uneven inking on windmill

Hey there,

We’re working on becoming more familiar printing on our windmill before doing real jobs. We’ve successfully diecut on it already. Pretty much everything is going smoothly, except for this. I have slightly too much ink on the top of the type (about 12 lines) which fades down to slighlty too little. The prints seem to be consistent. Though once and a while (during the same run)the fade switches to heavy on bottom and light on top.
I feel stumped, perhaps a rail height issue…? Any help would be great!
Also, I have aligned my polymer plate on our base grid, yet when printed, the text is slightly up hill…we are printing with guides…why would this happen, should i just compensate by moving my plate or is there something else going on?

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Make sure your rollers are set correct and the chase is set correctly in and the screw is tightened, then make sure your rails are clean then put some rosin on the rails to make the roller trucks grip better. It sounds like the rollers are sliding across the type and not rolling.

i agree with cmcgarr, sounds like the rollers are slurring not rolling. Even a little bit of oil on the rails can make the trucks slip a bit. Keep the rails nice and dry. A tap of corn starch can be used in place of rosin, if needed.
As for your text running up hill, you will want to adjust your guides to be even. You will notice a screw and nut assembly on both the right and left ends of the bar that the guides live on. These nuts/screws can be adjusted up and down to even the type. i often make little adjustments here and there even though I have allinged the plate to the base grid. Trying to move the plate itself will be frustrating and time consuming, and alot of guesswork really.
You ought to have a special t-shaped wrench that you can feed a screwdriver through in order to adjust the nut/screw assembly. Try to check in the operators manual for more detail on making this adjustment.
Good luck, hope that helps:)

As you touched on, your rail height may be higher towards the bottom of the form. Loosen the nuts on the 4 adjustments and set them all to the center of the dial as a starting point and go from there.

As a rule of thumb, I always will reset the roller height and guides before every job and start there.

Also, I will twist the cut within the form if I need to before I start adjusting on the guides, it is guess work, but not very time consuming. By twisting the cut and getting it close to straight, I ensure that I will never run out of guide adjustment if something is real crooked.

Perhaps your paper is cut crooked and causing it to print uphill.

Thank you for all of your suggestions. I got the chance to work on this again recently and decided to simplify the test job down to 1 line of text (for letterhead). I am printing on wastenot text weight paper, and I can get it to print close to perfect, but… by the fifth print (which I am assuming is a good judgement of what the rest of the run will look like) my ink coverage isn’t sufficient but it is pushing out at the same time. Also where the ink is laying down it seems mottled.
I have been using a rider roller, though not using the fountain yet as it seems wasteful for the quantity I was working on.
Once again any feedback would be so helpful, thanks much.

First, get a .918 roller setting gauge and check the rollers (both!) at the top and bottom. Also, make sure the rollers match your trucks (place a straightedge across the roller with one end over the truck. It should be flat to the truck (or the truck just slightly smaller). Make sure the rider roller is not mounted up to hard (too much friction against the impression rollers).

Second, I couldn’t tell if you are printing 12 lines of copy, or 12 line wood type. If the latter, you will need to use the fountain or the press will starve in short order (plus your inking will be more consistent and the printing will dry better because the ink has been “worked”). Run the fountain as lean as possible (keys closed up) with the maximum turn on the fountain, then manage your ink by reducing the turn. If you are running only one small line of small type, then the rollers may be riding too hard on the form (smearing the ink off).

Third, it is possible that the press is underpacked, hence with stronger impression at the top than at the bottom, likewise the type could be low. This seems probable with the explanation that the bottom is weak but the top has ink squeezing out. If you have the impression turned up past 2 on the impression handle, I would back that off and add packing.

Of course, these are mere suggestions. Best of luck.