Presstek 52Di info sought...

[Disappointed]

Does anyone here know if the plate cleaning wipes used in the imaging system on the 52Di contain silicon oil or not??

Also is anyone out there running this press with Stehlin-Hostag "Reflecta Dry" inks???


Thanks

 

[Jonelle]

Disappointed,

If you are referring to part # MYY52005, plate cleaning towels for the Presstek 52DI, we have verified that they do not contain any silicon oil.

Jonelle - Presstek Marketing

 

[Disappointed]

Disappointed,

If you are referring to part # MYY52005, plate cleaning towels for the Presstek 52DI, we have verified that they do not contain any silicon oil.

Jonelle - Presstek Marketing

Excellent, thanks for the reply.

Now for the inks question, it seems i am the only person running this ink set

Dave

 

[Jonelle]

I have polled our staff and no one has indicated that our DI customers are using Stehlin-Hostag inks. For the DI presses, our technicians prefer the Toyo waterless inks and our customers tend to be very happy using them also.

Jonelle - Presstek Marketing

 

[Disappointed]

Many thanks for the reply, we found that with the Toyo set, we would have to adjust the chiller to a high temperature in the morning and then lower it throughout the day, when cold the black picked very badly and when hot the cyan and magenta toned very badly. There was no happy medium and the press could not adjust the temperature itself.

The reason i am asking all these spurious questions is that we have used the Huber/Stehlin Hostag inks for some time now and have found them excellent all day at a fixed temperature but the last few months we are getting toning again but only when we start a new job never during a run.

We are not sure if it is ink or plates or something else but it only ever occurs when we make a new set of plates and only does it when warmed up. Normal toning stays there once it starts but this goes away eventually. It is very odd and is causing a lot of head scratching. Our Presstek engineers and support dept. are also baffled.

 

[mutti8000]

We have tried many different brands of ink and I will access Toyo as number 1 for waterless DI with Van Son coming in as a close second. Under normal circumstances it is almost impossible to get these colors to tone.
I would check every roller stripe in every unit (not just form to oscillating rollers) make sure they are 100% as described in your manual. Next up I would check the temp of the water cooled rollers to make sure it's in line with the temperature on the cooler. Check the temperature at startup, after 500 sheets and when toning. (could be the temperature sensor in the cooler needs calibrating) Another theory would be small drips or a small leak of roller cleaning fluid. This would show up as toning that disappears again, and the come again with the next drop of cleaning fluid.

 

[Disappointed]

Thanks mutti,
The machine is very well maintained, has had two Presstek services in the last 6 months and all mechanical aspects are 100% by the book. All ink units were recently stripped cleaned and rebuilt, some with new forme rollers, the chiller unit was serviced 6 months ago, roller temps are within 1 degree of indicated temp on chiller.

It is not the blanket wash as it does it if we hand wash them. It is not the plate clean as it does it even if we hand wipe the plates before running. It is definately triggered by heat as the first two runs of the day are fine and on colour in 20-50 sheets. If we mak one long run of 25,000 then we get no toning on the run at any speed.

The fault only appears when we start running a new set of plates. I can stop it 100% by putting two or three drips of silicon oil on the rollers before running, instant fix. The big question is why and why only recently.

I can add that we are in a temperature controlled room at 21c and it never goes above this. There has been a fault acknowledged by Presstek regarding the plates a short while ago and this is whats making me think things are not quite right with them still. This fault only affected the first 5-6 plates on the rolls though.

By the way, with the Toyo inks, do you find you have to adjust the temperature?

 

[mutti8000]

With the Toyo ink we run our cooler at a fixed setting 23 degrees celcius, in a non climate controlled enviroment (up till 28 degrees celcius in the summer time) we NEVER get toning. We run the cooler rather high to avoid picking.

If the error dosen't show up on the longer runs, then my first guess would be that it is not heat releated. Have you had a good look at the plates after imaging? I suspect it to be very film of machine oil or grease covering the plate. (try to gently clean the plate with a cotton bud and alcohol) This oil film will only show up after plate imaging as the cylinders spins alot faster during imaging!
In theory it could also be bad bearings heating up the plate cylinders during imaging. Try to measure the surface temp of the platecylinder before and then again during the toning! (a little bit unlikely 2 bearings going bad at the same time unless the machine had a major crash at some point?

You had this error before the form rollers was changed?

 

[Disappointed]

Yes we had the problem before roller change, I was hoping it might help.

I will try an alcohol wipe before a run this week.

No crashes, never even had a wrap-up, plate and blanket cylinders do get warm, will measure them as well.

I recall we used 23c when we had toyo too, it was the recommended setting back then.

Thanks

 

[Prime12]

I too have problems with the 52DI. Ink piling on the plate, offsetting on uncoated stock even with heavy spray and IR running. Toyo EX ink which is fast dry, I can run 1000 sheets and back up right away with no marking. Toyo MZ offsets worse and the piling is the same. I found an ink that look great, runs great but soon as the temp start to rise past 21 it wants to tone. Trying to get chiller fixed to control temp better. This ink lays down way nicer then Toyo. I'm trying to get them to alter the yellow for me to help fight the toning. Most of my work is larger quantities 20M plus so the machine does not get a rest to cool down on its own. Does any one else us theirs for long runs? How does it perform?
Thanks

 

[Disappointed]

I too have problems with the 52DI. Ink piling on the plate, offsetting on uncoated stock even with heavy spray and IR running. Toyo EX ink which is fast dry, I can run 1000 sheets and back up right away with no marking. Toyo MZ offsets worse and the piling is the same. I found an ink that look great, runs great but soon as the temp start to rise past 21 it wants to tone. Trying to get chiller fixed to control temp better. This ink lays down way nicer then Toyo. I'm trying to get them to alter the yellow for me to help fight the toning. Most of my work is larger quantities 20M plus so the machine does not get a rest to cool down on its own. Does any one else us theirs for long runs? How does it perform?
Thanks

Are you saying 20M as in 20 million?? If so i would have thought that sort of job to be far better suited the B1 press guys.

I have not heard of Toyo Ex, but i recall that the Toyo LZ/MZ were too fast drying on the rollers and also had serious problems with paper picking and transferring to the rollers and duct. I hear some use LZ black and MZ Cyan, Magenta and yellow but its not very good as the LZ has a lower pigment level and you lose contrast in pictures etc. Set-off was also a major headache.

Get some silicon oil from your ink suppliers and next time you get toning, put 4 small drips on the rollers that are toning and see what happens, i have learnt that this is a sure-fire tool against toning but it does have drawbacks if you need to foil over-print or varnish/laminate etc.

I too am having difficulty with temperature increase and get toning but only at the start of the run. We are testing different ink mixes at present but getting the ink industry to play ball is not easy, just not interested it seems.

The ideal system would have chilled plate cylinders as that is the critical point in a waterless press, not available though.

 

[mutti8000]

The machine should be able to run 24/7 with no toning issue!
Please double check that there is no sideways freeplay in the form rollers. The form rollers should be shimmed to an exact fit, the slightest oscilating movement and the roller and plate will heat up and begin to tone.

Also check that you are running the machine with the heat shield down (below unit4) if not the machine will eventually heat up, when using the IR dryier.

 

[Disappointed]

Thanks mutti,

The rollers were recently changed and properly set for no side play so I'm confident that's not the problem.

Interesting you mention the heat shield, we were taught by the trainer to leave it up. Anyways, I ran for a whole day with the IR off and it still toned at the start of runs in the afternoon, not as bad but still.

Don't forget this is not normal toning, my toning only ever occurs at the start of a run on fresh plates, never after stopping during a run or at any other time.

I measured the plate surface yesterday, when I started at 8am it was 14c and when I finished at 2.30 it was 28c so there is a large increase but I have no comparison so this could be normal??? Toning started at around 22c but cleared within 150 sheets.

 

[Disappointed]

Well, Friday I had a long, fast running day, eight runs of 8000s at 8500/hour, plate cylinder started off at 15c and ended up at 35c. Plate toning during start-up happened after the plate reached 23c and got progressively worse as the temperature rose, But only ever at start-of-run never during the run, even after a ten minute stoppage.

My only weapon was to keep adding silicon oil to the rollers.

I have been trying to get the technical guy from the ink makers to visit for two weeks now but keep getting fobbed off with excuses, today's meeting was again cancelled.

I am at a loss now as to what direction to go in, plates, press, ink?????

Why has it only started in the last six months??

 

[mutti8000]

Good you tried turning the IR drier off, so thats not you problem. The next time your instructor tells you to leave the heat shield up, ask him why it's there!
If the toning is only comming at start-up of a new plate set, i would suspect some kind of contamination of the plate material.
Did you try wiping the plates with alcohol after the automatic cleaning, prior to the test prints?
How do you store your clean-up rools? Manufactuerer and manufactoring data?

 

[Disappointed]

HI mutti, the instructor will not be back , we have been running for about four years now

I tried wiping the new plates with alcohol, no difference, there was no visible contamination before i wiped and wipe was clean after.

The clean-up rolls are stored as suggested - on a level surface in a cupboard and i even rotate them if i remember when getting other supplies out.

However, if i wipe the clean plate carefully with a pad and silicon oil, no toning appears at all, the image takes longer to ink up but no toning occurs, this is what leads me to suspect the plates but if it were them then others would have issues too.

I'm not getting very far with the ink people either, it seems the days of house-visits are long gone now.

 

[Disappointed]

Ink guy has finally been, taken samples away.

He feels that because it only occurs at the start of a new set of plates, it is pointing strongly to the plates themselves or the development system on the press.

Back to Presstek now.......