Couple of nagging Ryobi issues.

[lantz_xvx]

Hi everyone,

I've been able to keep getting my Ryobi 3302 with Crestlines dialed in pretty well - there's a bit of a learning curve with that dampening system. Nevertheless, I'm getting nice, sellable prints off it. But there are still a couple of nagging issues I just can't kick.

1) Color contamination. My lighter color is on the first head, usually black is on the second. After 600 or 700 impressions, stuff starts getting a little funky with the black creeping into the lighter color.

My plate is running clean but I still get bands of color on the sides, primarily on the first head, I believe. The black plate does get pick up some of the other color, though - I'll see it on the plate when I stop the press before I wipe it down again. Could that somehow be tracing black ink back into the ink train on the first head? On a perhaps related note, I'm getting bands of ink on the sides of the impression cylinder, mostly from the first head but a little from the second, too.

I haven't checked the form rollers since the weather started changing drastically, but I feel like I've always had these issues regardless of how the form rollers were set. It's possible I'm screwing up though.

2) The lead edge of my sheets are being nicked on the NOPS. I thought maybe it was the buckle, but if I loosen it too much, the sheet doesn't feed, and if I tighten it more, it never even makes it to the head stop to be grabbed. It drives me nuts, because it makes my stack look hella ugly and running the reverse side might be a huge pain. At its worst, I'm sure it can mess with my registration too. Any ideas on what could be causing this? I'm hoping it's an easy fix.

Thanks in advance,
- Lantz

 

[Al Ferrari]

Let's tackle the nicking firtst:

Do the nicks line up with the chain delivery grippers, or with the impression cylinder grippers?

If the nicks line up with the impression cylinder gripers, is it every sheet equally or every other sheet?

If the nicks line up with the chain delivery grippers is it every sheet equally or some other repeat pattern?

Or do the nicks line up with the stop fingers, and is it every sheet?

After you determine were the nicking is being caused, try to make a corrective adjustment to stop the nicking, or report back here with detailed information for further suggestions.

Now the color contamination:

The only way for ink to get from one unit to the other is via the impression cylinder surface areas not covered by the sheets.

My first thought is that the water setting is too low on the unit with the contaminating color. Try increasing the water setting on that unit and report back.

Al

 

[lantz_xvx]

Thanks, as always, for your thorough reply, Al. I hope I speak for most younger press operators when I say that we're grateful for the experience you and others like you pass on to us.

Now that I think back to it, the nick does seem to line up with the impression cylinder grippers. It seems to be nearly every sheet, though it can occasionally feed a handful or so of sheets that are fine.

It's the second one in from the NOPS that seems to be the problem. A fellow press operator looked at it and suggested that, while almost all of my grippers look great, that one was perhaps a little worn down. Do you think maybe I could take it off and replace it with the gripper on the end, closest to the NOPS? Would I have trouble feeding larger sheets without that end gripper?

Color contamination: you say that it is potentially the water setting on the unit with the contaminating color. In this case, I guess the color doing the contaminating is black on the second unit, but most of what's on the impression cylinder is the lighter color on the first unit. The water level seems to be fantastic on the second head, but I still had problems on the first unit. When I check the ratchet setting via the stripe, it looks like a good, even 4mm. Do you think that one or more of my form rollers are out of adjustment? If they were, I could see that not delivering enough water and having to adjust the Crestlines to compensate, causing the contamination problem. What do you think?

I won't be in the shop today, but will be there first thing tomorrow morning. I can check some stuff out then and report back.

Thanks again,
- Lantz

 

[pdan]

I shouldn't admit how many sheets I've printed with various grippers removed, both the infeed and impression cylinder, without noticeable issues. Eventually, multi pass cmyk on 12pt proved too problematic - verticle registration and nicking issues.
I would not advise replacing the impression cylinder fingers without knowledge of the procedure. Remove one with only slight hesitation.
(You will likely need an impact driver with a pillips head however. The screws don't remove easily and are easily damaged.) You can register as well without a couple as with worn out ones.
When new, there is a small amount of synthetic/rubber(?) applied to the end which contacts the sheet. Your's are very likey worn to bare metal. They should be replaced as a set, 16 (?) in all. There is a company in the states which makes replacements for half the cost of original eqiopment...think USD $20-$30 each.

Color travel - I'm thinking more along the lines of bad plate chemistry.

 

[Al Ferrari]

pdan,

That's very good input. Thanks for contributing, especially about the need for the impact driver. Do you recall any thing about the alternate source for the gripper replacements?

On the color travel issue, I was thinking that also, or an ink tack issue. He's getting excessive ink in water emulsion.

Al

 

[Al Ferrari]

Checking and maintaining your roller train in good adjustment is definitely recommended. As mentioned in pdan's 12:37 post,and my response to him, you are getting ink in water emulsification due to aggressive chemistry, low tac ink, or poor roller settings.

Al

 

[pdan]

Grippers, for more than just Ryobi, - GT Specialties in Albuquerque NM
It has been mentioned by a service tech, avoid the diamond coating; too aggresive against the cylinder.

About the impact driver, been bugging that I should edit post - Hand Held...Not pnmuenatic...can't spell it...busy..

 

[Al Ferrari]

Thanks for the gripper source while you're busy.

The correct spelling is pneumatic.

Regards,

Al

 

[lantz_xvx]

Hey all,

Thanks for the input thus far. I'm using poly plates and Universal Pink fountain solution at a ratio that works great on the second head. Runs clean, prints beautifully. I'm thinking more and more that one or more of the form rollers on the first unit is out of adjustment, causing an improper amount of water to be delivered to the plate. The plate won't run clean, and I have to raise the water just to get work done, which could certainly cause emulsification, correct? I'll check the settings tomorrow.

As far as the gripper fingers, I did check to make sure they were tight and I was able to loosen and tighten them with a very small phillips screwdriver, no impact driver needed. I definitely don't see any rubber on them, so you're probably right about them being worn down to the metal. But it's only that one gripper finger that is giving me any trouble. Does this mean that it's just more worn down than the others, and that the rest will eventually follow suit? What is the big deal in replacing them? From looking at them, it seems easy enough. Though, I can honestly say I'm not going to pay $30 x 16 to replace all of them. So the best option might be to just take that one off and move the one closest to the NOPS over one.

- Lantz