movement during run

[Alois Senefelder]

Hi are you "Losing" any sheets during travel through the Press ??

[Albert Noel]

Originally Posted by Alois Senefelder

Hi are you "Losing" any sheets during travel through the Press ??

no, all sheets pass all the way through

[Sfdp2300]

Did you get a chance to get your speed up to see anymore doubling?

Im curious as to hear the outcome of this problem...


Even though Im still inclined to believe it is in your double transfer from the way the ghost image moves up and down...

[Albert Noel]

not yet, no.
haven't ran at a higher speed yet. been doing quite a few short runs that aren't normally ran at high speeds.
i should be able to by the end of the week though i think.

Originally Posted by Sfdp2300

Did you get a chance to get your speed up to see anymore doubling?

Im curious as to hear the outcome of this problem...


Even though Im still inclined to believe it is in your double transfer from the way the ghost image moves up and down...

[Alois Senefelder]

Hi Have you checked the "Backlash Gears " ???

[Albert Noel]

well, great. still having this issue with unit 2.

tried to run some 19x25 70# uncoated (483x634 104gsm) and ran into some nasty doubling again. same thing, only in unit 2. i could run at 12,000sph but any faster than that (even 100 over) and it would start to double really badly..
(actually, it was doubling at 12 but not bad enough to spoil the job)
i'm sure its the imperssion grippers on unit 2, but they wont bring a tech in to do them all for us. ugh. i would love to have the entire press done from a tech that knows what they are doing. (i'll openly admit i dont know how to adjust/set them all properly. the other op knows how but i dont think he spent enough time on them and he wont do it again, doesnt think theres anything wrong)

well, i'll report back when i figure it out

[akiyama_king]

try to put a small strip og the same sheet you are running in each of the grippers on that imp cylinder, if any of them feel loose you need to reset it (even if it is only according to that sheet) if they are all loose i would assume the machin has previously been used for thick board printing and so would need totally resetting because they are not closing to enough for a thinner stock

[Albert Noel]

Originally Posted by akiyama_king

try to put a small strip og the same sheet you are running in each of the grippers on that imp cylinder, if any of them feel loose you need to reset it (even if it is only according to that sheet) if they are all loose i would assume the machin has previously been used for thick board printing and so would need totally resetting because they are not closing to enough for a thinner stock

we're the original owners it was installed brand new in '99. no thick board, but i will recheck them again

[67drake]

Albert,in your post #6 you wrote that you get the doubling while printing the K alone. Is this with any other units on impression? This should help at least narrow down the problem.
For example,if you had a bad transfer gripper between the 2nd and 3rd unit,the black would double,but not until after it hit the 3rd unit blanket. If you are getting a doubling with just the second unit on impression,it would rule out alot of other variables. If it is doing it with just that unit on impression,the problem is isolated to that unit alone. I would think blanket or plate movement somehow.
This is a long shot,but do you have to move the K image down as you run to keep the black in register? You might want to make sure the bolts that hold your circumferential adjustment are tight. I have seen this cause the fit to move,not double,but I suppose in an extreme case it might double.
You also mentioned that you have the unit packed correctly. Did you use a packing gauge on it? I've seen blankets marked with the wrong thickness stamped on them,so I always use a gauge. I have also had the blanket/ packing swell up from wash up solution/water getting under them. This of coarse will throw out your squeeze.
Just throwing a few ideas out there.

[Albert Noel]

Originally Posted by 67drake

Albert,in your post #6 you wrote that you get the doubling while printing the K alone. Is this with any other units on impression? This should help at least narrow down the problem.

well, i finally figured it out and have to schedule a service call tomorrow when i get to work.
turns out one of the grippers on the perfecting cylinders straight printing gripper bar, had somehow come off of it's spring-loaded guide rod. it seemed pretty normal looking and even felt normal with a feeler guage however it must not provide enough tension as it doubles at speed.

originally it would double while printing black only, then i changed the way i ran the front guides and got it to go away while printing straight black/perfecting but couldn't eliminate it during process runs. today i was running only black on unit two and decided to turn on just impression on the next unit and sure enough, doubling like crazy at any speed faster than 12,000.
going to have a roland tech in asap. and get him to fix it and adjust the tensions on it and we should be fixed.

thanks again 67drake (and jbeniston too) you guys are awesome when i comes to trouble shooting. this problem was driving me nuts.

if either of you are ever in my neck of the woods, beers are on me