Printing These 10 Signs You Have Viscosity Related Questions

Even under the best of circumstances, (new gearless high-speed press, well-trained and dedicated press, atmosphere-controlled environment, very good ink suppliers, etc.), you can still have printing problems.

Many of these problems can be related to ineffective viscosity measurement and control. 

Here are 10 common symptoms associated with insufficient viscosity control:

1. Color change or change during printing : Since color depends on viscosity, measuring and maintaining fluid viscosity throughout the printing process is of great importance to ensure consistent color. Manual control or "spot checking" during a run does not allow true viscosity/color control.

2. Excessive ink usage during printing : With manual viscosity monitoring, the viscosity of the ink can fluctuate greatly due to the many other functions the operator is responsible for. This results in inks being checked and adjusted only occasionally. As the solvent evaporates, the viscosity of the ink increases and more ink is applied to the substrate.

3. Using too much solvent, amine or extender during press operation : With manual control, it increases the possibility of adding too much solvent or amine when dosing. This casual approach will definitely affect the color of the ink. Also, since these additives are poured in rather than metered in, there is limited control over the amount used.

4. Dirty prints or ink smears : If the ink viscosity is not adequately maintained throughout the printing process, the ink viscosity will rise and fall due to solvent evaporation and replacement. Ink can stick or build up on plates, impression rollers or substrates outside the impression area. This can cause smudges or blurring in non-image areas.

5. Blockage of the anilox unit : This can cause printing-related problems such as warped spots, dirty printing or other defects. This is usually caused by improper maintenance of viscosity. Improperly maintained or poorly mixed inks can cause ink solids to become trapped in the cells of the web sample, resulting in print defects. In addition, ink viscosity directly affects the transfer of ink from the anilox roll to the plate. This changes the amount of ink applied to the substrate, which changes the color and intensity of the image. This is why many printers use different anilox rolls at different times of the day or year.

6. Job rejections due to print-related issues : For most companies, “branding” is one of their important marketing tools. Anything related to it came under greater scrutiny, and the expectation of higher quality print work became the norm. If the branding-related colors are incorrect or if there are any printing-related defects, the chances of rejecting the job are higher. Often, these rejections or customer returns can be traced to inconsistent ink viscosity.

7. Excessive cleaning time due to ink-related issues : If there are management issues around the ink tank and throughout the press, there may be a viscosity-related issue. Ink management, including viscosity control and mixing, can help ensure fewer ink sagging problems. Usually, this sling is caused by thin ink or buildup due to an out-of-range viscosity.

8. Press STOP during a run to resolve cleaning-related issues : Proper ink management can reduce the number of times a print needs to be stopped to clean plates, rollers, or other print areas during a run due to ink buildup or flicking.

9. Adhesion or peeling problems : When maintaining ink viscosity manually, there is a risk of adding too much or too little solvent to bring the viscosity back to specification. Also, if different solvent mixtures are used for different inks, there is a chance of adding the wrong solvent, which could cause ink contamination and cause other problems.

10. The ink cannot be dried or dried too fast : When manually measuring and controlling the ink viscosity, the ratio of ink to solvent may not be consistent with the amount of ink used. This can cause the ink to dry too quickly or not fast enough. Variations in ink drying time can lead to a variety of print-related issues, including inconsistent color, bleeding, smearing and peeling. Each of these can cost valuable time, labor and lost income due to rejection.

Ink viscosity is one of the most important elements in any printing process. If you experience any of these symptoms, ink viscosity is probably the first and easiest place to start investigating.