prints inconsistent Heidelberg windmill

Hello,

Recently my windmill starting printing inconsistently. I will have three good prints and then one where the inking is too light. Then 5 prints good prints and then another too light.
I have adjusted the roller height
I have cleaned the rails
I tried spraying the rails lightly with adhesive ( after reading a post here)
I have changed the packaging and tympan paper
Anybody have any other ideas as to what is happening?

Thank you

image: IMG_3834.JPG

IMG_3834.JPG

image: IMG_3833.JPG

IMG_3833.JPG

image: IMG_3832.JPG

IMG_3832.JPG

Log in to reply   8 replies so far

if you happen to have an empty core, you could pull each roller, put the empty in, and run an individual roller to see if a given roller is deficient. sounds to me like on certain passes, your rollers are at the correct height. then, on others, they get in time with each other and don’t ink the forme properly.

I have some new rollers. I will give it a try! Thank you

Inspect the shear collar. It might be cracked.

The rollers are set too high above the form. Lower them slightly.

Michael

Sounds to me like you’ve developed some flat spots. Be careful of where your letting them rest. Also if your washing your press up with anything other than press wash it could be stripping the integrity from the rollers. Press wash has additives that help keep rollers healthy. Helps maintain their roundness and ink receptivity.
Press wash would be available thru your nearest paper store.

Having the same issue; four good prints and then a light one. I’ve been adjusting the roller higher and higher until it’s just above the type, and then it starts to get lighter, so I have to adjust it down until it inks up fully. Either way, my end result is either salty or muddy impressions. One odd thing I notice is that when I get it close to even, the roller heights are really different on left side versus right side. My trucks are new, rollers are recovered new.
I will inspect my shear collar and see if it’s ok. The previous pressman did lock up the press a year ago or so.
Is my ink too loose from the ink company we had mix it?
After adjusting roller height, do they settle a bit and continue to change over 10 impressions?
I use press wash and a roller conditioner liquid, so nothing crazy I would think.

Have you checked for roller slippage? Clean off the tracks, and wipe the roller trucks with type wash. Dry completely. I sometimes will add a light dusting of corn starch on the tracks. I just finished an order where the ink sprayed a light coating on the tracks-I had to clean them daily.

Gray ink can be fun since it lack good body and tack. I hate rubber base inks but that is just me. I use zipset soy base inks. I like the tack and cleanup. Hand wipe the rollers and drum. Each day when I start to print the first thing I do is lockout the rollers and manually clean the drum. Overnight small amount of oil can can drip onto the drum edges and then mix with your ink when you startup. You want any oil, blanket, roller wash out of the press. Your roller track heights should be closer to the same. Pull the chase out and look for any sort of debris which might be changing your base height. I don’t use my skeleton chases for printing. The heavier frame of the regular chase works better for me. Inspect the press to make sure not bits of crap are in the case lockup area. Take the chase to your lock up stone, I use my cutter bed, to get a good flat base. Release the coins and while holding the base and chase in place tighten the coins one by one a little at a time while using your other hand to keep the base and chase flat. Lock up using pressure from both top and side of chase frame. When you are done your lockup should be flat and not rock at all on the stone. You should be able to run your hand along the chase back onto the lockup furniture and the edge transition should smooth. If they are overtightened you may be twisting the chase a little and it may feel strange or bind when you place it into the press. Now you print fame should be flat. Remember to lock the top chase holding screw in the chase clamp. If the base was not flat you are adjusting the roller tracks to compensate and that my be causing the inking issue. Since the image looks lighter at the bottom you may want to back off the pressure but add more packing to even it up. It also does not hurt to use new packing if you are having a problem. Since adding more pressure tilts top in it may explain the inconsistent prints as an occasional lack of impression between prints.