The Offset Pressman

I don't like to promote products, especially ones that are unproven.  But there was a new product released at Drupa by Grafinkontrol for offset printers that I think is going make waves in the industry.  It is an automatic blanket cleaner that uses dry ice (carbon dioxide just like you see above) to wash blankets.  It promises the following three things that together could add up quickly to justify the cost: No emmissions.   Since carbon dioxide occurs naturally in our atmosphere there's no concern about what it gives off.   Solvent free.    This cost savings alone could justify it.  Not only does it require no solvent, but you can now eliminate costs associated with disposing of any waste solvent from your current system. No waste.  That's right, not a single copy is lost on a wash.  Done at full speed. Here's how it works: Dry ice is injected from nozzles onto the printing blanket while running.  The carbon monoxide immediately vaporizes and

I'm not sure about other offset printing processes, but with our press, we use take-off bars, or perhaps some refer to them as run-off bars.  I've never used them on a sheetfed press, but on our web presses they save us major headaches.  I'm not talking about the ones that control ghosting - that's a different subject I've covered .  These are simply strips of printed image along the edge of the running paper.  In our case, they are about 3 mm wide.  The picture below gives you an idea of what we use. The right of the printed sheet shows we print a little ink on the edge. For us, this controls three very important things. 1.  They control ink buildup on the edges. I've worked on 5 different brands of offset web presses.  Four of them we could never get the ink keys on the edge of the fountain to close enough to stop the ink flowing down the ink train.  The problem would be compounded as the ink would continually build up on the edges of the rollers wit

It's a simple test for your offset printing ink that any pressman can do with limited tools.  It will tell you how compatible your ink and fountain solution are.  It will also tell you why you may have scumming problems - or more correctly tinting or toning problems.  It is a test that the chemists at major ink companies such as Sun Chemical or Flint will do and if you would like to speak intelligently with them, they will know this test.  Quite simply, it will help you troubleshoot your in k . The Ink Bleed Test The only things you need to perform this test are shown in the picture above.  Here is what you need: A small sample of the ink you are currently running. About half a cup of your mixed water and fountain solution. An empty plastic bottle. To perform this test, do the following: Cut out the bottom of a plastic bottle (about the bottom 2 inches) Put a small dab of ink in the center of the ink you want to test. Put your current running fountain solution and

I would like to continue the subject of essential tools for a web offset printing press with another device that has proved very helpful for us.  Pictured above is our paper moisture content reader .  As the name suggests, it can tell you the moisture content from a range of 1-15% for whatever paper you are running.  Much has been written about the effect of moisture content , but I would like to talk about one designed specifically for offset printing. How It Works Here is another picture with the lid open.  Notice the winding hollow in the lid (called a wave guide).  A sample of paper that you are running is put on top of this guide.  Upon closing the lid, a microwave signal is sent through it.  Whether the product has printing on it or not makes no difference.  Based on the strength of the microwave signal that reaches the end of the guide, an accurate reading of the moisture content is given.   Tip:   Put four or five sheets in instead of one.  You will simply need t