Important factors of printing quality: environment and climate

Product quality is the key to a company's survival. Only companies with high quality products can be invincible in the fierce market competition. So, what are the factors that affect the quality of printed products? The factors affecting the quality of printed products include: board films, printing plates, development, inks, paper, and printing pressure. The environmental and climatic factors affect the printing quality throughout these factors, so the environment and climate affect printing quality. The good or bad plays a big role. Here we mainly talk about how the environment and climate affect the quality of printed products by affecting the quality of ink and paper.

Influence of environment on gravure ink

1) The printability of the ink is related to the ambient temperature and humidity. Therefore, the choice of the ink must also take into account the differences in the climate, and the ink of the companies in the vicinity should be given priority.

2) The gravure printing process conditions include printing speed (line speed), drying capacity, plate roller performance, gravure printing mode (surface printing, in-print printing), printing color number, printing sequence, ambient temperature, humidity, and the like. Gravure printing process conditions directly affect the ink transfer rate, drying speed, etc., therefore, according to the process conditions, reasonable and economical choice of ink. For example, when the humidity at the production site is high and the printing speed is high, high-grade inks with high transfer rate and fast drying speed should be used to prevent the film from sticking after printing. Under the conditions of air drying and high printing speed, the ink with high viscosity and antistatic agent is used to avoid quality problems caused by static electricity.

Influence of environment on pad printing ink

In general, the ink manufacturer will give guidance on which substrate the ink is suitable for, but this opinion is for reference only. To choose a suitable ink, you need to understand a few things: what kind of substrate to use; whether the substrate needs pre-printing before printing; what kind of color to print; recommended drying or curing of the ink and ink resistance Grinding, chemical resistance, weather resistance and other performance requirements.

In the process of controlling the ink performance, it should be noted that the environmental temperature and relative humidity have a great influence on the ink performance. The higher the temperature, the faster the solvent volatilizes and the faster the ink becomes sticky. However, the two extremes of relative humidity (very high humidity and very low humidity) are not the case. It is difficult for a printer to control ink performance when relative humidity is at two extremes. Therefore, this has always been a problem for printers. Humidity exceeding 80 to 85% will make the ink sticky at a slow rate; and humidity below 15 to 20% will make the ink sticky at a slow rate. However, when the environment is at two extremes, simply controlling the characteristics of the ink solvent is basically incapable of improving the viscosity of the ink.

Environmental and climate effects on labeling inks

First, the impact of environment on the performance of the label ink

1) The effect of the temperature and humidity of the printing shop on the performance of the ink. The viscosity and dryness of the ink are sensitive to the ambient temperature. When the temperature rises, the viscosity of the ink decreases and the drying speed becomes relatively faster. On the contrary, the ink viscosity increases and the drying speed becomes slower. In addition, the humidity of the environment also affects the dryness of the ink. Too high humidity in the workshop is not conducive to the drying of the ink. On the contrary, if the workshop is too dry, static electricity is likely to occur, causing a series of printing failures. Therefore, if conditions permit, it is best to install air conditioning and humidity control equipment in the printing shop so that the temperature and humidity in the workshop can be kept constant to facilitate the stability of the printing process. In general, the temperature of the printing shop is controlled at 18-25°C and the humidity is controlled at 55%-65%.

2) The hygienic condition of the printing shop is also very important. If the hygienic conditions in the workshop are poor, a large amount of dust particles or various foreign particles may fall into the ink tank or adsorb on the surface of the label material, thus affecting the printing quality. Therefore, the printing shop should be kept clean, dust-free and well ventilated and exhausted.

Second, the impact of environment and climate on label ink storage and management

1) It is best to maintain a constant temperature in the ink warehouse, and the temperature difference from the printing shop should not be too different. If the temperature difference between the two is large, the ink should be placed in the printing room in advance, which is not only beneficial to the stability of the ink performance, but also ensures the high efficiency of production.

2) In some areas in the north, the winter weather is relatively cold. Avoid storing the ink outdoors and prevent the ink from gelling at low temperatures. If the ink is gelled, it can be transferred to a warehouse with high temperature, or placed in hot water, so that insolubles can be restored to their original state.

3) The ink also has a certain shelf life. If it is stored too long, various components of the ink formulation may be separated and precipitated under the influence of the environment. Therefore, the ink should not be stored for a long time. The general storage period is about 1 year, otherwise it may affect the printing quality and even cause printing failures.

4) The remaining ink after printing must be sealed and stored in a dark place and can be reused in future production. Before using it again, it must be filtered with a filter of 100 mesh or more, mixed well with new ink before mixing.

Environmental and climate effects on paper

The main component of paper is plant fiber, which absorbs moisture in the air. Therefore, the moisture content of the paper changes with changes in temperature and humidity. Paper moisture content changes, the paper will stretch, and in the process of lithography also needs water, paper and water contact, the water content will be different, the paper size is difficult to maintain the same, and for color printing Speaking, it will result in overprinting. Experiments have shown that a general change in relative humidity of 10% in air causes the paper's moisture content to change by about 1%, and the paper size changes by about 0.1%, which can only control the temperature and humidity of the printing shop and reduce the change in the moisture content of the paper. To control its scaling changes.

Paper is also subject to deformation caused by climate change during shipment, transportation and storage from paper mills. If the water content in the air is less than the moisture content of the paper, the paper edge water will evaporate and evaporate, and the phenomenon of “tight edges” will appear; when the water content in the air is greater than the moisture content of the paper, moisture is absorbed by the paper edge, and the water content in the middle of the paper is small. If the water content is too high, the "foliage" phenomenon occurs; when the water content on the front and back of the paper is not equal, the paper appears "curled. The paper is deformed, which results in misprints and wrinkles in the printing process.

In order to reduce paper failure during printing, the water content of the paper is adapted to the printing requirements, and it is compatible with the temperature and humidity of the printing environment. The plain printing paper generally needs to be subjected to suitable printing processing, and the processing method is preferably to use a paper-making method. The temperature and humidity of the paper and the printing shop are the same so that the moisture content of the paper itself can be maintained evenly.

Reprinted from: Longjiang Printing Network