SM-74 Plate problems

Hi Guys
I seem to be having an ongoing problem with my plates hope someone can help.
It seems that most times after changing the waters in my 1995 6 col Speedy the plates become very resistant to picking up ink, we r using agfa azura ts plates.
Genraly my Monday morning maintenance consits of :
De-calcifing rollers (running de-cal wash with hot water then with febo clean)
Dump and re-fill water ( using Saphira Fs-13 fount@3% and 10% alcohol)
Clean delivery and filters
Grease up as required
I am using Xtrawash 60 as my roller and blanket wash (not by choice)
We have had no end of problems since switching to agfa azura plates before this we were outsourcing plates that were baked and had no problems.
I have mentioned on prevous thread (Plate Wear) that on longer runs the plates also tend to become ink repelant.
Coductivity is 800-900 ph is about 5.5.
What the hell am i doing wrong we have other presses who r running the same plates e.g Sm-52 that do encoyter actual image wear but not ink repelant as mine our.
Any advice would be gratly apprecited.
Kind regads Gazman

 

It seems to be that the cause comes from gum using for plate. Sometimes, the gum make plate can not recept ink

brgds

 

Someone mention to me that the agfa plates has problems. Not sure which Agfa plate. from what they have told me is if you have solvent on the blanket and it transfer to the plate there are problems.

You might want to bring up the conductivity to 1300-1600.

 

How would i go about increasing my conductivity?

 

Increase your fountain solution to your mix.

 

we r using 3% fount, should we go up to say 5%?

 

Give that mix a try and take a reading with the conductivity meter.

 

Hello! increasing wetting your product, you will be too acidic and have trouble drying! the problem is with agfa if with the azura it was good, the TS cause problems? I'm interested very much, how to behave because the TS early July we will work with!

 

Thanx for the tip , while going through my conductivity and alcohol measurments i realised why codutivity was so low.. It was our dodgy hydrometer it was off by 6% in effect our alcohol was 16% intead of 10%.
Didnt know whether to laugh or cry.
I borowed another hydrometer and after re-mixing properly conductivity shot up to 1300.
Just wondering if running alcohol at 16% could have contributed to image desensitisation on long runs?

 

agfa plates

running the same plates oh a heid 6/c 72 no alcohol with conductivity @ 1650 to start. dumping water @ 2500ppm we had similar problems until i adjusted tempeture of fountain solution up to 55f. colder is not better!!! also had much better success when i switched over from a crowned water pan roller to a roller with no crown. on a half sized press you can get away with no crown
good luck

 

Gazman,

Yes, too much alcohol will kinda act like a solvent and will "wash away" the ink.

 

We have problems with the Lap-v silver plate from agfa and we also tested with Kodak Thermal news plates and there was no blinding or what so ever. The blinding started at 20.000 with agfa plates and they told us it was mechanical wear on the press. ....uhmmmmm it occured on a 9 year old press and a 9 month old press.....
Now we narrowed it down to plate thickness. When we have blinding the plates are 0.273mm thick. Since some weeks we have 0.279-0.283mm plates and there is no blinding or what so ever.
So Agfa's attitude towords customers is below level all over the world and not only in the Netherlands......

 

ive noticed that the agfa azura plates come delivered with inconsistent grain directions. ive found that the long grain plates tend to offer a greater latitude when it comes to water control

 

Thanx for all the info, it seems that i am being called into yet another meeting with agfa where they are going to inform me yet again that we are the only ones in the WORLD with problems with azura.

 

Fine cracks in the rollers open up when they are warm. If the press is washed up with surfactant (detergents) they will soak into the rollers slowly leaking out and causing either non-inking, chemical tinting or both. Wash with plenty of warm water and always use washing up chemicals as prescribed on the tin. If they suggest diluting with water do so.
Salesmen will often suggest using them neat. Good for business.
It seems you have given your press a good cleaning and failed to remove something.

I hope this helps.

 

Same experience with Fuji Ecomaxx-T

Gazman,

It's not necessarily just the Agfa plates...

We are having same problems as you since switching from film-based workflow to CTP with Ecomaxx-T plates. At first we were using sub with these, changed everything at press, all solutions and concentrations and temps, went back to alcohol only at 7% and tried for 7 months now to make this work but have intermittent problems with blinding at rollup, at 10k, at 20k, on various units.

We believe it is mostly paper related, calcium, but we never had this on our old film-based analog plates. We are probably going to be switching to Fuji's LHPJ plate but they tell us it has the exact same "enhanced, multi-grain" that the Ecomaxx does and may not help our blinding problem at all. They said the old analog plate FNS-S was double-grained and as such would probably be better with calcium problem than the finer grain of the Ecomaxx. They also said that the 7% may be too much because its making the plate wetter and these are made to work better with sub.

We found our pressmen weren't calcium washing often enough, that when they did they were rinsing afterwards with less than a quart of water for all 6 units combined which Fuji tells us isn't near enough to get any loosened calcium off the rollers. We also have blamed them for getting wash on the plates. We were told by Fuji to use the Febo first as it does no good to try and de-calcify glazed rollers. And yes, our paper comes from Korea.

Anyway, we have tried many things, blame has been passed around on everyone at different times, but the bottom line is, it's time to do something different, this is not working for us. What are you doing now? Did you find a solution? I found this thread trying to research Azura vs. the LHPJ which we're probably going to pick one next week, your problems with the Azura so similar to ours on the Ecomaxx is not encouraging for the Agfa solution, for us anyway.

 

Please do not rule out the plate processor. We have had plates going blind as well as scumming, we tried different plates etc etc...

Check to see that the plate makers are changing their chemistry often, they should record when to do so, time date and so on...

We now change our chemistry every 800 plates.

 

It sounds to me like some sort of gum or wash is drying on your plates and blinding them. What do your roller stripes look like?