Di52 Whats at play here???

Disappointed

Well-known member
Long story I'm afraid...

We have had a Presstek Di52(waterless) for the last 8 years, started out with issues (hence my user name!) It came with Toyo inks as they were recommended for it, but the colours were useless and no good for euro/ISO colour printing, being a Japanese ink set.

Soon after, we discovered an ink by Hostman Steinberg, these were perfect, ran lovely and the colours were 100%, we stuck with these for 4 years or so. Then they started tinting for unknown reasons, press was checked Ok, only things to blame were ink and plates - no response on either so we had no choice but to ditch the ink.

We then went to VanSon inks and found they had one that worked and looked ok, stuck with that for a couple of years, then that started failing, IIRC it started picking badly and needed constant reducers adding - time to bail on it.

Then we tried a set by Classic colours - no tech support and they have gone now so are out of the running.

Next we got talking to Presstek, and found they were working on a special Di mix with VanSon so I put my name down for testing it - this took some 6-8months but we finally got a good mix - nice colours, stable, duct fresh etc. VanSon made a batch for Presstek and sent it over. That ran very well for about 6-7months then I started noticing picking on tints etc, black was first so I added reducers and it worked, a few months later the cyan and magenta started picking, reducers don't work so well on the colours but it helped. Then after about a year it was so bad I couldn't run a job - on uncoated stocks it was ripping the surface off the sheet literally.

Time to ditch the mix.

The ONLY waterless ink left is Toyo again, by now we were so fed up we decided to forego accurate colour for the sake of getting jobs done - not an easy choice. We managed a few jobs by tweaking the SID's wildly on the colours to try and match our preferred euro flavour output.

Until that is, we tried printing on uncoated stock - all we could get is a patchy mottled effect. Engineer verified the pressures are good, so we fitted new forme rollers - no change. The only way we could get a result is to run the cylinder pressure massively over normal pressure setting - this is something I hate and have never done in 30+ years of print, it wrecks blankets and buggers bearings i.e. it's a botch.

So here we are, there are no other inks we can try, trying other inks is very expensive as to go further than a basic test means recalibrating the RIP to give sensible output for that ink set - this takes around a day each for coated and uncoated stocks plus unknown sets of plates and piles of paper. This is something that must be done but you surely don't want to be doing it too often.

In desperation I tried the Hostman steinberg ink again, it tinted and still printed patchy.
I tried the Van-son mix again - still patchy print.

Now, I am out of suggestions, the patchy effect suggests ink too tacky but a thinner ink prints as bad. Rollers made no difference, new blankets made no difference, hard or soft packings - no change, temperature change - nada. I tried a very smooth quality of uncoated stock and it was just as bad - patchy. Serious over pressure works but we would never have run like that before so why do we have to now??

Basically I have gone from being disappointed to very happy to ecstatic back to being very disappointed with waterless print over the 8 year period. At present I cant print a sheet and have not for a couple of weeks now, not very well anyway. Luckily we are in-plant and can handle an amount of supply difficulty but if we had been a commercial shop then we would likely be closed down by now.

The press has only done 23m impressions so its barely run in yet and has been very well cared for. Back in the good days, this machine was perfect - 20 sheet make-readies to colour, 15 minute turnaround, 10 minute cleanup at the end of the day, 1 sheet size change, but now??????
 
Last edited:

Disappointed

Well-known member
We have, so far they drawn a blank.

We have managed to print some jobs now, but on the uncoated stock we have to clamp down hard on the impression setting. It works fine on uncoated though which points to ink I think - too tacky or very poor trapping.
 

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