Web press tension control can be a real source of grief.  Thankfully pressmen have a few principles that can apply to almost any web offset printing press.  Though there are exceptions the rule, I would like to share those principles that may help you to get control of web tension on your press. How Web Press Tension Works Though a web offset printing press prints on one continuous roll of paper, each part of the press is not running at the same speed.  In order to maintain tension, each component has nip points that drive the web at different speeds in order to control web tension.  These differences are marginal, but crucial for each part of the machine to be able to perform its function.  The number is carefully calculated according to a reference. The Reference The speed of each part of the web press is referenced to the printing units.  These are the most critical "nip points" on the press and everything else must work around them.  Much care is taken so that the

UV Curing has definitely found its niche in the offset printing market and there are plenty of suppliers out there (ex. Eltex , Prime UV , GEW , and IST  to name a few)  In this entry, I give you the perspective of a pressman who has actually seen a UV curing system integrated onto a coldset offset printing press.  Coldset printers who want to start competing in the heatset printing market can make quick inroads with comparatively small modifications to their press line and this was no less true for our company.  There are however some realities that you must be aware of from an operational standpoint. Why Some Purchase A UV Ink System What you will hear when debating whether to purchase this system is the cost analysis perspective.  Is it worth it to make the comparatively small intitial investment of purchasing a UV drying system as opposed to buying a heatset oven ?  This is a complicated analysis and I do not offer such in this entry.  What I can tell you is what we have e

A press operator is a loosely used term to describe someone who works on an offset printing press.  It is first of all important to understand that there may be several designations of pressmen in any given setting.  For example, one print shop may have a smaller sheetfed press which requires only one press operator, while another uses a large 16 unit coldset web press requiring multiple press operators.  The job descriptions may be broken down into different positions on the press. Job Description Breakdown For Every Position 1.  Press Operator .  Also known in many shops as the Head Pressman, First Pressman, Lead Pressman or Supervisor.  Responsible for overall operation of the press. 2.  Operator Assistant .  Many shops will call this person the 2nd pressman.  Others may use the term Ink Adjuster or Colorman.  Whatever the case, this one is usually responsible for everything to do with the inks and filling in for the Press Operator when he is absent. 3.   Rolltender .  An

Modern technology has produced some extremely fast printing presses.  Here is a list of the five fastest offset printing presses in the world.  They all produce over 20 finished magazines or newspapers every second.  If we get technical, deciding which press is truly the fastest is quite subjective as my conclusion shows, but here are a few definite contenders. 1.)  Man Roland Lithoman - 100,000 Copies Per Hour Copies per second: 28 Web speed:  3000 fpm Cylinder revolutions per hour: 50,000 Capacity: Double circumference / double width Though some printers have removed the governor and made it go a little faster, here is a video of one in production at 100,000 copies per hour. 2.  Goss 3000 Sunday Press - 100,000 Copies Per Hour Goss Sunday Press Copies per second:  28 Web speed:  3,000 feet per minute Cylinder revolutions per hour: 50,000 Capacity: Double circumference / double width / gapless / pinless folder Since inheriting a fantastic product from Heidelberg, Gos

Let me start by a qualifying statement.  I am not German, I simply state a fact.  I have worked on the following equipment: Goss , Mitsubishi , Heidelberg , Man Roland , Harris, Miller, and News King.  Some of those presses I am more proud to have worked on than others simply because of the quality of how they were made.  So there is something that must define why Germany continues to dominate the printing industry since the days of Gutenberg .  Here are some reasons to consider. 1.  History.  Gutenberg was of course German.  Somehow it is still in the roots of the German psyche to print.  Starting from Gutenbergs press in Mainze, Germany, printing spread throughout Europe and to the rest of the world.  Notably, it was not inventors from other countries that came up with similar inventions ( though this can be debated ), but rather Germans travelled to other countries and introduced the idea.  German innovation spreads in the same way today. 2.  Innovation.  Take a look at

Dot gain is one of the most discussed variables in offset printing.  To accurately produce four color images, dot gain must be controlled.  There are many explanations, but I would like to present one in very simple terms before I get into a subject like this in depth.  Let's start by answering a couple of simple questions.   Dot gain occurs when image is transferred (right) What Is Dot Gain? As shown in the picture above, dot gain incurs a loss of quality and "fuzzy edges.  The process of transferring causes the dot to increase in size.  But we must understand two different types of dot gain to understand what is happening. Mechanical dot gain How dot gain happens. Mechanical dot gain is when a dot or any printed image is transferred from one surface to another, some  pressure must be applied to perform the transfer.   Let's use an example: I love the example of potato printing from elementary school.  Cut the potato in half and carve an image in

Automatic registration is one of the foremost achivements in automation for the offset printing industry.  Gone are the days when a pressman had to run to each printing unit and manually crank on a shaft or compensator to line up the colors.  Automatic registration has become almost a second thought.  On startup, the press will line up all colors to within hundredths of a millimeter.  Here is a video demonstration of how it works. An Innovative Improvement This gift to pressmen has brought about more possibilities.  For example, many web presses today have an automatic registration system that combats piling.  Small adjustments are made throughout the print run to move the plate cylinders in unison just slightly.  These small adjustments minimize piling problems as no one particular part on the blanket builds up quickly. Some Improvements Yet To Be Made Though these systems are fully automated, there are a few procedures that automatic register has failed to deal with.  I hope we

Though a pressman doesn't need to know everything about how offset printing  blankets are constructed , he should understand a few basic characteristics that affect the printed product.  Here I offer seven properties that directly affect how well a blanket will run on an offset printing press. Tensile Strength Solvent Resistance Caliper Surface Release Compressibility Stretch Squareness Lets explore each of these characteristics one at a time, with particular focus on how it will effect the ability to run on the press and the printed product. 1.  Tensile Strength Blankets should only be tightened around the cylinder with just as much force as they need to not move on the run, nothing more.  The reason being is that the tensile strength, or the ability of the woven fabric to withstand the pull around the cylinder, is only so strong.  The basic idea is to have the blanket stretch as little as possible for two reasons: 1.) The blanket can rip.   2.)   Blanket height