plate scumming

Bret Hesler

Well-known member
Is any one experiencing scumming or sensitivity within images during the run on Heidelberg Saphira Thermal PN or Agfa Energy Elite plates? Had this problem at another shop, and never really had a resolution to the problem, it would just come and go.

Thanks,
Bret
 

TheProcessIStheproduct

Well-known member
Had similar problem on energy elite, was just testing so did not try a bunch of things, but seemed like OK with new chem, but 1000 plates or a month into chem had scumming, and picture framing...
 
dear friend i hop that ur replishment is not in correct because ur saying that scumming occurs when 1000 plates cover that means ur dev is been weak .any way u check the ph of dev every week .increase the replishment rate if required.hop that will help u .,
 

rbailleu

Well-known member
did anyone ever find a solution to this issue. I have something very similar on chemfree 101
 

rbailleu

Well-known member
hand gumming with the gum from the clean out unit has helped us. next trial new fountaion solution.
 

Johnboy

Member
few years ago we had the same problem and discovered they had reduced the silver content which caused problems..we changed our supplier and cured the problem...
 

rbailleu

Well-known member
I will know more tomorrow. but our issue may have been a combo. blanket over packing, ink and water rollers set poorly.
 

Perryt

Member
We switched to Fuji Pro V Low Chemistry (this is where the gumming solution processes the plate) last year. Initially we had problems with scumming and picture framing. We found that the problem was that the fount and ink were not totally compatible and had to find a more suitable ink and fount solution.
We have also found that we need to pay more attention to the PH of the water and monitor the RO system.

I beleive the operating parameters for this style of plates are more stiringent than that of traditional offset plates.
 

Himanshu_Monotech

Registered Users
Dear Friend,

For this Prb lots of causes like chemistry of Processor,Brush speed, washing section Brush is working or Not.
But I am sure This problem from processor side.
 
After answering the following questions you should be pointed in the right direction:

Does the problem happen just after you have (A) rebatched the processor(fresh chemistry) or (B) after a couple weeks of use?

A, then it is NOT replenishment rates, try adjusting the processor settings to the following: DEV temp:24c, Speed/dwell: 85 cm/m2 or 25 secs (Letting the plate sit in the soup at higher temp and longer time will clean the plate out better), It should only change your 50% dot about a 1/2%

B, then it could be replenishment rate or possibly a defective repleish pump or improper pump calibration, set the replenishment rates to 70-90ml/m2 for usage and 40-50ml/hr for oxidation and standby modes

If either of the above doesnt solve the issue proceed to the next question.

Does the problem happen on multiple press'?

Yes, Then I would look at fountain solutions mix ratios. The non-image/background of the plate is NOT being protected. Does the tinting/toning start right at roll-up or into the run? Are you using a 1 step fountain solution or a 2 step, you can add .5oz/gal of fountain solution to get more gum in there. This is easier in a 2 Step fountain solution setup.

No,
if only one press is having the issue, then is it happening the same on all units? Does it happen every job? is it happening with only 1 operator? Does it happen on a certain stock? Stripe and set the dampening rollers on the units that it is happening on.

I hope this helps.
 

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