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Showing posts from April, 2011

How To Make Printing Ink

  Introduction Printing ink is so much more than just the black stuff that you put on a page. It has been around for thousands of years, and it's been used in everything from newspaper presses to digital printers. As you can see, we're not talking about offset printing ink which is oil based. I want to have a little fun and talk about how you can make your own ink for your printer.  At home! Ready? Ingredients You will need the following ingredients: Soot (5 tbsp) : This is as purest as it gest. You can make the soot yourself by holding a glass up to a flame. This will allow you to slowly accumulate the soot. Water (2 tbsp): For the base of your ink, use distilled water so that you don't introduce any impurities into the mix. Distilled water is also easier to clean up than tap water because there are no minerals or residue left behind from tap water. Alcohol (2 tbsp) (grain alcohol): This ingredient works as a preservative for your ink and allows it to last for several mo

How Much Does An Offset Pressman Make?

As an offset printing pressman, what should my salary be in 2020? How much money should I be making?  If your like me, this question about salary pops in your mind every time you get paid.  Probably not enough, right?  I would like to share with you how much the pressman make that I have worked with as well as some factors that make a difference how much they got paid. I have worked in four different pressrooms in 22 years on six different presses.  Though we never openly spoke about it, somehow we knew how much the other got paid.  Additionally, I have friends in the industry who volunteered the information.  Here's how much they made. A first pressman on a web press in the places I've worked in the past 10 years made anywhere from 33 to 39 dollars per hour.  The salary graduated down to barely above minimum wage for the newbie.  Sheetfed pressmen were usually paid in high 20's if they were skilled and worked with four color. Now that raises some quest

How To Troubleshoot Hickeys On Your Press

Left: Hickey on plate.  Right: Hickey on blanket Hickeys are a fact of life in offset printing .  That much I've made peace with.  However left uncontrolled, they cause us massive amounts of waste .  That's why we are constantly trying to troubleshoot and control the sources of offset printing hickeys.  Here are a few sources of hickeys and some methods to solve this problem.  First of all though, let's define a hickey so that we know we're on the same page. Hickeys - What Are They? A hickey is any particle that sticks to the blanket or plate that transfers an imperfection to the printed page.  Usually they are a dot with a ring around it.  Sometimes they are just a dot of missing color.  In any case, there is missing image.  Whether it is around the dot or the dot itself that has not image.  I'm sure that could only make sense to a pressman . Sources Of Hickeys  In my years in printing on sheet fed, heatset and coldset web presses, most of the time a hickey

Scumming – Causes and Solutions

When it comes to offset print scumming , I will assume you know enough about ink and water balance to know how to make it go away.  I would like to go into some of the deeper reasons as to why scumming can happen and what remedies can solve this plague.  First of all, let’s define scumming. Definition In offset printing , when the non-image areas of a plate become receptive to ink, that’s scumming.  Too much ink or not enough water is not a definition.  Those are cause s.  Since the causes are so many, that definition is broad enough to encompass most reasons.  Causes of Scumming Let’s now look at a few causes of scumming beyond the simple ink and water balance solution. Plate is sensitized by piling. Dirty metering or water pan roller. Poor plate development. Poor ink strength. Bad roller settings. The Right Tools You need the right tools to combat this issue. Scumming usually starts invisible to the naked eye. Be sure you

Plate Scratches – What Causes Them?

  Scratches on printing plates happen in our pressroom on a somewhat rare, but consistent basis.  We start up the press sometimes and voila!   There it is.  Other times, they don’t show up until three or four hundred thousand copies.  Most of the time, just looking at the scratch can tell us where it came from.  Let’s take a look at some of the causes and a few preventative measures that we use. Cause #1:  Handling Carts to prevent plates scratches. This is our most common problem.  Plates are sensitive and require careful handling by the pressmen and plate room personnel.  Most of our presses run four color and so just in bringing a set of eight plates from the prepress department to the press can cause abrasion.  We designed carts to transport them and place the non-abrasive sheet that is between the plates back between them for transport afterwards. Additionally, we’ve set a system up whereby after each plate is burned, the prepress person must visually in

How To Resolve Gear Streaks On Your Press

Gear streaks correspond to # of gear teeth. Gear streaks in offset printing occur due to the teeth that drive the printing cylinder.  Bearers are meant to smooth this out, but that is not always the case.  Hence gear streaks.  Whenever we have seen them on our presses, they occur parallel to the cylinder and correspond exactly to the distance between the teeth of the gear that drives the cylinder.  When this happens, we know that either a setting is out or something is worn.  I would like to share a couple of remedies for this problem. Below I list possible causes and solutions according to the order that I would troubleshoot them.  It makes sense to start troubleshooting with the simpler things before getting deep into the problem. 1.  Improper Packing It is quite possible that one of the two cylinders (blanket or plate) is trying to drive the other.  For example, when a blanket is over packed, the circumference of it increases.  This increases the su

How to Control Setoff In Offset Printing

We have a flow chart that our pressmen use and I would like to share it.  We use it for troubleshooting setoff on our offset printing press.  It starts with the simplest solutions and gradually goes to the more difficult.  Of course you really have to be able to examining the setoff to understand where it’s coming from.  However, here is our list of solutions for solving problems with setoff which usually puts us in the right direction. Definition First of all, we define setoff as any ink or combination of ink and paper that remains on the idlers, nips, former board or chopper table on our heatset printing press.  On our sheetfed presses it takes on an additional dimension in that marking or smudging is accompanied by setoff. Bustle Wheels Bustle wheels can cause setoff. I start with this since it’s probably the easiest fix.  If our bustle wheels are not lined up properly, they will cause setoff.  Often we don’t realize it because the web is bounc

Web Break Sensors - How They Work

Web break sensors are primarily responsible for detecting an web break on an web offset printing press.  Let's take a look at different types of web break sensors and the advantages and disadvantages of each. Why They Are Necessary Modern presses today run so fast that by the time a pressman realizes that the web has broken, significant damage can be done.  Therefore a web break sensor will trigger a stop if tripped.   Different Types Photoelectric web break sensor There are several different types of web break sensors.  Most modern presses use a photoelectric sensor .  Here are some advantages of using this type. Easy to mount and position. Generally not effected by heavy ink coverage. Long life. Low maintenance. Some disadvantages to the system may be that it is not able to detect a quick reduction in tension.  At times the web must clear the detector before it is noticed.  However a mechanical web break sensor does not have this problem.  Here are s

Quality Checks - How To Do Them Properly

Offset Printing Quality Check A quality check, also known as a press check, is when a customer comes and wants to see his job being printed.  In my experience it is a good thing when done properly since he will be able to give input into what the final product will look like.  Let's take a look three essentials that will make your quality checks most effective. 1.  Be Present At The Quality Check Whoever sold the job should be present for the quality check.  The sale did not finish when the customer agreed to get the job printed.  The salesman must also sell him on what the final product will look like.  So many times I have seen where the customer is at the press and the pressman is trying to convince the customer about what can and cannot be done.  That is not his job.  2.  Knowledge Of Quality Control Standards In addition, whoever sold the product must be knowledgeable enough of offset printing standards to explain what can and cannot be done on a printing press.

Offset Printing Questions and Answers

Here are a few commonly asked questions by offset printing clients.  The answers are simplified, but will help a pressman and client to effectively communicate in the same offset printing “language”. What is a signature? Printed signature Quite simply, a signature is a single printed product as it comes off the offset press.  A signature will generally consist of several pages and may be in a semi-finished form.  Many products like books consist of many signatures bound together.  The term signature is fitting because just like handwritten signatures by individuals are different, each individual product produced by the press usually has a unit configuration. What is an impression? One full revolution of the offset printing press is one impression.  This is not to be confused with the signature since one impression can produce multiple signatures.  In order to economize, printers will try to produce as many finished products per impression as possible to save press time.  Thi

Plate Wear - How It Affects Quality

Recently our offset press has been having trouble with plate wear after about 300,000 impressions.  Not that the plate wear is significant enough to cause serious quality concerns, but since we have recently been trying to meet ISO standards, it has caught our attention.  After doing research as well, I know we are not the only ones experiencing this in offset printing . Achieving ISO Standards As most who have implemented it know, ISO standards are very strict when it comes to dot gain and loss.  We have been trying to achieve a plus/minus two percent variance.  This has turned up the ante for the pressmen in achieving consistent density.  Since we have a closed-loop inking system, we have managed to keep this controlled in a narrow window. The problem however has arisen now that our plates wear after about 300,000 impression and put us out of tolerance in our 40% screen.  This is in spite of the fact that our plates are rated to last 500,000 impressions. Given that ou

Diseases and Hazards in the Offset Pressroom

Printing Started As A Hazardous Trade Although modern day organizations have make pressrooms safer, there are numerous hazards that plague pressmen in our 21st century.  They're not new to the printing industry, but modern discoveries have helped us to take additional steps to protect ourselves. It started with a man named Bernardino Ramazzini who lived in Italy in the late 1600's.  He was a doctor who studied various diseases affecting workers.  He wrote a book in 1700 entitled, "Diseases of Workers".  He analyzed over 50 "dangerous trades" and in his book he includes that printers were plagued by "unusual lung disorders". Add to this studies that have come out in the past 100 years.  They have continually proven that pressmen suffer from lung disorders.  So the question remains, what is the cause? Emphysema Studies show that pressmen suffer a higher rate of emphysema that most other trades.  The number of chemicals that pressmen

Make Your Offset Press Makeready Faster

If a press isn't running, it isn't making money.  That reality motivates pressrooms to make their makereadies faster and more efficient on their offset presses.  As a pressman of 22 years, I would like to share with you five essential ingredients to making your makeready better.  Each printing press is unique in complexity and size, but these principles will help any pressman to take their makeready efficiency to the next level.  In many ways, you will see it's not much different than a formula one pit stop.  So here goes. 1.  Make A Checklist A glorified makeready. It doesn't matter how wonderful of a pressman you are, no one is perfect.  Forgetting one simple step in a makeready can cause many headaches.  A checklist ensures this doesn't happen.  Make it as detailed as you want, outlining all the settings and adjustments that need to be made.  Moreover, it should tell you in what order they can be done.  The less you have to think all the steps out whe

What Is Offset Printing?

Offset Printing Press Offset printing is a process used to transfer ink from a plate to a blanket and then to a printed surface.  It accounts for 40% of all printed material and is able to reproduce images in very high quantity.  There are many forms of offset printing , but offset lithography is the most common. Offset printing plate loading onto press. The offset printing process itself is quite simple.  With offset lithography, an inking system consisting of rollers touches a printing plate.  Certain areas of the plate are receptive to ink and so the ink adheres to it.  Additionally, by means of a dampening system , water is applied to the plate to bind to areas that attract water.  When the water binds to those areas of the plate, it repels the oil based ink from them.  Thus some areas attract water while others attract ink.  Pressmen work hard to maintain this ink and water balance . The ink then travels to what is called a blanket - a thin rubber layer over a steel