Sword Excel Plate has lines in non-image area that print....

[jlind]

I hear that this happens occasionally when the developer needs replenished. However, this time, it happened after 400 plates instead of 800 plates.
It was a flier that has a lot of white space. When you looked with a loupe, there they were, like a line of 10 micron stochastic dots. Seems like it was just the cyan plate. If it was more than one color, man, that was good register.
Has anyone dealt with this before?
Prepress realized there were dozens of plates already imaged. These had to be run through the processor again, with the gum from the processed plates contaminating the chemistry, so it had to be dumped.
Any ideas how to head this off at the pass?
John Lind
Cranberry Township, PA
724-776-4718

[seejay]

john,

what device are you using to image the plates?

I have experienced something very similar before with kodak plates - in our case, the imagesetter was marginally out of tolerance and wasn't exposing the background away. The lines weren't visible using a normal loupe and only showed on press due to .... perfect register of all 4 colours. Our initial take was similar - only in the cyan, but when view with a 20x magnifier they were evident on all 4 plates.

Reprocessing the plates was not an option in our case, as this ended up overdeveloping the plates causing colour issues on press. We ended up bumping up the laser power to fix the issue. An remaking lots!! of plates.

Edited by: seejay on Feb 28, 2008 9:10 PM

[Point918]

John;

I'll second seejay's response.
Our Trendsetter's laser was slightly out of alignment when relatively new and our Sword plates showed lines like the one's you describe. Field Service Tech made some adjustments and the problem has not resurfaced in nearly a year.
On another note I was NOT aware that gummed plates run back through the processor had any affect on the developer chemistry or the could overdevelop a thermal plate. I'll have to bounce that off our Kodak Plate tech.

Don Evans

[jlind]

It's a Lotem 400V, last adjusted on Feb 7, 2008.
How long should a laser such as this stay "tuned"?
What makes a laser change in power and focus? Age? Something used up? Loss of atoms?
Can you see this stuff easier with a plate control target? It seems to be in some areas of the plate more than others.
That was good feed back, I know someone who really appreciates it.
John Lind
Cranberry Township, PA
724-776-4718

[Paultheprinter]

Hello,

cant add much except we had this issue with kodak plates when our CTP unit was installed. Im sure they called them REL lines. Same fix remake plates.

Paul

[PeterA]

John
As Kodak if its the temp around the laser head
Peter

[heatset]

The symptoms you are describing indicate a lack of energy being transferred to the plate by the laser. We found that running a power sweep on the platesetter every month and adjusting as necessary totally eliminated this problem. This is in a higher volume shop running 8000 - 10000 plates a month.

[paulrfrancis]

We're running a Lotem 800 with an IGP Thermaline 120 processor and we had lines that appeared on all 3 of our webs at the same time. We dropped the dev and noticed that a guide roller gear, that sits in the dev, was broken, so roller wasn't spinning, so we placed one on order and changed the dev. The lines went, but we were only getting half of the dev life. We got Kodak in, they changed laser settings, got new batches of plates, cleaned processor, but nothing really conclusive. Then we got our new roller which was put in at the same time as all this was going on, and, bingo, the lines went and we haven't seen them since. People said it was coincidence, but I don't know.
We saw near exact lines again once and it turned out to be the paper, which the printer got rid of by turning the reel over.

[Joe]

We just went through this. You will get these lines in 2 different circumstances. The first is if you are not getting the proper circulation in your processor due to a dirty filter. The second is if the scrub rollers need replaced. If you can send the plates back through the processor to get rid of the lines it is not the CTP imaging unit. It is a processor problem. Or so the tech tells me and proved to me.

The tech also told me that Sword plates are a very dirty plate and cause more plate dust than most other plates and turning up the laser power makes it even worse. I can vouch for the plate dust. We just had to do a complete cleanup in our plate room and what a mess it was.

[rakam]

Just ran into what may be a similar problem...had 2 boxes of plates that had an upcurl real bad. After finishing the first box, we set it aside and got into one of the 8 other boxes that had a different lot number. Right away we could tell the plates were not curled, that was good. As soon as the first plate was done imaging and shot out, I saw all this "dust" on the plate. It also was like in bands or stripes about 2" wide. These are 60" plates and the bands went clear across the plate, the bands went in the direction around the drum, not the 60" way. Called our Kodak tech people and he and a field engineer came out. Said there is a problem with the ablation and that we will need to change chemistry more often. Since chemistry was at cycle end, we changed it. Output a plate, same pattern after ejecting from platesetter, and SAME PROBLEM after being processed. The dots do not appear to be affected. It is EXTRA image. As one post mentioned, it looks like a stochatic type pattern. We print packaging, run around the clock 7 days a week...so far, we haven't had any real critical color jobs that it would be noticed on, but in the non image area it is very noticeable.

So, Kodak's reply is need to change chemistry more often. However, fresh chemistry did not fix the problem. NOW WHAT??? Tech coming in tomorrow, Monday, to see if lessening exposure will help...have my doubts. They also say they have no plates to replace these and thus cannot recall them. That seems pretty odd.

My understanding is these plates are being manufactured in Georgia now. A

Anybody else seeing this problem of late....

Rick