Due to the metal layer on the surface of the gravure printing machine structure and printing materials (aluminized film), it is easy to produce condensation in March to August (rainy season) every year, especially in the south. The condensation phenomenon in the printing process has a great impact on the printing quality control management and printing quality, which directly affects the production of the subsequent process and the yield of the printed products. Understanding the causes of condensation helps us to better control our production and improve print quality.
I. Occurrence of Condensation
 1. What is condensation?
  Condensation is the condensation of a gas or liquid when it is cold, such as water vapor turns into water when it is cold, and water turns into ice when it is cold. Therefore, the greater the temperature difference between the surface of the material and the ambient temperature, the higher the relative humidity in the air environment, the more likely it is to condensate.
  Humidity indicates the degree of dryness and wetness of the air, that is, the physical quantity of water vapor contained in the air. The less water vapor there is in a certain temperature and volume, the drier the air, and the more water vapor, the more humid the air. The degree of wetness and dryness of the air is called "humidity".
 2. Condensation of printed materials (aluminized film).
 The aluminized film is a bright metallic film formed by evaporating high-purity aluminum wire into a gaseous state at a high temperature (1100~1200°C) through the vacuum aluminization process, and then the gaseous aluminum molecules precipitate onto the surface of the plastic film when the plastic film passes through the vacuum evaporation chamber. Aluminized film is one of the indispensable materials in the flexible packaging industry, whether as a composite material or a printing material, the condensation phenomenon has a great impact on the processing of the above two common processes.
  Aluminum is a good conductor of heat, its thermal conductivity is three times greater than iron, and aluminum can be used to make various heat exchangers and heat dissipation materials in industry. Therefore, when the surface temperature of the material is lower than the ambient temperature, the water vapor around the material will condense and adsorb on the surface of the aluminum layer. Such a temperature difference and the high relative humidity in the air during the rainy season make it easy for the aluminum layer on the surface of the aluminized film to form a "water mist" that is invisible to the naked eye, which is the condensation of the material.
  3. The condensation phenomenon of gravure printing plate roller and ink plate
  The structure of the gravure printing plate roller is composed of a basic steel roller, a nickel layer, a copper layer and a chromium layer, and the manufacturing process is to plate other plating layers to the surface of the roller by electroplating on the basis of the steel roller. In short, the gravure printing roller is made of metal from the inner layer to the outer layer, and all kinds of metal materials are also easy to form a temperature difference with the ambient temperature.
  The ink disc is one of the indispensable devices in gravure printing, which is loaded with prepared printing ink and dilution solvent.
  The plate roller is soaked in the ink of the ink tray, and in the high temperature environment in summer, as the solvent volatilization speed in the ink disc accelerates, the solvent volatilization will take away the heat of the ink on the surface of the plate roller and the ink tray, so that the plate roller and the ink will produce a temperature difference with the ambient temperature at the same time. When the relative humidity in the air is high and there is a lot of water vapor around, the condensed water will be adsorbed on the plate roller to form a "water mist", and stay in the ink, resulting in excessive ink water content. This also disrupts the volatile balance of the dilution solvent, and the resin expands and precipitates, resulting in printing adhesion and paste, which directly affects the drying speed and the quality of the printed matter.
 II. Existing Solutions
 At present, some medium and large enterprises have made a closed space for each printing unit and installed a constant temperature dehumidification device (power consumption is about 10~15kW) to ensure that the overall production environment can achieve constant temperature and humidity controllable. However, some small and micro gravure printing companies have no way to do this due to various reasons.
  In the case of printed materials, the solution for medium to large enterprises is to store the aluminized film material in a warehouse with refrigeration and dehumidification equipment installed. However, small batch printing or enterprises that do not have the above-mentioned storage conditions cannot do so, which has a greater impact and directly affects the printing effect.
  1. Advantages of existing solutions
  The advantage of the existing solution is that the gravure printing machine is always in a relatively stable and controllable temperature working environment during the production process, regardless of how many groups are printing in the middle from unwinding to rewinding. It has strong adaptability to the production environment and is not affected by temperature and humidity throughout the year. All kinds of printing materials such as films, aluminized films, papers, etc., as well as various inks and solvents, will not be affected by environmental changes.
  2. Disadvantages of existing solutions
  The disadvantage of the existing solution is that the enclosed production space needs to be larger, and the enclosed space cost is higher in the whole group of printing equipment workshops. The purchase cost of dehumidification equipment is high, ranging from hundreds of thousands to two or three hundred thousand. Violating the law of conservation of energy, printing equipment is thermal energy drying, the main principle of dehumidification equipment is through the principle of compressor refrigeration, in the case of relatively low temperature can play the effect of dehumidification, not only to ensure the working temperature of the printing and drying mechanism, but also to maintain a constant temperature state for the production workshop, the contradictory result is to lead to an increase in electrical energy consumption, thereby affecting the production cost. This is also the reason why small and micro enterprises shy away from large-scale cooling and dehumidification equipment.
  III. Idea of Economic Solutions
  1. Moisture solutions for printed materials (omitted, please click "Read the original" for more content)
  2. Solution to the condensation phenomenon of printing plate roller and ink disc (omitted, please click "Read the original article" for more content)
 IV. Conclusion
  To sum up, the proposed scheme is one of the methods to solve the problem of water mist formed by the high temperature and humidity of metal film materials, moisture-prone film materials and plate roller ink discs in the rainy season. Compared with the old treatment method, the ideas proposed in this paper have the advantages of a wider range of applicable enterprises, lower cost, and lower relative energy consumption, which is more in line with the national policy of energy conservation and emission reduction.