Bizarre!

eyetech

Active member
OK this is a new one to me...

2 sets of plates imaged last night. (AGFA Palladio 30)

In each case two plate out of each set imaged in a different grip position.
ie position from grip C = 64 M=70 Y=70 K=67 (mm): second set c=70 m=67 y=67 k=68

The render shows the all seps at the correct distance of 63mm

So anyone any idea what is going on? Subsequent plates are ok.
 

Lukas Engqvist

Well-known member
Could be you need to have a plate edge detection sensor cleaned. Could also be your punch needs cleaning or your clamps that hold the plate in position need adjusting.
 

eyetech

Active member
I'm guessing all those are engineers duties or is it simple enough to do oneself? Not even sure where the plate edge sensor lives.

We've run over 200 plates since the 'event' and had no similar result.
 

VladCanada

Well-known member
Agfa Palladio 30 does not have neither edge detector nor clamps because it's neither "internal drum" nor "external drum" concept... simply "capstan" machine.
The problem caused by "plate pusher" system, which positioned the plate over the vacuum table.
Check white plactic edges on the pusher, may be they are worn out (thin lines on the edges which plates cut deeper and deeper).
Reinstall plastic edges to opposit surface.
 

Al Ferrari

Well-known member
"Agfa Palladio 30 does not have neither edge detector nor clamps because it's neither "internal drum" nor "external drum" concept... simply "capstan" machine."

Wow! what was Agfa thinking when they built this? I am surprised that there are equipment manufactures taking this approach. A capstan transport method was viable with film because it would be manually positioned on a light table. But plates need to be ready for press mounting without the need for plate cocking. Otherwise the only benefit gained is the absence of film. I suppose it's a poor man's approach to CTP.

Anyway, that's my take on it.

Al
 

maxon

Well-known member
Wow! what was Agfa thinking when they built this?

i'm surprised you're surprised. The Palladio (OEM) manufacturer is Screen, not Agfa. There are loads of flatbed platesetter machines everywhere Platerite, Palladio, Advantage, ECRM's Mako 2/4/8 in all flavors.
 

Al Ferrari

Well-known member
It would be better to keep the discussion focussed on the technology instead of the commentators. Fault me for not having done a survey, if you will. But are these other flatbed platesetter machines all capstan based?

The point of my comment was that the slippage factor inherent in that transport method makes it a poor choice for the application at hand. Especially considering that the drum design had proven so successful with filmsetting. As I said, this reduces the potential of this technological advance to eliminating film and film handling. I simply had not known that machines had been built and widely marketed with such a small improvement in the production of plates for press.

Al
 
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VladCanada

Well-known member
BTW any film setter, which images polyester media aka Mitsubishi SilverPlate or AGFA SetPrint - is a CTP :)
Leading screw moves the table with a plate sucked with vacuum - no any slippage produced in case of Palladio.
Saying "capstan" in case of CTP we mean flat position of the media and different length of laser beam's way in the center of the plate and on corners of the plate.
Flatbed ("capstan") systems faster than any drum concept machine - that's their advantage and reason to be at CTP market,
especially for newspapers.
 
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SteveAgfa

Well-known member
Al:

Different designs for different applications.

Often, flat-bed and/or capstan-drive CTP devices are found
in the newspaper market where hundreds of plates per hour
may be the requisite. The load/unload cycle for internal/
external drums can be counter-productive for such high throughput.

If I recall correctly, the Palladio is actually a flatbed, rather
than capstan.

Since you brought-up filmsetters, one could argue that the
capstan-drive Accuset killed the internal-drum SelectSet 5000,
as the price/performance of the Accuset ran circles around
the SelectSet 5000, dollar for dollar, or pound for pound.

So, not only different designs for different applications,
different designs for different market strata.

Regards,
 

Al Ferrari

Well-known member
Thanks for the info Steve. From your knowledge of the Palladio, can you venture a possible explanation for the positioning failures which began this thread?

Al
 

VladCanada

Well-known member
I gave you an answer, Al, but you ignored it.

I do not think SteveAgfa will give you an explanation because he is "one-of-whom-are-on-top", not actually AGFA Field Serviceman, as I was :)

OK, you ignore me - I'll ignore you.
Bye Al, you are very irritable today!
 
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Al Ferrari

Well-known member
Vlad,

If you look at the messages in threaded view, you will see that my 7:18 post was a direct response to your 6:01 post. That's not ignoring you at all. I am sorry you took offense just because I directed you to Steve's post. I was trying to point you to someone else's correct use of the term capstan.

My original entry into this discussion was brought on by your broad and misleading use of that term. Had your meaning been clearer, I would not have made my original expression of surprise that that method of transport was used in a metal plate setter. Your original message, emphasizes that the device has a poor transport system. Remember that the central subject of this thread is the controlled positioning of the plate for exposure.

Al
 

w3112

Active member
Sir,
An incorrect "grip" position is most likely caused by a mechanical problem. The plate pusher moves forward up to a specified position. But this position is not "measured". The pusher starts from a home sensor , and moves a number of steps ( stepper motor ) forward. If this movement is not smooth , you might have variations like this. I would start by applying some grease on the glider bars of the pusher unit.
If the variation is as big as stated ( 3 to 4 mm ) , I would not worry about the positioning blocks.
They can wear out , that is correct, but the variations would be much smaller.

And I have some more questions :
Can you specify how often this problem is happening ?
Can you send the details of your cassette setting ? Plate size , grip size , punching ?
Is the image skewed on the plates that have this variation ?


Regards,
W3112
 

SteveAgfa

Well-known member
Al:

This can all get very confusing, as there are grey areas at play.

Yes, there are CTP metal "capstan" devices, but perhaps more
accurate, some of these are drive rollers or nip rollers which feed
the plate across an imaging slit.

With your post to me about the original inquiry - I'm not tech support,
but W3112's response seems reasonable.

Regards,
 

Controlling the Purse Strings

Avanti
CONTROLLING THE
PURSE STRINGS

By Noel Ward, Editor@Large
What did you buy for your
business last week?
And how are you making sure everything you purchase is properly managed and accounted for?

Read the Article

   
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