Laser Plates - HP Laserjet 5000/5100

[jpfulton248]

I just got a sample pack of Genie laser plates for testing with our Laserjet 5100 and our Itek 975pfa. I have my print settings pretty well worked out. Printing from Acrobat Pro at 1200 dpi and 106lpi with media setting on Cardstock. Not brand new, but OEM toner being used. 2 problems I'm having:

1. More often than not when I produce a plate, there are a couple places on the plate where I see streaks. Usually it's in a location where there is a solid or a dark gray scale... there is a one inch long streak starting inside the solid and dragging outside of it. Almost like a roller is dragging the toner out of the solid before it has time to fuse. Regardless of what the details of the cause are, there are definitely streaks on some of the plates in a couple spots... steaks are about an inch long and again -- only after solids.

2. Our pressman hung one of the plates and tried running it. As far as I know he didn't do any prep to the plate and hung it right on the press. He used the existing fountain solution that he uses with our standard plates. The images coming off the press were very dark and all of them had a strange "outer glow" or drop shadow effect...

We are done testing for now until we have another offset job coming through but in the meantime -- anybody have any ideas?

Thanks in advance

Pete

 

[jpfulton248]

Update: I rummaged through the trash where i threw away failed attempts at imaging plates and found one where there was obvious toner scatter surrounding the darker text and graphics areas. Almost a halo effect. I am very sure that is exactly what happened with the plate that the pressman tried running which is what caused the poor print quality. Mystery solved. I imaged another plate and he's running it today. I'll update this thread again once he runs it.

 

[jpfulton248]

Update 2: I think the plates we had were bad. We got a new sample pack and we are no longer having any problems... almost no problems...

We don't own a plate punch so our pressman hasn't been hanging the plates on the pin bar (he's been using the other clamp that pierces the plate as you are hanging it). Well, after about 400 impressions the holes are beginning to tear and the plates are slipping. Apparently one actually flew off after stopping then restarting the press. So our next plan of action is to find and buy a used punch and also some of the laser plate reinforcement strips I've seen for sale.

P.S. Anybody have a used 25 hole pinbar punch they would like to sell or know where I can get a cheap one? We are running 12 x 18 plates. Thanks!

 

[jpfulton248]

Update 3: We had good luck last week running the plates last week though did experience very bad plate stretch after only 200 impressions. We got a sample of metal reinforcement strips and we've had good luck with those as far as plate stretch but we are now suddenly having problems with quality again (obviously unrelated to the reinforcement strips). The problem appears to be an issue with not enough pressure between blanket and plate cylinder, however checking the "stripe" appears that the pressure is right on or even too much pressure.

We tried using a chemical called blanket fix which swells the blanket and therefore increases the pressure from blanket to plate... this perfected the image quality. Absolutely what we are expecting to see from these plates.

No solution yet but we keep trying different things... just wanted to give another update.

 

[kyprinter]

Laser Plate help

Laser Plate help

This is dated information but still has a lot of useful info…hope it helps.

 

[jpfulton248]

Great info. The computer side of things is a little outdated but of course the concepts are still the same. This is the most details I've seen regarding the press side of things. Thanks for posting. We've been working with someone at stuff4print.com and he has been tremendously helpful up to this point. As it stands we are continuing to trouble shoot.

By the way, has anyone out there gotten laser plates running on an Itek 975pfa / Ryobi 3200?

 

[pdan]

Pinbar's and plate stretch go hand in hand and always have. Those reinforcement strips sound (costly and) time consuming. (I think a plate should be able to hang in 30 seconds or less

The normal solution is to spray the back of the plate with "Spray Mount". They are typically termed "Repositionable Adhesive"

3M was the product for years. (Formula 5065 (?) standard tack and Super 77. The Super 77 variety can almost hold bricks to the wall, (I avoid it.) Currently I have Scotch brand.
Get some standard Spray mount; I would think any paper merchant would have it.

Spray the back of the plate, mount it. If necessary, also spray the chrome plate cylinder. Read the can.
Bonus usage - If you are sending out product in the plain letterhead boxes, spray and attached a sheet to the top of the box for a more professional look than packing tape.

Always etch a plate if you are not certain that everything about a press run is up to par. We tend to get lazy...poor washups, not etching plates, old developer, off the shelf inks of various brands, old rollers improperly set...one day (or many) your going to have sub-par printing and you'll chase your tail wondering what you have neglected. In practice a duplicator will put out "acceptable work" with everything at 80% good. Let some variables fall below that and you'll kill hours, days, developer and money trying to find out why.
fwiw, I haven't used a metal plate for years and I ran cmyk process on a regular basis (before digital and wholesalers). My plates often fall into position on the first hang; I try hit color and position in 0-3 sheets.

 

[OkiTech]

Hi, I've run laser plates on:
AB Dick 360 CD
Multi 1250W
AB Dick Century 3500S
RYOBI 3200 PFA
TOKO R2 SH
and now on AB DICK 9810
Xante's own plates work the best, others - OK but supersmooth surface tends to pick up background and cause picture framing.
As previous posted stated - forget about strips - repositionable glue sprayed on the back of the plate works the best - downside - should you need to make adjustments to the plate position, you'd need to peel it off completely.
Printer must be a perfection, NEW OEM Fuser, Laser optics must be clean, transfer rollers new, Cartridge best OEM.
If you experience plate stretch - check your pressures, all rollers + plate to blanket. If specs say 3-5 mm strip - make it 3-3.5, you can't pound poly plates with pressure as you can metal ones....
Good luck.

 

[jpfulton248]

Hi, I've run laser plates on:
AB Dick 360 CD
Multi 1250W
AB Dick Century 3500S
RYOBI 3200 PFA
TOKO R2 SH
and now on AB DICK 9810
Xante's own plates work the best, others - OK but supersmooth surface tends to pick up background and cause picture framing.
As previous posted stated - forget about strips - repositionable glue sprayed on the back of the plate works the best - downside - should you need to make adjustments to the plate position, you'd need to peel it off completely.
Printer must be a perfection, NEW OEM Fuser, Laser optics must be clean, transfer rollers new, Cartridge best OEM.
If you experience plate stretch - check your pressures, all rollers + plate to blanket. If specs say 3-5 mm strip - make it 3-3.5, you can't pound poly plates with pressure as you can metal ones....
Good luck.

Regarding the adhesive: I like the idea but I think our pressman is concerned about it gumming up the press. Will that actually happen? Any special steps that need to be taken to clean it off? Also, how often would it need to be cleaned? Between runs?

Regarding pressures: We seem to be having the opposite problem. Our print quality is showing evidence of low pressure from blanket to plate even though our pressure according to the stripe, is in the 5 range. Also, for some reason our pressman can't figure out how to lessen the pressure. He seems to think that the current setting is maxed out at 5 (like can't adjust to get a stripe smaller than 5). I'm wondering if making an adjustment from ink roller to plate pressure would affect the pressure from blanket to plate. UnlimitedBT - since you have run a 3200PFA, any tips on any of this? Thanks in advance.

 

[pdan]

Re: adhesive for the plates. In practice you would hold the plate at 1/2 arms length and spray the back of the plate lightly. This suffices most situations. You can mount the plate, perform normal setup actions, remove the plate several times and the adhesive will maintain its integrity. If the results are not sufficient, lightly spray the plate cylinder also. The operator is concerned about over-spray and gumming up the machine - fair enough. I, and countless others, have spray mounted plates for 30 years. At the end of the day perform basic clean up to the machine. The adhesive cleans up well with roller/blanket wash. (For chrome plate cylinders some operators prefer to clean with etch. Etch maintains/assists the cylinders water affinity.)

Stripes & pressures - are the laser plates the same gauge as your other plates? 5mil, 6mil or 8mil?
Lessening the pressure of Rollers to Plate will not effect the Plate to Blanket. Be mindful the heavy roller pressure will also cause "plate stretch". 3 mm is plenty, 5 mm is max.

Plate to blanket. Start up the press, idle. Does the 975 pfa have a (next) position to plate in contact with the blanket? normally between ink rollers down and running position. Let the plate contact the blanket for 1 or 2 impressions. Stop the press and visually check the image to the blanket. It should appear satisfactory.

I have never seen a 975 pfa, but to my understanding they are a blanket to blanket impression best suited for type & line copy and not the best for solids. Is this the situation? How old are the blankets? Glazed? In practice, depending on your needs these machines may be better served with a less compressible blanket.

 

[jpfulton248]

I'll convey the adhesive info to the press op. Thank you. My opinion of that subject is exactly what you stated... people have been doing it for years. It's fine.

I know almost nothing about our press (or any for that matter). I know a little bit of info based on troubleshooting with these plates and a few other press issues we've had over the last few years. I do know that our normal plates are 7mil, these are 5mil. I can absolutely verify that this press is blanket to blanket and is not designed for high quality work. My opinion however, is that we should be able to get a solid to look fairly consistent. Also, our 25% screens our splotchy. I've seen the press do much better with our other non-laser plates. I think the real trick is figuring out how to adjust the pressure. Something isn't right obviously since we are having extreme stretch issues, our pressure is probably already too high, but when simulating an increased pressure by using the blanket swelling chemical, we get the print quality we are expecting. Oh, and the blankets are less than a year old according to the press op.

I'll pass some of this onto him and see if it helps. One of the obstacles I am having here is that he is not very motivated to get the plates working. I can't do anything without going through him and he seems to be kind of bummed out that he has to do something new (even though these plates will only be used for jobs that we want better quality on). He has complained about punching taking too long, hanging the plates being too hard, removing the backing on the reinforcement strips being too hard, the tail flapping on the plate, plate stretch and the adhesive potentially being hard to clean. Think someone might be set in his ways?

 

[pdan]

not very motivated to get the plates working

Human behavior.

He has complained about punching taking too long

That's bunk, unless there's something odd in your workplace...it's a 3 second movement. If your punch does not have a guide, place a piece of tape in place for consistency.

hanging the plates being too hard

It is not as easy as a metal plate. It will become simple and quick after 30-100 plates

tail flapping on the plate

No different than any other plate, clamp it (or double spray the tail) - Is the plate long enough to use the tail clamp? My memory of a 975 is a pinbar lead, with the option to use a straight clamp for unpunched plates and a piercing tail clamp. Piercing tail clamps caused bleeding fingers once or twice, I punch lead and tail and use the lead pinbar and tail clamp.

Curious, are you using metal plates for everything up to this point? or a daylight camera?
Metal plates for simple work are, imo, time and cost prohibitive - most manufactures have left the market, costs have skyrocketed and unless you're extremely adept metal plates don't fall into place with much consistency from job to job. Heck, a 20 page book would involve 60-120 minutes in prep.

No tech would want to troubleshoot with year old blankets...I've gone that long, but with less than stellar results,
Blanket swell formula's always help.

Technical notes. (I run 5 mil poly.) You are altering the diameter of the plate cylinder with respect to the 5mil, 7mil. It is not much, but, diameter dictates the circumference of the plate cylinder. For a 1:1 measure the blanket cylinder and plate cylinder must be the same. I have found that the 2 mil difference will amount to running long slightly under 1/16 inch. (I can expand on the idea; it need not be an issue for down and dirty work, but you cannot mix plate gauges and run the same length for a two color job)

If you want to pound a screw with a hammer, and I've been known to do this, to check or increase plate to blanket - pack under the plate
Spray mount the thinnest sheet you have to the plate cylinder before mounting the plate, or hang the plate at the head clamp, than tuck a sheet under it, roll the cylinder and mounting both. Thinnest sheet - do you have a caliper gauge or micrometer? 20lb bond or better (thinner?) the slip sheets used between packaged metal plates.

The end result of all these endeavors will pay off - plates directly imaged on a decent device will fall within 1/32 of an inch every time - Your press operator will works less. Stick with it

 

[jpfulton248]

That's bunk, unless there's something odd in your workplace...it's a 3 second movement.

I've probably punched as many plates as he has in the last couple weeks. It's amazingly easy and fast. We purchased a nice (used) punch.

It is not as easy as a metal plate.

I watched him hang one. It does kind of look like a pain in the ass but there are a lot of people doing it in the world.

Curious, are you using metal plates for everything up to this point? or a daylight camera?

Daylight camera with ABDick "MEGA Plates". The extra time spent hanging and punch laser plates for him is offset by him not having to operate the camera. I also offered to punch the plates for him before bringing them to him.

increase plate to blanket - pack under the plate
Spray mount the thinnest sheet you have to the plate cylinder before mounting the plate, or hang the plate at the head clamp, than tuck a sheet under it, roll the cylinder and mounting both. Thinnest sheet - do you have a caliper gauge or micrometer? 20lb bond or better (thinner?) the slip sheets used between packaged metal plates.

When you say "sheet" you mean sheet of paper, right? My boss (also knows almost nothing about printing) suggested that, but the press op convinced him that the paper would disintegrate from all the water... we are talking runs of less than 3,000 by the way. We do have a micrometer. So try to find a sheet that is about 2 mils, spray mount it to the plate cylinder using the clamp then hang the plate over that and then run the job? Won't the paper disintegrate from the water?

Thanks for all the advice!!

 

[pdan]

Yes, you might pack under the blanket as a test to whether more plate to blanket is advantageous. To much pack and the plate will image the blanket before setting the machine (control handle) for plate to blanket. (This will also increase the roller stripes to plate, a bit...)

Some things are trial and error. I'm pondering where the differences may be between the daylight camera plates and the laser printer plates. The commonalities - straight cut, requiring punching - should be etched before mounting - I don't see the hurdle here...
The differences - Camera plates do not reproduce screens very well, which is likely one reason for adopting the laser plate. Camera's don't have great plate to plate image alignment consistency, and also require fresh chemistry, periodic maintenance and cleaning of the chemistry racks. If your press op is cleaning and maintaining this, he would be happy to give it up. I literally cut the cord to my camera (had to install a 30amp service for a new machine one day). I love being done with camera plates.

The laser and camera plates - are they poly (shiny, dark back surface) or paper, white back? Doesn't matter, both tear at the punch holes. I've experienced plates flying off during a run, most operators have.

Not much water will transfer through the plate surface to any packing underneath; it would not be cause enough for concern.

I could have mentioned earlier - spray mount is pretty popular in crafting, you may not need to order it and wait for delivery. Your local craft shop, sewing shop (do people still sew?), art supply may have it available. Auto part stores have the super aggressive tack -

 

[jpfulton248]

Yes, you might pack under the blanket as a test to whether more plate to blanket is advantageous. To much pack and the plate will image the blanket before setting the machine (control handle) for plate to blanket. (This will also increase the roller stripes to plate, a bit...)

The pressman has told me that the long time tech we use once told him that this press automatically adjusts blanket-to-blanket pressure. Messing with that setting can seriously harm the press. I would assume that, if true, packing the blanket(s) or packing the plates would also harm the press. Do you think it's possible that this is true.

The commonalities - straight cut, requiring punching - should be etched before mounting - I don't see the hurdle here...

Actually, we don't punch our camera plates -- he uses the auto inserter.

If your press op is cleaning and maintaining this, he would be happy to give it up.

He does maintain, and quite well I think. He should be happy to give it up but he's just being a dick about it. I think half is that he doesn't want to believe that new technology can be easier/better and half that he doesn't want the new hassles... he likes the old hassles. Also, he tried the spray mount and HATES it. He said it's hard to clean up (even though I told him not to clean between runs which he did anyway and I personally am aware that it took him about 10 minutes to clean up).
[/QUOTE]

The laser and camera plates - are they poly (shiny, dark back surface) or paper, white back? Doesn't matter, both tear at the punch holes. I've experienced plates flying off during a run, most operators have.

I'm pretty sure we are using ABDick Mega Plates which are purple on one side and white on the other. Not sure the material. Paper rings a bell but so does polyester. I know they are 7Mil.

(do people still sew?)

My mother still sews.


Questions:

1. I believe that our plate to blanket stripe is 7 (i assume this is mm?). It's supposed to be 5. This doesn't concern the press man even though I believe it should. My theory is that we are wearing out the blankets faster than we should be and therefore our grayscale quality starts sucking after a few months. Our current blankets are about 4 months old. Is it possible that replacing them would improve our quality already?

2. Is it possible that packing the blankets or packing the plates could harm the press?

3. Anybody with experience running these plates on the Ryobi 3200pfa / Itek 975pfa want to travel to Michigan to teach our pressman how to run these plates on our press? That's actually not a joke -- my boss offered to pay for someone's travel and expertise.

 

[pdan]

hmm, i'm in Livonia.
Have you made a decent transition to the Laser plates?
How many plates might you run in a week; Camera vs Laser?

(I'll try to stay focused on) an original question, that plates are stretching. If you camera plates are striping to the blanket at 7mm than the laser plates are going to be striping close to the suggested 5mm. You can always go less plate to blanket. I would suggest the softest kiss possible between the two. On a Ryobi 3302 it's a simple on the fly adjustment. Back away the pressure until you see the image sacrifice or a low spot on the blanket. Increase slightly. This minimizes plate stretch - it is the plate to blanket friction causing stretch. (Actually, it's pinbar hole elongation) I'm don't expect it is as simple with the 975pfa.

A 3 month blanket cycle for a machine in daily operation would not be considered excessive. It is where the ink meets paper. Think ROI. I'd ballpark that at over 300 jobs...$120 in cost / 300 = $.40 per job. (Pressman love new blankets...and rollers...)

Grayscale quality degrades - poor reproduction of dots. Camera chemistry or blankets.

 

[jpfulton248]

pdan-
We are in Madison Heights. I75 and 12 Mile. I know I've asked if you've ever run the laser plates on our press and you said no but have you ever run our press at all? Have you run other perfector presses? If the answer is yes I seriously think my boss might try to convince you to spend a few hours with us as a paid consultant.

We have not tranisitioned to laser at all. All camera still. Actually the pressman said he wouldn't be happy until all of the laser plates were in the trash. As far as how many plates we are using i'd have to pull some numbers... we do a decent number of jobs on a digital printer as well. I'll give more info later. Thanks!