Toning on Heidelberg DI Classic - 3rd unit!

[JohnT]

HELP!
We have a DI Classic that we have had ongoing issues with toning in the 3rd unit.
Typically we run Magenta in the third unit. In trying to combat this issue we have replaced the rollers, rest roller pressures to the plate, changed ink brands, added stop tone to the ink and have the room where the press is at temperature controlled.
Has anyone else had these issues?? What did you do to remedy the issue?

Also we tried different colors in the unit and still have the issue.

 

[Al Ferrari]

How about putting aside the assumption that it has to do with the ink train on that unit, and focus instead on the water system on that unit. It may be contaminated in some way. Swap the water recirculating units with the Cyan unit, disconnecting the hoses as close to the water pan as possible, and thoroughly clean only the water rollers and the pan, and only on the problem unit.

Does that switch the problem to the cyan unit?

Al Ferrari

EDIT: It just occurred to me this may be a waterless press. If so, how about contamination of the ink train? (oil dripping from a cross bar?)

 

[JohnT]

The DI is a waterless press.

 

[stu]

Air in the cooling system, or dirty blanket cleaning units gave me toning problems in the past

 

[nhprinter]

Toning on the DI is almost always caused by the rollers getting too warm or by contaminated ink.

To go along with what Stu said....if you feel that the temperature in that unit is the same as the others and you don't have any air in your cooling lines... you might want to clean that blanket by hand rather than use the auto blanket washers and see if that helps. (it's the easiest one to clean by hand at least) You could also lower the temp in the chiller when you have the problem and see if it goes away.

Good luck,
Dave

 

[inkedup]

I agree with nhprinter and will add this. If you have access to a Infrared Thermometer check the roller temps and the blanket cylinder temps as well in the toning unit and one other that is not toning. Your problem could be the chillers not ink.

 

[JohnT]

Roller Temps

Roller Temps

We do have an infrared thermometer. The Rollers where the coolant is running through them is running at 68 degrees F, the rollers themselves in the other part of ink train end up at 74 degrees F.

Our chiller has digital gauge and won't allow us to lower the temperature past where we are at now. It is accurate to the temperatures we are reading...

Any ideas, anyone?

Does anyone know of a DI forum?:

 

[rbailleu]

try adding anti toning/ tac increasing oil to magenta I thought it was a toyo product. you could try medium tac

 

[Cornishpastythighs]

Stupid question I know but have you contacted Heidelberg for help

 

[Happyprinter]

We have a QMDI Plus and recently changed the rollers out. Before changing, we have never had a toning issue. When we started our first run we had severe toning on our yellow unit. We checked temperature, blanket etc.. We retimed the machine, but nothing would get rid of it. Finally, we backed the 3rd form all the way off and set #2 at 1.5 and #1 at 1.5. Also check and make sure that #3 is seated correctly in it's saddle. This was the only way we were able to eliminate the toning issue. Also, make sure your distributors are CLEAN and not glazed. Hope this helps.

 

[Happyprinter]

Dipressforums.com

 

[maynard105]

i think happyprinter is pointing you in the right direction....also be sure your forms are shimmed tight in the journals.....DI printing is quite a journey eh?
mikem

 

[mrheidelberg]

Printing Press and Color Printing forum has a good DI section.

 

[teeroy]

I f you tried other colors we know this is not the problem so you either have a roller that is oscillating to much or you are over packed in that unit and it is squeezing the water off of the plate .

 

[JohnT]

Solution Found for Toning

Solution Found for Toning

The solution was found. We had our Heidelberg mechanic come in and he found that in the pressure between the FORM to OSCILLATOR roller pressure was to light. The pressure stripe is suppose to be 4 mil and the stripe to the plate at 2 mil.

Toning completely gone! Yeah!! Go Heidelberg!

 

[Deleted member 16349]

The solution was found. We had our Heidelberg mechanic come in and he found that in the pressure between the FORM to OSCILLATOR roller pressure was to light. The pressure stripe is suppose to be 4 mil and the stripe to the plate at 2 mil.

Toning completely gone! Yeah!! Go Heidelberg!

Great news JohnT. By the way, did the mechanic say why the light pressure caused the toning. Just curious. Thanks.

 

[JohnT]

Cause for

Cause for

The mechanic thought the form, once it had the film of ink on it was being driven by light friction and may have been skidding. The form had 4 mil stripe to the plate but was just too light of pressure to the oscillator. The form was mainly being driven then by the plate cylinder, thus causing it to skid or bounce or tone.
The interesting thing is that the "tone" mark was always in the same spot, about 3/4 the way down the press sheet on the gateway platform side (non operator).

 

[Cornishpastythighs]

Its nice to see someone who actually posts the solution of a problem, many times people post issues and get whacks of people replying with help and you never hear from them again. Good work JohnT

 

[sevag k]

ive had plenty of toning issues also. what helps also JohnT is verifying the timing of your osalators!!!

 

[PricelineNegotiator]

Dank necropost, bro.