Ryobi 3302 / Crestline washup

[Bacon3302]

The shop I work for just purchased a used Ryobi 3302 with Crestline dampeners. We set it on the floor, cleaned it up a little, inked it up and it printed great. My problem is I can’t get the Crestlines to wash up. I drop the forms onto the plate cylinder like I do with the 3200. The plate cylinder inks up, but the ink from the Crestline doesn’t transfer to the ink roller train. It’s like the ink forms aren’t dropping onto the plate cylinder.

I have the print control lever in the position where both the ink and water forms should be in contact with the plate cylinder.

How do I get the dampeners to wash up?

Thanks for your help

Bacon

 

[Al Ferrari]

Are you still having this problem?

I have that press and dampener combination. Does the problem occur on both units? If only on one, it may be that you are not doing the wash up in "two color mode." That is, the white impression button must be on for both units even though it is not your intention to go on impression. Otherwise, when you put the lever in the 2nd on position for one unit, the other one won't automatically follow. But it should work anyway if you put both units, handles in the same position manually.

Perhaps you are not waiting long enough, or not engaging the washup blade, or not using enough solvent? The problem does not otherwise make sense, since you are able to print, which means that both water and ink forms are making contact with the plate.

More information please.

Al

 

[Bacon3302]

I haven't run the back unit yet so I am just tring to wash one tower, but I have tried putting both units on impression just to see if it would help. It didn't.

I have the washup blade engaged and Im sure I am using enough solvent. The ink train cleans up fine. It seems like the ink forms aren,t dropping unless the press is actually printing.

Is there anything electronic that drops the ink forms when the press senses paper?

 

[Al Ferrari]

You don't by any chance have the "night latches" on, which do hang up the ink forms?

The dropping/lifting of the forms, water or ink, is done by a cam which is mounted on the same shaft as the handle. So, unless the cam is some how not tight to the shaft, the second position of the lever should put both water and ink forms on the plate, Again, if not, then how were you able to "print great?"

Try taking off the handle (one screw) so that you can open the cover door (another screw) to see the action. Replace the handle, and move it from the 0 position, to the first, then the 2nd, and back to first, then back to 0. The machine need not even be running. can you see the form shafts go down, and back up? Perhaps there is some binding going on. Do the same for the other tower. No need to have ink on it, this is just to check out the action for the handle movements. Do both units behave alike?


Al


Edit: I completely blew it when I wrote that the form rollers actuating cam is mounted on the same shaft as the handle. It is actually on a shaft in line with the plate cylinder axis, and is actuated by an arm from the handle shaft. The rest of my post is correct. Sorry if I mislead anyone.

 

[RGPW17100]

You have to go to position three. First position is off, second is just water roller on plate and third positon is water and ink forms on plate. I may be wrong for it has been a long time since I ran one.

 

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Bacon

Bacon

Bacon,

Congrats on the 3302 purchase. Please insure you are washing up with a plate on the cylinder and not washing up on the BARE chrome cylinder. The form stripes could be so light they need the extra thickness of a plate to wash up properly.
The 3302 with Crestline’s is a great machine.

 

[Bacon3302]

Bacon,

Congrats on the 3302 purchase. Please insure you are washing up with a plate on the cylinder and not washing up on the BARE chrome cylinder. The form stripes could be so light they need the extra thickness of a plate to wash up properly.
The 3302 with Crestline’s is a great machine.

That has got to be it. I ran another job on it yesterday and it printed great, but again the crestline wouldn,t wash up. I have been washing up with a bare plate cylinder. It works on the 3200s we have, and the form roller to plate pressures are not excessive on those machines, so i assumed it would work on the 3302. I will check the ink form stripe on the bare cylinder this morning to see if they are even touching. The bare cylinder inks up when I drop the dampners, so I know they're touching.

I should have checked all of the roller pressures before trying to print with the machine anyway, but I was anxious to see it run. We picked it up at auction for $4000.00 and it runs great.

I really appreciate everyones input.

Bacon

 

[Bacon3302]

That was it. The ink form to plate pressures were so light I can't believe it was printing. Once the plate was removed there no contact at all.

I adjusted the rollers and everything washed up fine.

I left the printing industry 15 years ago to go into construction. At that time the only thing I had seen a continious dampening system on was a Jet envelope press. I returned to printing two years ago as residential contruction began it's declining and haven't seen a conventional dampening system yet.

That's just the begining. What the hell happened to the prepress department? No camera, no negs, no stripper, Now it's just some guy sitting at a computer.

Damn this industry changes fast.

Thanks again for your help

Bacon

 

[Al Ferrari]

I have to admit that I too was initially skeptical of Offset Guy's suggestion. (aside from my own botched up second post)

So I spent a little time revisiting high school geometry and came up with the conclusion that your roller stripes need not have been that marginal for the wash up to fail when performed without a plate.

It turns out that a plate thickness of 0.004" to 0.006" is easily enough to explain the observed lack of contact between the ink forms and the bare cylinder if the roller stripes had been set to the plate cylinder with a mounted plate. The attached pdf shows an exaggerated drawing for the deformation of a 2" form roller and what I think is the correct calculation of the depth of deformation on the roller when a stripe of 0.125" is assumed (adjust the calculation with your own numbers).

See Pythagorean theorem - Wikipedia, the free encyclopedia for an explanation of the formula used.

Thanks Offset Guy.

Al

PS The trick to the attachment seems to be to be very patient while in the upload dialog until the "Please wait" message disappears before closing that window.

 

[Deleted member 16349]

I have to admit that I too was initially skeptical of Offset Guy's suggestion. (aside from my own botched up second post)

So I spent a little time revisiting high school geometry and came up with the conclusion that your roller stripes need not have been that marginal for the wash up to fail when performed without a plate.

It turns out that a plate thickness of 0.004" to 0.006" is easily enough to explain the observed lack of contact between the ink forms and the bare cylinder if the roller stripes had been set to the plate cylinder with a mounted plate. The attached pdf shows an exaggerated drawing for the deformation of a 2" form roller and what I think is the correct calculation of the depth of deformation on the roller when a stripe of 0.125" is assumed (adjust the calculation with your own numbers).

See Pythagorean theorem - Wikipedia, the free encyclopedia for an explanation of the formula used.

Thanks Offset Guy.

Al

Al,

Nice use of math. ( I saw the attachment but then it was gone. ???)

Actually rubber rollers would deform a bit and produce a bulge on either side of the stripe which tends to increase the stripe width. This would mean that the stripe width would be reached even before the squeeze value you calculated.

Rubber is a special material. When deformed, it does not lose its volume. Not many material behave this way. So when pushing the rubber in at a nip, some rubber material has to be pushed out some where else. If you deform steed, it actually loses volume.

But even with the simple model you used, you got a relatively good idea of the physics of the problem.

That is great to see. People don't realize that even when making some simple calculations that are reasonable, one can get a new understanding of a problem. Like the simple calculation for density control. Ink In must equal Ink Out.

Erik

 

[Al Ferrari]

Erik,

Thanks for the supporting comment and your additional explanation. Yes, I just wanted to show that even with my simple model we could see that we should expect the reported difference in the washup with and without the plate.

Al

 

[GazKL440]

I never thought that pythagorean theorem could , or would be applied to printing!! learn something new every day Its funny how in every day use of a machine you rarely consider the engineering and mechanical and mathematical knowledge that has been bought together to reproduce a good print. All these things hide behind ergonomic design and wonderful technology... and if your ever lookin at the insides of it you have some sort of major problem...

I never wash up a press without a plate on so didnt even consider that it could have been the problem.. and never would have looked at mathematical theorem to sort it.. a quick check of stripes on the plate showing the minimum 3mm required for transfer ink... and you know if have a problem or not.... run on

 

[Bacon3302]

I would rather wash up with a plate installed. Unfortunately I am stuck using 10”(25.4cm) and 12”(30.5cm) wide plates so the ends of the rollers wouldn’t clean up. This forces me to run a form roller stripe between 0.16”(4mm) and 0.17”(4.3mm) wide so that there is enough contact with the bare plate cylinder to facilitate wash-up. So far this hasn't caused me any problems.

I do like the Crestline system but another issue I have with them is the metering roller is 1/8”(3.175mm) wider than the pan roller, or visa /versa, I forget which. This causes ink to build up on the very end of the longer roller to a point where it begins to fly off.

Is it just me or am I stuck with this problem

 

[Al Ferrari]

The pan roller is the widest, and the metering is wider than the form. This is so the form wets all the way out to the ends. Very little ink should be making it's way back to the pan. I usually touch a water + solvent soaked rag to the pan roller ends during the wash up.

On using undersize plates, it occurs to me that long term this could cause scoring of the forms that would show up when that wide image is printed down the road. Is this going on just to use up some plates that came with the press, or is it a cost saving policy set in stone? If the potential scoring does occur, the cost of replacing 6 ink and two water forms may not justify the savings in the use of the narrower plate size. But perhaps you are in a nitch market and that wider image will not be coming to this press,

Al