Solving Static and Increasing Print Quality on Food Packaging

Gen4 Static Eliminators

A yogurt company printed bar codes on every cup that they produced. This was necessary for registering and tracing their product. After failing a bar code reader quality test, they started noticing some print issues during batch runs. They would have to stop their system, clean the inkjet printer head, and scrap product that would not register with the bar code reader.

This affects production rates, scrap rates, and overall cost. They stated that they threw away 30 to 40 cases per batch of yogurt due to this problem. They had an EXAIR catalog where they found a similar application within our Gen4 Static Eliminator product line. They contacted us to see if we could find a solution.

With non-conductive material like plastic, static is easily generated; especially during cooler weather. Static can be in a negative state or a positive state dependent on the material. For opposite charges, things are attracted to each other and will “stick” like magnets. For similar charges, they will repel each other. The higher the static charge, the stronger the force.

For the company above, the yogurt cups moved along a 7” (178mm) wide conveyor before they reached the bar code printer. This movement causes static to be generated on the surface of the cups. But, what about the inkjet printer? The function of the printer charges the ink droplets for direction and positioning. Since the ink droplets and the cup surfaces have the same charge, the droplets were being “pushed” back toward the printing head (reference photo below). Thus, the ink would dry on the surface and affect the quality of the bar code.

Bar Code Printer

When it comes to removing static, EXAIR is a leader in this market. We have a large product line of different types of Static Eliminators. Our design generates both positive and negative ions to remove any type of static charge. Since we only had to remove the static from the surface of the cup, I recommended a Gen4 Ionizing Bar. With a quick static decay rate, we can remove the static right before the bar code printer with only one Gen4 Ionizing Bar. For this application, I recommended the model 8003 3” Gen4 Ionizing Bar and a model 7960 Gen4 Power Supply. Together, it was very easy to mount and start using. EXAIR stocks lengths from 3” (76mm) up to 108” (2743mm), and we can ship a solution the same day. When you are losing 30 to 40 cases, time matters. And for this company, they received the items the next day to correct the misprints and short printing runs.

Gen4 Ionizing Bar w/ power supply

When problems occur, time can be of the essence. This is why EXAIR stocks our cataloged items for fast delivery.  For the company above, they had an EXAIR catalog which helped them to find a solution. If you would like to have an EXAIR catalog, you can click here to get one.   After they started using the Ionization Bar, the static was removed, the bar code was clean, and the operation ran smoothly. If static is causing issues for you, you can contact EXAIR and speak to one of our Application Engineers. We will be happy to assist you.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

EXAIR Eliminates Static – Public Enemy Number one in the Printing Industry

Static electricity is the enemy of the printing industry. Downtime and inefficiency caused by static means longer lead times and angry customers! EXAIR can remove static electricity in the many printing applications across wide and narrow webs.  With our rugged line of EXAIR Super Ion Air Knives and Ionizing Bars, EXAIR can improve your efficiency and printing quality.

Digital printing dries out the printed substrate, creating high static charge that can cause printing defects, ink overspray, and even print head clogging and print head shorting issues. If a press is printing on non-porous substrates like plastic, metallics and highly coated glossy papers, a device called a corona treater is used to increase the surface energy of the substrate to ensure the ink droplets adhere and do not spread too much on the substrate. A byproduct of the corona treatment is static charge, which must be removed. This can be achieved by installing an EXAIR Ion Bar after the corona treatment device across the web.

Static is also created anywhere in the printing or finishing operations where sheets are moved over each  other.   Sheet-fed presses, for example, create friction in the stacking of individual sheets on top of each other.  This friction induced static creates misfeeds, print registration issues, multiple sheet pickups and equipment jams.

Folding operations cause static issues too. Like a sheet-fed press, static is created by folded pieces being dragged across each other.

In both cases, installing an EXAIR Super Ion  Air Knife or Ion Air Cannon that can direct a stream of ions between the stack and the top sheet can eliminate the static that causes misfeeds and jams.

The typical easy fix printers employ is what’s called a tinsel bar. Also called garland, it looks just like what you drape on a Christmas tree, except that it’s made of highly conductive copper that needs to be grounded to the printing press.The problem with tinsel bars is that although they are cheap initially, they don’t last long. They’re not a set-it-and-forget-it solution. The sharp strands work on induction and interact with the static field on the substrate creating a neutralizing cloud that surrounds the area, reducing both positive and negative ions. Printing operations are usually dusty environments and when the tinsel becomes dusty, oxidized, or matted and crumpled, they don’t work as effectively.

Static is also created in unwinding and rewinding operations, when rolls are slit to needed widths of various presses. The removal of the web from the roll creates static charge that attracts dust to the substrate surface and can cause major problems in downstream printing operations. Installing an EXAIR Ion Bar on top of the web can eliminate this static.

EXAIR Super Ion Air Knives don’t need to be placed close to the surface like a tinsel bar. Static dissipation of 5 KV can occur in less than a half second up to 20 feet away and can be adjusted from a blast to a breeze, depending on static level.

If you are a printer, finisher or labeler, EXAIR has a static elimination product that can improve your operations. For more help you can contact one of our EXAIR application engineers to talk you through a solution.

Dann Woellert
Application Engineer
dannwoellert@EXAIR.com
@EXAIR_dw                    

 

 

 

EXAIR Gen4 Ionizing Bar Removes Static From Corona Treated Plastic

If you want to print on plastic, it’s challenging – most plastics are chemically inert and non-porous.  That means you can apply all the ink you want; it’s not going to stick.  In the 1950’s, a Danish engineer named Verner Eisby experimented with various techniques to overcome these challenges.  He found that exposing the surface to be printed on to gas flame or sparks modified the surface to improve adhesion with the ink.  It did so, though, in a crude & uneven manner, leaving imperfections & inconsistencies in the printed product.  He then tried applying a high frequency corona discharge in a linear array.  The plasma (gas in an ionized state) generated left a homogeneously treated surface on which to print, smoothly & evenly.

This has become the “industry standard” for many of the labels we see on commercial products, from shampoo & wine bottles on the grocery store shelf, to pennants & banners at public events.  It also leaves the surface even more prone to picking up a static charge from rolling or unrolling, stacking, sliding, etc.

One of our customers makes a great many labels for all kinds of these commercial products, and uses an EXAIR Gen4 Ionizing Bar immediately prior to the printing operation:

Model 8024 24″ Gen4 Ionizing Bar removes static from Corona treated plastic label film.

EXAIR Corporation has a variety of Static Eliminator Products to fit most any industrial or commercial application.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Static Elimination Improves Credit Card Printing and Production

PVC Base Sheet for Credit Cards

A company that made credit cards was having issues in their print quality, and static was the culprit.  They used PVC sheets as a base material to print on, and like with any non-conductive materials, static can be generated easily and create problems.  For this company, static was attracting dirt to the surface of the material, causing blemishes in the print.  They contacted EXAIR to find a solution.

When non-conductive materials slide, hit, peel, and rub; electrons from the surface can move from one atom to another; thus, creating static.  The type of material and the amount of movement governs the amount of static forces.  These strong static forces can attack debris and fibers, as well as generate shocks, misalignment, and machine jamming.  Another feature of static is that it can regenerate if the materials continue to slide, hit, peel, and rub.

For the company above, they were printing on 30 cm by 48 cm (12” X 19”) PVC sheets.  They used three different processes to print a complete credit card; silkscreen, digital, and offset.  After each printing process, they would lose sections of the sheet due to poor image quality.  At the end, they were losing between 20 to 30% in visual rejections.

For this application, we had to do two operations; remove the static and clean the surface from debris.  The Gen4 Super Ion Air Knife can do both of these operations at the same time.  With the laminar air stream that comes from the Super Air Knife, it can carry both positive and negative ions from the attached Gen4 Ionizing Bar.  Together, they can remove any type of static charge as well as becoming a very effective tool as a non-contact wiper to remove debris.  With this ability, the print quality would not be affected during cleaning.  Since static is a surface phenomenon, I recommended to also remove the static from the other side of the sheets.  We did not want to have any dirt or debris that could be remaining on the bottom surface to transfer from one surface to the next during stacking.  This could scrape the finish during loading and unloading of the sheets.

I recommended two pieces of a model 112012 Gen4 Super Ion Air Knives that are manufactured to 12” (30 cm) in length.  This customer can easily mount one above the sheet and one below the sheet prior to printing.  To operate the attached Gen4 Ionizing Bar, EXAIR offers two types of power supplies, a two-output unit, model 7960, and a four-output unit, model 7961.  They can save you money when needing multiple Static Eliminators to operate in your system.  With a model 7960 Gen4 Power Supply, they now had a system to remove static and clean the sheets.  Once they installed the Gen4 Super Ion Air Knives onto their system, the rejection rate dropped to near zero.

All EXAIR Gen4 Static Eliminators use one of two Power Supplies – your choice of the 2-port Model 7960, or the 4-port Model 7961.

Rejected parts are costly, wasteful, and reduce production rates.  If you have rejection from static problems in your system, EXAIR has a large line of Static Eliminators to help you.  You can contact an Application Engineer to review your application.  For the customer above, the Gen4 Super Ion Air Knives made it possible to generate more credit cards per sheet.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb