Changing Blankets on Itek 975 PFA / Ryobi 3200 PFA

[jpfulton248]

My press operator has been running this one single press for 20 years. Until about 3 years ago he never packed the blankets because he didn't know that he was supposed to. He says he has never had any problems putting the blankets on until 3 times ago (we change them every 9 months or so). He doesn't struggle on the bottom unit but I just helped him put the top on and it was an ugly scene. We used an allen wrench to pry the blanket on. I torqued the wrench while he pushed the blanket into place to get it to snap in. First we tried it with 24# packing. Couldn't get it on. Then we tried 20# packing. Couldn't get that on either. Finally we tried with no packing. It took us about 40 minutes of prying and pushing before we finally got it to snap into place.

What are we doing wrong? Is this totally normal. It sure as hell doesn't seem normal.

 

[Alois Senefelder]

Hello jpfulton,

Unbelievable !!! You are using the correct size of Blanket for a start ?????????????



Regards, Alois

 

[jpfulton248]

Press operator had me purchase them This is what he had me get:

43189-P

ITEK COMPRESSIBLE 12.2" X 19.2" .075" ITEK GRAPHIX PRESS BLANKETS 975 PFA

 

[keith1]

You are packing the blanket waaaay too thick. All that should be needed is the thickness of tissue paper. Also; every 9 months or so is a long time. You change the blanket when it requires changing. Sounds like a good time to get someone in to check and correct pressures and start over again.
As a general rule of thumb, after mounting a new blanket - without packing - run it in for several thousand impressions, then put a sheet of tissue paper behind it. I used to use the thin paper that separated metal plates in the box of plates.
The press manual should give you the correct thicknesses. Of course you'll have to go through and correct the roller pressures as well as the cylinders.

 

[jpfulton248]

That's what I thought. I try to be careful how much I say since I am a lot younger than him, have no professional training and have never run a press. Keep in mind we ended up going with no packing and still had an incredibly difficult time with it.

As far as length of time. We barely run any offset anymore. We have moved a ton of stuff to digital. Also he is lazy. We have tried to get him to change them every 6 months. He prefers to wait until he sees a problem with print quality which I understand but I'd prefer to change them out ahead of that. The only reason he changed them this time is because I told him to and we have a big job coming right around the corner.

He did not check pressure and probably isn't planning on doing that. Like I said, I have to be careful how much I tell him what to do. He'll begrudgingly do it because I am essentially his boss but first he'll tell me I don't know what I'm talking about and be a dick for a while.

Yes, we have a bit of a personnel issue.

 

[jpfulton248]

A 3200 is a Ryobi duplicator (no bearers) model, correct? If so, you aren't supposed to pack these blankets, it's a duplicator so no packing is needed. The blankets should come to you in the correct thickness already and to be sure they're what you need, get yourself a micrometer and check it with the machine specifications for cylinder undercut.

I could be wrong of course but you also mentioned that he ran this machine just fine for years without packing, what changed everyone's mind about that?

"fine" is subjective. His quality kind of sucked. One day the repair guy was in here and I think the subject of packing came up. I believe the repair guy is why he started packing in the first place. What you're saying would definitely explain why he hadn't done it for years.

The other issue still remains... why is it such a struggle to put the blanket on the top unit even with no packing.

 

[keith1]

Forgot to mention in my earlier post. I ran the 2 colour Ryobi that had separate blankets. It's been quite a few years since. Neither here nor there. I recall having the same problem mounting a new blanket. I would mount one end but keep the screws as loose as possible to allow as much slack as possible to get the screws on the other end to grab. Yes, it was a pain. I used a screwdriver much the same way you use your allen wrench to torque the blanket into place. Once you pried the blanket bar around the cylinder the fit was good though and you could tell that it the blanket had been longer, to permit it to wrap around the cylinder better, it would have been too long to tighten properly. Just something you have to put up with and after a few blanket changes you develop a system (of sorts).
After installing a new blanket and running a few jobs, it's important to retighten the blanket if needed because it will stretch out a bit.

In theory, a compressible blanket shouldn't need packing. Not like a non compressible on a bearer press where correct packing is critical. However a new blanket will flatten out just a little bit and that's where your thin tissue like packing enters the scene.

If you aren't running the press daily, maybe every 9 months does work for you. But really it's when solids & halftones start looking kind of not so good. I've seen new blankets smashed within an hour.

 

[jpfulton248]

If you aren't running the press daily, maybe every 9 months does work for you. But really it's when solids & halftones start looking kind of not so good. I've seen new blankets smashed within an hour.

Funny, I was actually going to ask you what your experience running solids was. Also, the whole reason I asked the press operator to change the blankets a couple days ago is because we have a job coming in the next week that has big solids on every single page. Total job is 30 plates and about 2,500 sheets per run.

EDIT: To give you an idea of our usage. This is the largest job we do all year. We probably run the press twice a week on average.

 

[Alois Senefelder]

Hello keith1


You are wrong! ............ ALL Compressible Blankets NEED to be overpacked on whatever press they are fitted.


Regards, Alois

 

[jpfulton248]

Hello keith1


You are wrong! ............ ALL Compressible Blankets NEED to be overpacked on whatever press they are fitted.


Regards, Alois

Well, I certainly am not qualified to comment on this but I can say that this label is on the box that the blankets come in. Picture below. (note line 3rd from bottom).

 

[Alois Senefelder]

Hello jpfulton,

You must remember that Ryobi buy in Blankets from well known Japanese manufacturers, also Blankets are manufactured to +/- tolerance

I also used the word "overpack" not under-packing.


Regards, Alois

 

[dabob]

Hello jpfulton,

You must remember that Ryobi buy in Blankets from well known Japanese manufacturers, also Blankets are manufactured to +/- tolerance

I also used the word "overpack" not under-packing.


Regards, Alois

So Alois, we should put the packing over the blanket?????

 

[pdan]

I'm going to disagree with the idea of packing. I have 20 years with the 975 but not the pfa model. (I have peers who have had this machine forever.) pfa is perfector correct? Blanket to blanket for impression, no true impression cylinder.
Because of the blanket to blanket impression they, to what I have heard, are not as able to produce strong solids or excellent halftone dots. If you have another press in the shop you can confirm this or inform me I am incorrect.
Packing always seems to help - I am in a frequent "Let's do it", "Let's not" with my current employer. (I favor the latter). I find that packing frequently slips and all that extra banging of cylinders cannot be good for the whole machine in general; the parts taking the abuse would be the most crucial for consistent impression. For example, I have been in this current shop for 18 months after 20 years as a small shop owner. Two 3200's cannot run at over mid speed - they will jump out of impression or fail to go into impression.

 

[Alois Senefelder]

Hello fellow "Lithographers" should there be any left in America ??????????

1) Hello dabob, ----------- You would not win the Comedian of the Year Award in Americas Got Talent Show ! .... I know this would be a great disappointment, but you have to face reality.

Hello pdan, I suggest you refresh your knowledge of " The Mechanics of Lithographic Printing" !

I await the "Hue and Cry"


Regards, Alois

 

[dabob]

Alois . . . hard to be funny about packing . . . leave out snarky remark . . . but I ran duplicators which the 3200 essentially is for over 40 years alongside of some bigger iron, Harris, Mehile, and now Heidelberg I have never ever packed a duplicator blanket . . . there is imho no reason to since those cylinders dont have a bearer just a little eccentric that controls the blanket to impression cylinder and another one that controls the plate to blanket . . . these little goodies effectively take the place of having to pack either the blanket or the plate . . .


Just to humor your remark, about refreshing my "knowledge" knowledge of " The Mechanics of Lithographic Printing" I got out my copy of The Lithographers Manual, that was published in 1966 by the GATF. Delved deep into the knowledge enclosed and could not find one mention of using packing, either plate or blanket on any press that was constructed without bearers and having to deal with printing short or printing long and how that could be corrected by differing the plate and blanket packing to compensate . . . but nary a word on bearerless presses . . duplicators have little or no need to compensate for printing length difference since, 1. its usualy 1 color work, 2 the distance around a cylinder is much less than a large press, and 3 registration between colors is usually not that critical . . . .

just my 2 cents.

 

[Alois Senefelder]

Hello dabob,

Like all good stories, I'll start at the beginning.

Re- my post about Compressible Blankets, you chose to answer with a "Stupid Remark" !

Your need to enter scenario of what presses you have experience of, I can match you "Like for Like"

Onto the crux of this discussion, the same fundamentals apply to Bearer Contact/Bearer Clearance Cylinders- these are:

1) Gearwheels 2) Pitch Circle and the area of radial adjustment regarding blanket heights and the means of achieving this

fundamental task.


Regards, Alois

 

[dabob]

Hello dabob,

Like all good stories, I'll start at the beginning.

Re- my post about Compressible Blankets, you chose to answer with a "Stupid Remark" !

Your need to enter scenario of what presses you have experience of, I can match you "Like for Like"

Onto the crux of this discussion, the same fundamentals apply to Bearer Contact/Bearer Clearance Cylinders- these are:

1) Gearwheels 2) Pitch Circle and the area of radial adjustment regarding blanket heights and the means of achieving this

fundamental task.


Regards, Alois

Alois . . .

1st my "stupid" remark was in relation to the ryobi blanket label was "humorous"

2nd what presses have I operated . .. . hmmmmmm lets start with

multis (from 8.5 x11, to 11x17, to 14x20 models, Chiefs 15, 17, and a ATF chief 22*, hamadas 8.5 x 11, 12x18, 14x20, AB Dick from 8.5 x 11, 11x17, 17x22, and an AB Dick perfector (needed 2 press units and a turnover conveyor in the middle -haven't seen one either before or since) Robi 11x17, Harris 26 inch*, Miehle letterpress/die cutter*, Kludge 10x15, 12x18 (printing, foiling, die cutting, and embossing), Heidelberg red ball windmill*, Heidelberg* GTO ZP 46, Zp 52, 52, SMORZ, Speedmaster 2/c 72 and 4/c 72 both with perfectors, Cylinder 30" die cutter* , Chandler & Price platen press*. These are the ones that I can remember off the top of my head.
(* indicates packing is required)

Also had 5 years of "schoolin" in a classroom environment, 2 years as a teachers assistant (while I got my electronics degree) and going on 50 years in the industry.

So I guess we will just do it our way on this side of the pond and you can do it your way on your side . . . .

-30-

 

[Alois Senefelder]

Hello dabob,

1) OK ........ I read your reply "wrong"

2) I'm not naming various manufacturers of printing presses - -

3) I served a Six year apprenticeship, attended a UK School of Printing Technology.

4) During my Fifty + year printing career, I was Pressroom Operations Manager at a leading UK National Newspaper also at a UK Web Offset Printers.


This reply ends my discussion regarding this part of the "Topic"

Regards, Alois

 

[dabob]

Hello dabob,

1) OK ........ I read your reply "wrong"

2) I'm not naming various manufacturers of printing presses - -

3) I served a Six year apprenticeship, attended a UK School of Printing Technology.

4) During my Fifty + year printing career, I was Pressroom Operations Manager at a leading UK National Newspaper also at a UK Web Offset Printers.


This reply ends my discussion regarding this part of the "Topic"

Regards, Alois

Just gotta throw this out there . . . seems like you have lotsa experience in Newspapers and web offset . . won't argue anything about web presses . . . but this discussion was specifically about duplicator type presses of which you have very little experience of apparently I may have as much experience about web presses basically zero . . . but it has been my experience that it is better to keep your mouth closed when you don't know what you are talking about . . . you will not find me commenting on any web press question on this forum because I have almost no experience with them - other than going with my father when he went to his job as Production Manager at the Detroit News, Houston Chronicle, and San Francisco Newspaper Printing Company . . . so i've seen some really big webs but would never claim to know anything about them other than they are impressive especially when you are 5 years old standing next to a GOSS web press thats 3 stories tall and a block long.

But apparently you didn't note that "-30-" is what a reporter writes when its the end of his story at a newspaper . . . . so once again

-30-

 

[Alois Senefelder]

Hello dabob,


I despair ! .......... WHY is printing by Lithography any different on a Duplicator or a VLF Press or even Web-Offset other than size ???????????


YES I did spend my first years in Sheet- fed So I do KNOW something about them !!!!!!!!!!


Regards ......... yet again Alois