Struggling To Overcome Production Challenges? It Might Be That Tiny Static Electricity Is Causing A Big Problem!

In the production of self-adhesive labels and the labeling process, static electricity is almost everywhere, which brings great trouble to our label printing enterprises. Especially with the advent of winter, the air humidity gradually decreases, and the "static electricity problem" in the printing process is more obvious. How does the static problem arise? What are the common label printing problems? How to eliminate static electricity? In this article, let's talk about it together.

The generation of static electricity problems

Normally, various materials have the same number of positive and negative charges, and the positive and negative charges neutralize each other, so that the material itself does not show electrical properties. However, if the material absorbs additional electrons from the outside world, it will present a negative charge. Conversely, if some electrons are lost, the material will present a positive charge. Both of these methods can be called electrostatic effects. Combined with the actual production environment, the generation of static electricity is mainly due to the contact and separation of two materials of different materials, the loss and gain of electrons one after another, and the electron transfer within the material, resulting in the electrostatic effect.

Specific to the label printing production process, theoretically, static electricity will be generated in the place where there is friction separation in the production process, such as the unwinding and unwinding place, the position of the pressing roller, the position of die-cutting and waste discharge, the position of lamination, the position of labeling, etc., all of which will generate static electricity. Therefore, static problems can accompany the entire life cycle of the label, from material unwinding, printing, die cutting, winding to final use.

External influencing factors of static electricity

The external factors that cause static electricity mainly include environmental humidity, raw material performance and printing equipment itself.

01. Ambient humidity

In winter, the ambient humidity decreases, and the surface resistance of objects increases with the decrease of humidity, resulting in static electricity problems.

02. Raw material performance

Under the same environmental conditions, film materials are more likely to generate static electricity problems than paper materials, because film materials themselves are insulating, and once static electricity is generated, it is difficult to conduct positive and negative charges like paper materials.

03. Equipment itself factors

The antistatic ability of the equipment itself is also an important influencing factor. The grounding situation of the equipment directly affects whether the static electricity can be smoothly exported after it is generated. If the surface of the transmission roller is flat and smooth, the static electricity generated will be relatively less, conversely, if the surface of the transmission roller is rough, worn or stained, the generated static charge will increase.

Hazards caused by static electricity problems

01. Glitch phenomenon

During the printing process, if static electricity is generated during the contact and separation between the printing plate and the ink roller, the edge of the pattern text will fly out due to adsorption, forming an ink whiskers, similar to burrs.

02. Electrostatic markings

When printing on the spot, there are markings, which look similar to poor ink fluidity and uneven inking, but in fact, the ink has been affected by static electricity before drying, resulting in displacement.

03. Missing seal

The two colors of ink printed on top of each other will produce white edges of ink that cannot be printed between the colors due to electrostatic repulsion, such as the gaps of rejection in the place where the white ink is laid around some text.

04. Dirty spots

If the static electricity carried by the raw material is large, it will adsorb the dust in the environment, leading to the appearance of printing dirty spots, white spots, and fisheye problems.

05. Electrostatic adsorption

During single material printing or single label collection, electrostatic adsorption will cause the material and label to be unable to separate normally. During the labeling process, the label is affected by static electricity, and after peeling off from the bottom paper, it will be irregularly adsorbed on the bottle body, causing the label to wrinkle and blister.

Printing static elimination method

After static electricity is generated, you can use an electrostatic tester to test the magnitude of static electricity. The operation method is to use the test port of the electrostatic tester within 150mm of the material, and the real-time static value can be detected. Let's take a look at what methods can reduce or eliminate printing static electricity.

1. Physical elimination method

Uses the physical properties of static charges to eliminate static electricity. There are two main methods: grounding elimination method and humidification elimination method.

Grounding elimination method: By using metal conductor materials, one end touches the printed material, and the other end is connected to the grounded equipment to direct the static charge to the earth, thereby eliminating the static charge present in the equipment. At present, the common grounding methods in printing factories are mainly added to remove static rope and remove copper wire. In contrast, because the electrostatic copper wire is exposed in the air, it is easy to cause oxidation and weaken the conductivity, while the highly conductive copper wire of the electrostatic rope is wrapped in nylon, which has a better antistatic effect.

Humidification elimination method: reduce the resistance of the surface of the substrate material by increasing the ambient humidity, and the increase of ambient humidity will also improve the conductivity of the material surface, thereby reducing the static electricity problem. In addition, the increase in ambient humidity can also reduce floating objects in the environment, and will also greatly reduce the dust problem. At present, the simplest way to humidify is to mop the floor frequently, but it is more recommended to use a spray humidifier to humidify the overall workshop environment.

2. Chemical elimination method

By applying a layer of antistatic agent coating on the substrate, the substrate material conducts electricity, which can also effectively reduce the generation of static electricity. This method can be used both before printing and by adding an antistatic agent to the varnish and using it after printing.

The above is a brief discussion of the causes, hazards and solutions of printing static electricity, hoping to help label printing companies that also encounter similar confusion in the actual production process. In short, the simplest solution is to directly seek anti-static raw materials or improve the grounding of equipment and ambient humidity to reduce or eliminate static electricity troubles.