How to Properly Understand Outdoor Advertising Printing Inks?

Many printing companies use outdoor printing inks daily, so they are quite familiar with them and have a certain understanding of the inks. However, in our actual communication, we have found that many printing companies actually have limited knowledge about the inks, and there are even many misconceptions. They generally believe:

  1. The current ink production technology is very advanced, and the inks are stable, so there should be no issues such as clogging or color deviation during usage.
  2. Nowadays, printers are equipped with micron-level filters, so large particles and impurities in the ink cannot enter the print head, thus preventing problems from occurring.

Is this really the case in reality?

This is actually a significant misconception about outdoor printing inks!

Below, we will conduct an objective analysis of the Raw materials, Formulations, Production Processes, and Performance Characteristics of outdoor inks.

We know that in order to meet the requirements of outdoor durability, water resistance, lightfastness, and resistance to fading due to acid and alkali exposure, outdoor inks can only be pigment-based inks (commonly known as solvent-based inks, oil-based inks, or weak solvent-based inks).

These inks are composed of pigment particles, solvents, dispersants, stabilizers, UV inhibitors, and other materials mixed together. Since this mixture is physical rather than chemical, regardless of how unique the formulation is or how advanced the production process is, it cannot maintain long-term stability.

After a certain period of time, the mixture will undergo separation, resulting in ink layering and precipitation. Moreover, as soon as the ink is produced, this layering and precipitation phenomenon gradually occurs, although it has not yet reached a state where it cannot be used.

The only difference between inks from different manufacturers lies in the length of time they can be stored. High-quality inks can still be usable after 2 to 5 months of storage, while low-quality inks may only last around 1 month.

Some people believe that grinding pigment particles into nanoparticles of 100-200 nanometers (i.e., 0.1-0.2 micrometers) will solve all problems.

However, this is a significant misconception!

Although pigment particles may be ground to such small sizes, it doesn’t mean there won’t be any issues. Due to the attraction of charges, even extremely small particles will aggregate upon contact, leading to clustering that is difficult to separate.

Therefore, although the pigment particles used may be 100-200 nanometers, the size of the ink particles produced is typically 1000-5000 nanometers, not 100-200 nanometers! In other words, after aggregation, the pigment particles in the ink are not uniformly sized but vary greatly in size, with differences of about 50 times.

As a result, once the pigment particles in the ink aggregate to a certain extent, they will begin to settle down, leading to layering and precipitation.

Some people believe that printers are equipped with filters that prevent large pigment particles and impurities from passing through, so ink precipitation won’t cause clogging or damage to the print heads.

However, this is a misconception resulting from a lack of understanding of filters and the form of ink precipitation, leading to a misguided assumption. In reality, filters only have a limited effect in filtering out rigid impurities, but they are not entirely effective. Under pressure, even rigid impurities larger than the filter pores can pass through due to compression and deformation.

Importantly, filters have little effect on large aggregated pigment particles in the ink. This is because aggregated pigment particles form soft clusters, which can easily pass through the filter even if they are several times larger than the filter pores, as their shape can change under slight external force.

In fact, the precision of the filters in printing machines is generally around 5000 to 10000 nanometers, making them ineffective in filtering pigment particles. In reality, pigment particles cannot be filtered out; otherwise, there would be issues with ink concentration.

Therefore, aggregated pigment particles can easily form ink sludge in the ink tube, causing poor ink supply, and can lead to nozzle blockage, causing print head clogs.

Due to the necessity of outdoor inks being pigment-based and the objective existence of the aforementioned characteristics of pigment-based inks, phenomena such as pigment particle aggregation, ink layering, and particle precipitation are inevitable.

This, in turn, leads to various issues such as uneven ink concentration, color deviations in printed images, and clogging of printing machines.

These issues are not caused by ink manufacturers, machine quality, or filter manufacturers but rather stem from the inherent characteristics of outdoor inks.

Contact Us

Contact Us
*We Respect Your Confidentialty And All Information Are Protected
Scroll to Top