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Old June 19th, 2010, 09:32 PM
Doug Kerr Doug Kerr is offline
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Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,607
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I thought I might talk a little about a fascinating collateral aspect of serious newspaper printing.

Typically, at the production rates involved there, a roll of web stock paper can exhaust in as little as 10 minutes (the web may be traveling at up to 40 mi/hr).

Most serious press lines have provision for substituting new rolls on the fly with a system known as a flying paster. I was fortunate to find this nice video of a paster "firing" on YouTube:

http://www.youtube.com/watch?v=mAvUA...eature=related

As the scene opens, the roll that is finishing up is at about 3 o'clock (hard to see) on the three-arm carriage. The incoming roll is at about 11 o'clock. The next roll up is at 7 o'clock.

The blue stripes are double sided "web splicing tape", placed right at the free end of the web (which is now only lightly stuck to the layer underneath). The small rectangular tabs (sometimes they are black) are markers that allow the system to track the phase of the roll in preparation for the join. Today, it is required that both all this be "repulpable" so that they do not poison the plant waste, which is recycled into paper pulp.

When the outgoing roll gets near its ending diameter, the carriage is rotated to put the incoming roll into position for the transfer (about 12 o'clock), and the system begins to rotate the incoming roll, bringing its speed to where its surface velocity matches the velocity of the web. (You will be amazed to see how fast that looks - remember, the web is perhaps moving at 40 mi/hr.)

Then, when the outgoing roll reaches its critical end diameter, when the incoming roll is next at the proper phase, a roller hops in to slap the web onto the incoming roll, where it sticks because of the blue tape and pulls the free end from the roll. At the same time, a blade cuts through the web coming from the outgoing roll, which is now out of the picture, and the web is now being pulled from the incoming roll. (We can't clearly see either the roller or the blade, but we can see the dead tail from the outgoing roll flop down.)

The outgoing roll is quickly braked to a stop so the tail from it does not flop around.

Then the carriage is rotated to being the almost empty outgoing roll core to the 7 o'clock position so it can be removed and another new roll put in that spot.

The new roll is has already been prepped at an earlier station with the blue tape and black markers, so it will be ready to play its role when its time comes.

This rig is in the "basement" of the press room. There is one for each unit (or multi-color group). These presses almost always operate on a "double-wide basis", so for a press line with a maximum edition size of 48 pages, there would be six of them.

It is all way amazing.

Best regards,

Doug
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