Tag: print quality

Static and Inkjet Printing on Bottles

Published on by johnball2014Leave a comment

One of the biggest issues in winter, besides being cold, is static.  An outside sales representative was responsible for selling and servicing industrial inkjet printers.  He started to receive more complaints about the quality of the print, especially from customers that used plastic bottles.  This customer was printing a date code on the outside of a soda bottle prior to packaging.  They noticed that the print on the back side was blurry and could be rejected by their distributor.  We discussed how static can cause issues like this with printers.

We had a good discussion about how to solve their problem because EXAIR is the leader in Static Eliminators. The quality of the image is based on the dots per inch, or DPI.  With very fine droplets, static charges can affect the “landing” area of the small droplets.  For the application above, the plastic bottles were generating static charge by bumping and rubbing against each other.  A static voltage is generated in either positive or negative charges.  The stronger the charge, the stronger the force.  To measure the static charges, EXAIR does offer a Static Meter to quantitatively measure the amount of voltage of the static surface. 

Static

With a decrease in the moisture that is present in the air, static charges are able to build easier and to a much higher level.  Material is the other condition for static generation.  The type of non-conductive material will determine how easily it will pass or except electrons.  The soda bottles above are made from polyethylene terephthalate, or PET.  This material has a moderate ability to generate static electricity.  But the charge was enough to affect the print quality. 

Ionizing Bar
Low cost Ionizing Bars eliminate static cling.

                With the nature of static elimination, we want to target the affected area.  In this instance, it was just before the inkjet printer.  I recommended the model 8003 Gen4 Ionization Bar with the model 7960 Gen4 Power Supply.  The EXAIR Static Eliminators are able to produce both positive and negative ions to neutralize any type of static.  They were able to mount the Gen4 Ionizing Bar alongside the bottle near the print area.  After they added the Ionization Bar, the static was removed and the date code printing was clear.  They were so impressed that they contacted the manufacturer of the inkjet printer to have this as an option for similar applications.  Static is a nuisance, and EXAIR has nine different types of Static Eliminators to handle industrial areas as well as labs and clean rooms.  If you are experiencing static issues, you can contact EXAIR and speak to one of the Application Engineers.  We will be happy to help you select the best solution for your static problems.    

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

Gen4 Static Eliminators Sove Static Problems for Printing Co.

Published on by johnball2014Leave a comment

When the weather gets dry and cool, static can be generated very easily, and it can become a real nuisance.  For the printing industry, static forces can pull or push the ink droplets which can create poor print quality like “ghost” images.  Static can also cause contamination to “stick” to the surface of the sheets affecting the printing process.  This can slow production, generate high scrap rates, and allow for poor quality.  In this blog, I will share the details about a printing company having static problems and a simple solution with a Gen4 Static Eliminator.

For this printing company, static was causing issues in print quality on their polypropylene sheets. Polypropylene is a non-conductive material which can generate high amounts of static that can cause many issues.  Their manual operation of moving, sliding, and picking up of the polypropylene sheets was generating the static.  Now that we found the cause, I had to determine a solution.

They sent pictures to describe the process in more detail.  An operator would pick up a sheet with the dimensions of 3 feet wide by 5 feet long (0.9 meters by 1.5 meters) from a bin.  He or she would load three polypropylene sheets onto a wide vacuum table next to the printing machine.  The table had an indicating bar which used yellow/green lights to align each sheet.  Once the indicator lights turned green, this meant that the sheet was aligned properly, and the operator would then hit a switch.

A dual rail with vacuum cups would come over and “grab” the three sheets.  The vacuum rail would pull the new sheets onto a sliding platform at the same time removing the printed sheets into a stacking area.  With the new sheets, this sliding platform would travel into the print machine where the print head would create the images.

Once the printing was completed, the sliding platform would come back to the original position where the process would repeat itself.  With all the handling and moving of the polypropylene sheets, static was being generated.  To improve their printing process by removing the static, we had to target an area where we would not have to worry about static regenerating.

EXAIR is a leading manufacturer of Static Eliminators, and we had a good discussion in solving his issue.  Ideally, we want to place the Static Eliminator just before the printing process.  In this application.  I recommended to them to locate a Gen4 Ionizing Bar just behind the indicating bar.  This would remove any static as the sheets were going onto the sliding platform.  Since the sheets were 3 feet (0.9 meters) wide, we needed to cover a span of 9 feet (2.7 meters) total.  Believe it or not, EXAIR manufactures and stocks an Ionizing Bar this long!!!

For this customer, they would not have to worry about any stop gaps in coverage with a single length product.  Also, the profile for the Gen4 Ionizing Bar is very thin and would not interfere with the vacuum rail system.  So, when the vacuum rail picks up the polypropylene sheets, the Gen4 Ionizing Bar will be able to remove the static from the printable surface.

Gen4 Ionizing Bar with 7960 Power Supply

I recommended the model 80108 Gen4 Ionizing Bar with the model 7960 Gen4 Power Supply.  This model can emit ions that can cover a span of 108 inches (2.73 meters).  The Gen4 Power Supply, which generates a 5,000 Volt signal, connects to the Gen4 Ionizing Bar with an electromagnetically shielded durable cable.  The alternating current generated by the Power Supply allows for the creation of both positive and negative ions from each point.  This will ensure neutralization of any type of static.

The Ionizing Bar can be positioned between 0.5” (13mm) to 2” (51mm) from the sheet surface to optimize decay rates.  After they mounted and started using the Ionization Bar, the static was removed quickly, and the printing issues were eliminated.  With a quick and simple set up of the Gen4 Ionizing Bar, they were able to get back on track with great quality and fast productivity.

If you have static issues with your printing process, you can contact an Application Engineer at EXAIR.  We will be happy to make your static issues disappear and your vibrant images reappear.

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