Printability and use of ink cleaners

Printing aids refer to printing devices that use a small amount, but have a great influence on printing quality and stability, such as printing rollers, blankets, printing solutions, and ink cleaners. This article will focus on the printability and use of ink cleaners.

At present, many domestic printing companies only consider the absolute cost in front of them and still use gasoline or kerosene to clean the ink. This process has already had a significant impact on the social benefits and production efficiency of the printing industry and must be changed. In addition, in terms of roller maintenance, many manufacturers are currently doing marketing work in this area. Now many printing companies, especially in the coastal areas, have paid more and more attention to the important role of maintenance on printing efficiency, so the quality ink cleaner has a broad Expansion capacity. The principle of cleaning the ink cleaner With the increasing demand for printing quality, ink cleaners, which are easily ignored, have a greater impact on printing. Many of the quality problems that occur in printing are often directly or indirectly caused by ink cleaners. For example, the rubber rollers carry water or ink with low performance, the rollers are deformed, the density in the field is insufficient, and the flat screens are distributed, mostly due to cleaning. Improper use of the agent leads to problems with the roller, which affects the print quality and increases the downtime of the print.

In the process of cleaning the ink, using the principle of emulsification, use a high-quality ink cleaner and water for cleaning. Cleaners can dissolve oil-soluble substances, water can dissolve water-soluble substances, form "oil-in-water", "oil-in-water" form to complete the cleaning of the surface of the printing roller, can clean most of the oil-soluble and Water-soluble substances. However, each cleaning cannot completely remove the impurities on the surface of the roller, there will always be some impurities left on the surface of the roller, and this also needs to be differentiated according to the nature of the ink, if you print gold and silver and other spot color inks, clean Work will be more difficult.

Composition of ink cleaners

1. Hydrocarbons

In cleaners, the content of hydrocarbons is more than 50%, and hydrocarbons are divided into aliphatic hydrocarbons and aromatic hydrocarbons according to the molecular structure. They have the following characteristics:

(1) Aliphatic hydrocarbons: The chain structure containing carbon molecules in the molecule has a good dissolving effect on the ink and cannot be dissolved in water. It does not harm the rubber, the human body and the environment.

(2) Aromatic Hydrocarbons: The cyclic chain structure of carbon molecules contained in the molecule has a good dissolving effect on the ink, but it will cause swelling of the rubber polymer, and at the same time it will have an adverse effect on the human nervous system. Long-term use may result in Cancer lesions.

2. Emulsifier

Ink cleaners must contain emulsifiers that have the following properties: they promote the mixing of oil and water and produce emulsification; general flash point cleaners contain emulsifiers; they do not cause chemical crystals to remain on the rollers and the blanket.

3. Anti-corrosion agent

Because the cleaner needs to be cleaned with water, the anti-corrosion agent has the effect of preventing water corrosion.

High-quality ink cleaners generally consist of two organic solvents with different boiling points, rubber antioxidants, and surfactants that can form stable water-in-oil emulsions.

Ink cleaner technical indicators

In general, the technical indicators for measuring high-quality ink cleaners are:

1. Fragrance-free

Aromatic compounds have a strong ability to clean inks, but aromatic compounds have a number of adverse effects on printing, so new ink cleaners should not contain aromatic compounds.

The adverse effects of aromatic compounds on printing are:

(1) Fragrances can cause rubber swelling, affect printing pressure, and can easily cause print quality problems.

(2) Does not meet environmental standards and human health standards.

2. Base vegetable oil

Ink cleaners should be based on vegetable oils, not mineral oils.

3. High flash point characteristics

At present, the flash point of international high-quality ink cleaners is above 55°C. In the cleaning process of thermosetting inks, the flash point of cleaners is as high as 100°C or more. The flash point of the cleaner must be higher than the minimum temperature in the print channel to meet the safety standards of the workshop. The flash point of the cleaner in general printing should be above 55°C. In the printing of UV ink, the flash point of the cleaner should be Above 70°C.

Quality ink cleaner characteristics

In printability, high-quality ink cleaners have the following performance:

(1) It meets the requirements of environmental protection and health. It does not contain aromatic compounds and its flash point is higher than 55°C.

(2) The ink has good cleaning ability, and the degree of cleaning of organic and inorganic compounds is more than 95%.

(3) Good adaptability to the rubber roller and rubber blanket, and the expansion rate generated is not higher than 2%.

(4) No corrosive effect on printing plates and printing presses.

(5) The main component of auxiliary cleaners should be vegetable oil.

Ink roller auxiliary cleaning

In the printing process, due to the influence of external conditions such as paper, ink and water quality, the cleaning effect of the ink, the chemical adaptability of the printing roller, and the influence of deformation due to chemical factors are increasing. In modern printing, we also use some chemical care products for auxiliary cleaning while using ink cleaners to ensure that the impurities remaining on the rollers are completely removed, and the purpose of smooth printing is finally achieved. These auxiliary cleanings mainly include deep cleaning, enamel removal, rubber reduction, idling protection, and dead ink softening.

1. Deep Cleaning

Mainly in the printing unit replacement color, ink roller cleaning and maintenance and printing spot color ink when carried out, can significantly reduce downtime and reduce the number of paper.

2. Calcium removal

The quality of the water supplied to the lithography printing system in different regions is different. The calcium carbonate and other minerals contained in the system are also different. At the same time, the water hardness varies. Under normal circumstances, the rubber roller will absorb calcium carbonate and other minerals, so that the surface of the roller to transfer water, ink, the ability to decline, so the removal of calcium is very necessary.

3. Idling protection

The contact surface of the ink roller will cause permanent damage to the surface of the ink roller in a very short time when it is rotated without ink lubrication. Therefore, when the ink roller is idling, special chemical care products are needed to prevent the ink roller. The idling causes surface damage or excessive heat.

4. Regular cleaning

Long-term printing will cause stubborn hard ink and other impurities inside the rubber, which will cause the glaze and hardness of the surface of the rubber roller to increase. Therefore, the rubber must be thoroughly cleaned and elastically restored.

5. Enamel removal

Due to the accumulation of time, the residual material formed on the rubber surface must be cleaned.