Ryobi 3302 Doubling

Have put on all new grippers. Trying to rid problem of doubling on second print unit. No luck, did find that rasie/lower device on second unit was locked up, greased and oiled up to free movement. This did not help. Is it possible that their is play in raise/ lower linkage?
This doubling only happens when running light coated sheets 70-80 lb with heavy solids, regluar offset no problem.

 

Loose blanket? You'll need to check and retighten the blanket a few times as they stretch. Turn the center tension dial with a allen wrench in one of the hole tills it's good and snug. Not real tight!.. but snug. Then tighter the 2 tail edge bolts 1/4 turn or enough to get it snug. Don't loosen the lead edge bolts, only the tail to change/tighten the blanket. Try not to overtighten the blankets too. What brand of blankets are you running? If there's still a problem it could be one of the cam followers on the impression cyl. Tell me something the unit you call #2 is it by the feeder end or delivery end? As some number then front to back and others back to front. If it's the unit by the feeder end it could be a static problem the Ryobi's are notorious for.

 

Also where did you put the new gripper fingers on? The transfer cyl or impression cyl?

 

Blankets are tighten correctly with tension device centered in middle threads. Blankets used are Syn-tac 5 ply punched. Unit 2 is the one by the deilvery. Grippers changed are transfer and impression X 2, with proper 1 degree of hang time between transfer drum and impression. Cam followers on the impression cyl have no wear. With stock under grippers can not pull sheet out of grippers.

 

Just so I understand "doubling" your saying the image is blurred correct? If so is it only vertical (grip to tail) or does it skew crooked? Are you positive it's not static? Have you tried a 100# sheet and would it do the same thing? Or another paper brand? And last what grain paper are you running on? If it's short grain you'll get that especially on a light coated sheet. And if you backoff on impression pressure does it still do the same thing? Except with a weak impression? If your printing a full size heavy solid on a lighweight coated sheet it's asking a lot of the paper on lightweight stocks. On some heavy coverage jobs I would have to double hit the back with both units. 60-70% screen on #1 and solid plate on #2 on some light sheets. It's hard to say exactly without being there thus all the questions. But being the press runs fine with non coated and I'd assume cover stocks I'd look closer at the paper. If it's a cheap #3-4 sheet try a #2. I've also had problems with some digital coated sheets too that are copier specific. Normally those are short grain box stocks 18x12 short vs 12x18 long etc..... Sorry I don't have a more direct answer.

 

Doubling, I hope is right term to use. What I see is when running sheets though second time is every second sheet is out of register by .5mm only on second unit. Using long grain paper. Will try using lighter impression pressure and dif. types of stock. Thanks for ideas.

 

Well that's a different animal. Registration issues can be a few different things. What ever the sheet size. Watch the side of the sheet isn't hitting the side springs and you have enough push on the jogger. I also run the skid wheels on the register board right off the rear edge of the sheet. And sometimes just kissing the edge depending on the paper and how fussy it is. Next be sure feedroll pressure is not excessive. By the book I think it's 1-1/4 revolutions of the upper steel feed roller gauging by the holes in it. But I go by feel and register checks and tighter on light stock looser on heavy stock till it's perfect. I'm sure you know the basics. Stock prep is key, neat even and straight. It could be either the lower rubber feed roller is beat, out of parallel or stop finger height isn't correct. If you replace it spend the money on the Ryobi brand feed roll. Trust me here. It could also be static as this is a major issue as I mentioned before. You can see the tail of the sheets side skew into the feedroller. Something that's a common flaw on most of the 2 gripper 3302's is the impression cyl. One edge has a high spot and can cause the sheet to sheet misregister like you decribe. If your running multiple color or process work it's a PIA. You can try hold back 1 sheet when you misregister and get it back on sync with the same imp gripper. Every one I've run has been the same except for a few that have been ok for some reason. A good bud of mine is a Ryobi tech among other brands and we've discussed it to length many times. I don't know if the casting design changed over the years but that and the static are 2 downfalls of the press. You can only do the best you can to work with it. Press speed can also be key. Slow and steady 5-7 iph is the good range. For a small offset press it's one of the best but it has it's drawbacks as some do. I have pulled my hair out as well trying to beat these things. Got to know it's limitations. I don't run 70# coated only 80# and up on the 3302. Paper has changed so much over the years most of the 80# sheets today mic what a good 70# sheet used to anyway. LOL. Again I'm sorry I don't have the pefect answer. Perhaps someone else has some insight on the subject. Your never to old to learn as they say!! Anyway best of luck and please let us know if you find a solution.

 

By out of register I mean up and down by .5mm every second sheet on second head. Trying to get back to sync by holding back sheet will be last resort. I did change lower feed lower as well with after market one. Also changed roller bearings of upper feed roller.
Thing I don't understand is how can register change up and down on second unit for sheet does not change grippers between units. Have seen many times that when timing is out between transfer and impression on either gripper bar of impression. Then you will see image bouncing up and down from first unit. Quess I will get out dial gauge and check impression cylinder. Thanks again

 

I don't know if you fixed your problem yet, One thing to check would be your impression cylinder fingers opening at the same time. you can check by putting a large screwdriver on the cam and opening each set over and over making sure the grippers come open all at the same time. If one or more grippers hesitate the slightist bit it will cause double imaging on every other sheet. To fix this problem under the cylinder guard there is a small allen screw to make adjustment. Be careful they are very touchy.

 

Hi THESAINT
Just read your thread, i'm not familiar with ryobi presses, are you running 4color work on a two colour press.
Inch a sheet through each of the gripper transfers and see if at any point you can pull the sheet out, if this happens you have a problem called "flying gripper transfer" where the sheet is momentarily not under control by the grippers,
let me know how it goes, regards johnyprint

 

Just worked on a Ryobi 4 color with the same problem. Some key things. If you are running 12x18 paper and it is running off to one side a little the outside grippers can and will cause a bad transfer. The edge of the sheet can hit them erratically and cause a buckle or even miss the outside gripper it is a very common problem and the best fix it to remove the outside grippers on the double impression cylinders. There are not too many running out their with them on cause of this. Another thing is if the sheet registers on the first unit and not on the second every other sheet as you said one set of your impression cylinder grippers is not set properly. Check for worn needle bearings on the gripper blocks and like already said check opening timing with the screwdiver under the cam follower. Unfortunetly on a ryobi there is absolutely no room for error with this adjustment. And if you do not have the proper guages to set them it is trial and error. Once you start setting them with that 2.5 mm allen screw you will notice they move way to easily. I have on several customers ryobis removed and used locktite to hold them in place. Just do not use the permenant stuff. Good luck

 

registration issues

I have been reading as many threads as possible relating to registration issues. FFR428 mentioned static as a possible problem. In another thread I read where an operator ran the paper through the press once without printing to help eliminate the static problem. We are running a 3302 trying to get side to side registration consistent. We have checked and double checked many of the suggestions I have found to no avail. When running the paper through the press is any water used? Also we have a static eliminator we sometimes use on our folder. If I mounted it on the press, would it be best to put it near the feeder or as close to the infeed rollers as possible.
Thanks for any help.