposure, you would be seeing the issue shown in the video in all non-image areas and not just on certain parts of the plate. Roller problem?

 

[Nephyrium]

Update: Turns out the problem were the plates all along - we got a new batch yesterday, tested them out and they came out, perfectly clean with some adjustments.
Also, I'm just starting out my career so I'm fairly new to this - @craveiro is the more experienced person to explain what exactly is going on.