Windmill inking issues
I’m having some trouble with the inking on my windmill for this particular project. I can’t attach photos for some reason, so here’s a link to the images:
http://voteforletterpress.com/wp-content/uploads/2015/12/just.jpg
http://voteforletterpress.com/wp-content/uploads/2015/12/tel.jpg
Two problems:
1) The inking is light and somewhat spotty (particularly on the larger type, like the JUST image). If I load up the ink, it just ends up spreading too much and the small type looks blobby. Definitely not good. How can I get better ink coverage? I’m using a fair amount of impression, so I’m not just kissing the sheet. The paper is Colorplan Frost White 220 lb. cardstock. Would it help if the paper were warmer? It’s about 60°F in my studio with humidity about 50%. I’m also considering putting the paper in a smaller room and running a humidifier overnight to add a little moisture to the sheets. My only concern with that is that the greater humidity might cause registration issues.
2) More importantly, there is an accumulation of ink on the shoulders of the type at the top and bottom of the plate. You can really see it on TEL. That would suggest to me that the rollers are too low, so I raised them in small increments to see if it would improve. Even at much higher settings, where it would barely ink the plate, there was still ink accumulation on the shoulders. I tried adding some photopolymer strips to both sides of the plate to give the rollers some bearers but it didn’t really help. I also added some tacky spray to the rails in case the rollers were slurring and sliding, but no change. Normally I wouldn’t worry too much about it, but it’s smearing when the next sheet drops down and ruining my prints, so it’s obviously a lot of ink. Why is it doing this? This is not a common thing I experience, and it hasn’t done it for the previous plates on this job (including the same color). I’m using a custom ink from a local manufacturer that I’ve used many times before with success. The ink is low-tack as previous inks from Van Son caused a ton of fiber picking on this sheet (I ran this job about 8 months ago with different colors.)
Any help is appreciated!
with mixed large and small type on polymer plates I have run some jobs in two passes. One pass for the larger solids where I skip feed for more coverage and then a single swipe for the smaller type. Just make sure you do not over/under ink one of the runs. Also have a good look at your plate, you may have excess polymer along the bottom.
Good luck!
Ian
I looked at it and didn’t see any excess or plate flaws. My platemaker has always produced good plates. The small type isn’t small enough to warrant splitting the plates. I did that for the reverse side of the card that has a big headline and then smaller text section. I’ve printed this card before and this plate ran fine, but I ran it in the spring when it was warmer, and I’m wondering if that’s part of the problem.
If your roller diameter isn’t really close to but slightly larger than your trucks, in other words if the rollers are significantly larger, you are probably getting slurring from the roller surface traveling faster than the truck surface and wiping some ink off on the bottom edge of the image. I believe the best size difference is that the rollers are not more than 1/16 inch larger in diameter (not radius) than the trucks. That allows about 1/32 inch of compression of the rollers for ink transfer max. Less is better.
Bob
I’ll double-check but I think they are pretty close to a match. Like I said in the original post, I haven’t had this problem before, where there’s so much accumulation of ink on the shoulders of the type.
just from the pictures, Looks like ink that has a lot of white in it. Maybe even transparent white. Roller pressure to high. Heavy ink.
Also looks like the Ink isn’t milled enough.
It looks like the ink is not transferring well to the image. The rollers could have not been complete dry when you started and has cleaning fluid on rollers and the ink isn’t go on the inking rollers correctly.
If it was me, I would wash the rollers and ink plate and remove all the old ink and make sure the rollers and plate are good and dry before starting with re-inking.
Also, make sure the ink is not dry before placing on the ink plate.
Old stuff ink will not transfer to the rollers correctly. I have found that out myself. Work the ink on a inking plate on a table and make sure it not dry and hard.
I heated up the ink and it was quite loose. It’s also brand new ink. I’m not at the studio today so don’t know the makeup of the ink. It’s Pantone 7706, if that helps. It’s pretty dark greenish blue. I’d be surprised if there’s any white in it.
Theo, when you say roller pressure is too high, is that alleviated by adjusting the rails? Because I’ve done that and the only way to eliminate the shoulder ink is to move the rollers so high that it doesn’t transfer enough ink to the plate.
There appears to be a couple of problems.
You have an ink build up at the top and bottom edges caused by the roller(s) catching the edge .
The roller height or forme height is wrong, rollers too low or forme too high.
Use a pair of calipers and check the rollers are the same diameter. If they are different diameters you won’t be able to set the roller height correctly.
Get a roller gauge and adjust the roller height using the 4 adjusters on the sides of the Heidi.
Get a type high gauge and check the height of your job.
Correcting the heights(s) will solve the ink collection on the edges.
The problem with low tack ink is that it spreads under pressure compared to normal letterpress ink.
I have just had to do 150 sheets of hand made paper double sided. As the paper was not sized there were fibres flying everywhere and I had to wash up 3 times.
There is no problem with registration of dampened paper provided it is kept at the same humidity. Dry paper printing didn’t become common until the late 1800s.
Would warming up the sheets and/or adding more humidity help the ink flow (i.e. resolve some of the speckling)?
I will check all roller heights and diameters. I’m using a boxcar base with KF52 plates, so I’m pretty sure everything is type high. Again, this didn’t happen with the other colors or this particular ink on the reverse side of the sheet. All I can think of that changed is temperature and humidity.
Leave paper as is, you could end up with a curly job at the end as the cellulose re-absorbs water.
Humidity won’t affect the ink, the ink will warm up as you run the Heidi.
The only variable you have altered is the plate.
If the same ink printed ok previously was it on a similar size lettering?
Yes. It was a little spotty as well, so I ran the ink fairly heavy. But I didn’t have the shoulders of ink buildup, so I’m just not sure what’s changed.
It may be tedious (printing 1500 cards), but I may put this on the Vandercook and see if that does anything. I’m getting a bit desparate as this job should have been done by now.
If one side of the sheet prints well and the other side is a problem, that is related to how the sheet is formed rather than ink/rollers/luck, etc. The felt side of a sheet usually prints easier than the wire side, and with all cotton sheets this difference can be pronounced. Going to the Vandercook with the cylinder rather than a platen may make a noticeable difference.
Most paper is packaged with the felt side up, usually marked as the “print” side. Easy to test if this is the problem—print the same image on both sides of the sheet and look at the results.
I looked up your color and 7706 does indeed call for transparent white. I’ve had similar problems with some of the 7000 series of Pantone Plus colors that I felt were caused by trans white being added to dark (-er) colors. Can you remix using opaque white? Not sure if that would help, but it does give the ink more body sometimes…
My first Reply….just from the pictures, Looks like ink that has a lot of white in it. Maybe even transparent white. Roller pressure to high. Heavy ink.
Also looks like the Ink isn’t milled enough.
Your Question…
Theo, when you say roller pressure is too high, is that alleviated by adjusting the rails? (Yes the rails, but if your more than type high make it type high and go from there.) Because I’ve done that and the only way to eliminate the shoulder ink is to move the rollers so high that it doesn’t transfer enough ink to the plate.
In further…
Transparent Ink runs very different, unless your over printing to obtain other colors. I’d only use opaque white to mix. Usually when one runs Transparent ink, there is a tendency to over ink to obtain the desired darkness. In most cases that won’t happen. There is not enough density. Also if your using a poly plate, some inks are not really a good match, some do not have a good “cling effect”.
I think you will find if you venture further into these types of jobs, you may want to consult your ink supplier and tell them what your using.
Other wise, I never have problems with Braden Stuphin Ink Co. in Cleveland. I use the New Century Line available in 1 pound cans They also have a nice rubber base ink that I use by the 5 gal buckets.
What do I know,
But back in the days than I learned Letterpress as an Apprentice, we learned that than one prints a mixed Form with small and large Type, Make ready comes into play, as the large Type requires more pressure to print clean and solid.
I decided to order new form rollers. The current ones are pretty old and shiny and a little swollen on the ends, so might as well try that.
j
.
All 4 composition/rubber rollers have the same stock and diameter, check the duct roller and distribution roller as well and send the worst two off for re-covering.
The ductor and distribution rollers are new within the last few months. The form rollers are at least 5 years old (that’s when I bought the press), but probably more like 10 as the press hadn’t been used in 5+ years. They’ve managed this far, but I know it’s time. In the meantime, I’ll print small batches on the Vandercook and hope that gets me through it.
All rollers on your press are the same, if your duct and dist.. rollers are new, use them as forme rollers, that way you can getaway with out spending big money. I ran Heidi. platens for many years commercially
Unfortunately, the new ductor/distribution roller cores are a different diameter from the form roller bearings, so I can’t just swap them. I definitely would have done that if I could.
This is one of the often made mistakes made especially by those new to operating Heidelbergs. The 10x15 original specification calls for roller bearings made for a 9.5MM core diameter, and the less expensive replacement roller made by one US manufacturer and sold by numerous dealers are made for 10MM bearings. These are also made to a harder Durometer. The quick solution is to get a set of the bearings that fit, but it complicates operations with two different bearing diameters in the shop. The runners, or trucks, fit either size, and that adds to the confusion.
One item that every printer should have is caliper of some sort and then know that 9.5MM = .374” and 10MM = .3937” and those not quite 20 thousandths of an inch difference in size are considerable for fitting bearings. In the ink train, it makes no difference because the bearings are not used.