Heidelberg Windmill Inking Problem/Ghosting

Hey fellow printers,

I know there are several discussions on here that deal with ink distribution issues and ghosting but I am having an issue that doesn’t look like the type of ghosting I have seen before.

I am getting a very defined shift in color at the same spot in my chase no matter where I move my polymer plate to. I am printing on a 10x15 Heidelberg Windmill. I have checked the packing, the press bed, the boxcar base, used several different plates, checked roller height, used tack reducers and made sure there were no cracks in the pressure ring in the back of the press and I am getting the same result.

I am attaching a few pictures for context of some test prints I did with a large cover area.

I started noticing the issue when the temperature dropped recently as we got into the winter months so I am curious if it’s just the cold in my work area getting to the plates, ink and rollers. I have a rider roller on the way that I have been told will help some, not only with coverage but heating up the rollers with more friction as well.

Any thoughts would be appreciated!

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Are the rails and trucks clean and free of oil?

Also, are the bearings in the trucks spinning freely?

I see ink on the base, so I assume the Form rollers are not setup right, The Press has a fine balance between packing and pressure to get it right, if the Form rollers are running to low, you force them to place more ink and hence they run out and lay down lighter after their circumfence is exhausted.

To me, it appears the ink on the base is from wiping off the plate between tests, not roller contact.

The picture with the print next to the chase, I presume indicates the orientation of the paper and result, showing that the topmost area of the form where the rollers contact first is inking poorly. If the trucks or rails are dirty or slick, the rollers might skid when they first contact the plate; smearing the ink, rather than applying it while rolling.

Another member recently had an issue with the roller bearings being out of position, causing the arms to retract improperly… I suppose bearing issues or arm issues deserve consideration too.

AnonyMouse you are correct, ink on the base is me just being messy during all the test runs and not thourghly cleaning it off each time, I will look closer into the trucks and rails and make sure there is not oil or anything else that could be causing slippage. I will triple check roller height as well just to rule that out completely.

Thanks for the help everyone I really appreciate it. Just kinda frustrated because I’m getting pretty good coverage other than that one spot. I did another test tonight with a plate with artwork that was so uniform and rectangular and looked pretty nice, I didn’t seem to notice the distinct fade in color like the other runs.

Let me know if you think of anything else and I will keep troubleshooting.

Did you check to make sure that you are distributing the ink evenly with the chrome roller in the fountain? check the adjustable screws and make sure the form roller has correct pressure against the cylinder. I would start there, next check roller height. Also check the actual form rollers, they may be worn on one side. You can try and flip them around and see if that works also. Good luck!

The more I look at your pics, the more I think it is just a packing problem. Make sure that you have even packing right across, also check adhesive on the plate. You should be able to fix this with a little extra packing on the low spot.

If you clean the press and don’t find any oil or contaminants or reasons why roller slippage might be causing the issue, it could be the tack of the ink. In that case, I would blame the cold and say you could stand to add a modifier.
ITA (Ink Transfer Agent) or Setswell compound (both are separate products but the same basic ‘thing’) will help the ink loosen and transfer a little more easily. You can use these modifiers wether using rubber or oil base ink.

In the case you’ve never used them before- use them conservatively, a small ‘flick’ that is not even a tenth of a gram per 100 grams of ink is more than enough. Your ink should be just a little easier to work around with a knife essentially, and believe me- a little goes a loooooooong way.

Good luck.