1、 Influence of ink emulsification on Printing   Ink Over Emulsification And Its Preventive Measures

      If the ink emulsification is just right, it indicates that the water and ink are in a relatively balanced state, creating good printing conditions for offset printing. Ink Over Emulsification And Its Preventive Measures

      The graphic ink can realize the transfer of ink, so as to obtain the printing effect of bright and clean mesh points, clear images, rich layers, bright colors and saturation, Ink Over Emulsification And Its Preventive Measures

      ensure the accuracy of overprint and promote the drying of printed products, At the same time, ensure that the blank part of the non printing area is clean and tidy. Ink Over Emulsification And Its Preventive Measures

      Therefore, whether we can correctly grasp and control the emulsification of ink is the key to ensure the balanced and stable printing quality of water and ink. If the ink is not mastered properly, resulting in excessive emulsification of ink, Ink Over Emulsification And Its Preventive Measures

      it will inevitably lead to the imbalance of ink, which will have a negative impact on the printing quality. In practice, if the ink is not mastered properly, it is easy to have excessive ink emulsification, which is very harmful to the printing quality.Ink Over Emulsification And Its Preventive Measures

        Ink over emulsification means that there are too many small droplets scattered in the ink, exceeding a certain proportion, and the properties of the ink change immediately, such as color fading, color saturation decreasing, viscosity decreasing, adhesion weakening, etc., resulting in the instability of process and print quality. Ink Over Emulsification And Its Preventive Measures

     For example: the gray balance is broken, the color is not restored, the printing color is gray and the level is not clear; The ink transmissibility deteriorates, the ink color changes from big to small, and the ink color before and after the product varies greatly; It is prone to process faults such as floating dirt and plate pasting, Ink Over Emulsification And Its Preventive Measures

       and the drying performance of imprinting is greatly slowed down, which is easy to cause sticking dirt on the back. Therefore, it is necessary to control the printing quality and prevent excessive ink emulsification as far as possible.Ink Over Emulsification And Its Preventive Measures

2、 Causes and prevention of ink over emulsification   Ink Over Emulsification And Its Preventive Measures

     There are many factors causing excessive emulsification of ink, mainly including paper, fountain solution, ink, diluent and desiccant. Therefore, to avoid excessive emulsification of ink, we should apply the medicine to the case according to different influencing factors and take precautions.Ink Over Emulsification And Its Preventive Measures

1. Paper factor

      Since the surface of paper, such as some offset paper, coated paper and whiteboard, contains more or less some surfactant in the rubber, coating or other fillers on its surface, they have a certain water solubility. Ink Over Emulsification And Its Preventive Measures

       If they are not firmly combined with the paper, they will be soaked in the fountain solution and extruded and stripped by the blanket during the printing process, These surfactants fall off and are transferred to the ink roller and bucket through the printing plate, and integrate with the ink, Ink Over Emulsification And Its Preventive Measures

       which greatly reduces the viscosity of the ink, increases the water absorption, affects the water resistance, and causes excessive emulsification of the ink.Ink Over Emulsification And Its Preventive Measures

        The more moisture in the layout, the more dissolved fillers and the more serious emulsification; The paper with poor sizing, loose paper, and more serious powder and hair loss is more likely to be over emulsified.Ink Over Emulsification And Its Preventive Measures

Preventive measures: Ink Over Emulsification And Its Preventive Measures

   ① use paper with good quality to fundamentally eliminate excessive emulsification of ink caused by paper; ② Wash the rubber and printing plate frequently, and remove the falling paper powder and paper wool in time;Ink Over Emulsification And Its Preventive Measures

       ③ Add a small amount of additives to the ink, reduce the moisture of the layout and reduce the pressure of the water roller, so as to reduce the paper de powder and hair.Ink Over Emulsification And Its Preventive Measures

2. Fountain solution factors

       The dispersion of fountain solution is one of the conditions causing ink emulsification. Under the extrusion of mechanical force, the water film on the surface of the printing plate forms small droplets to disperse and penetrate into the ink, Ink Over Emulsification And Its Preventive Measures

      causing ink emulsification. Therefore, the amount of fountain solution is too large, the water film of the printing plate is too thick, Ink Over Emulsification And Its Preventive Measures

       the water distributed along the ink roller increases, and it is squeezed by the roller and the ink roller, It promotes the acceleration and over emulsification of ink emulsification. Ink Over Emulsification And Its Preventive Measures

      The greater the amount of water, the thicker the water film, the smaller the pH value, and the more serious the over emulsification.Ink Over Emulsification And Its Preventive Measures

Preventive measures: 

       ① control the amount of fountain solution and reduce the amount of ink and water while ensuring that the printing plate is not dirty and the imprint meets the quality requirements of level, density and color; Ink Over Emulsification And Its Preventive Measures

       ② Control the proportion of fountain solution. The pH value should not be too small. It is best to use alcohol fountain solution as much as possible.Ink Over Emulsification And Its Preventive Measures

3. Ink factor

      Ink viscosity is the main factor of emulsification. Regardless of the viscosity, it can produce different degrees of emulsification. Ink viscosity is large, its molecular cohesion is large, water resistance is strong, and the emulsification value is small; Ink Over Emulsification And Its Preventive Measures

       On the contrary, if the ink viscosity is small, the fluidity is strong, the cohesion between molecules is small,Ink Over Emulsification And Its Preventive Measures

        and the water resistance is poor, it is easy to emulsify. Generally, ink viscosity is inversely proportional to emulsification, while fluidity is directly proportional to emulsification.Ink Over Emulsification And Its Preventive Measures

       The different water repellent ability of pigment itself will also cause the change of ink emulsification value. For example, the water resistance of black ink and red ink is better than Qinglian and Malachite blue ink, and the emulsification value is also smaller.Ink Over Emulsification And Its Preventive Measures

      Preventive measures: ① select ink with good water resistance; ② For the ink that is easy to emulsify, add No. 0 ink blending oil appropriately to increase the viscosity of the ink, and try not to reduce the viscosity of the ink by adding No. 6 ink blending oil; ③ Replace with new ink.

4. Diluent and desiccant factors

       The commonly used diluents mainly include diluent, white oil, white ink, vitamin oil, etc. the diluent is an amphoteric oxide with strong moisture absorption and large emulsification value. The emulsification value of white oil is also large, which is very easy to cause ink emulsification.

        If these diluents are added to the ink, the ink emulsification must be accelerated; Driers such as white dry oil and red dry oil have large emulsification value. Ink Over Emulsification And Its Preventive Measures

      Adding an appropriate amount of driers can speed up the drying of ink, but if added too much, it will reduce the drying speed of ink and worsen the emulsification of ink.

      Preventive measures: add diluent or desiccant according to the specific situation. Do not add it blindly. Try to control it within a certain amount, generally about 2% – 3%, not more than 5%.Ink Over Emulsification And Its Preventive Measures

5. Over emulsification caused by other factors

        Other factors such as workshop temperature, humidity, vehicle speed and the pressure of water roller and ink roller will also have a certain impact on ink emulsification. Ink Over Emulsification And Its Preventive Measures

      For example, the higher the workshop temperature, the higher the surface temperature of the drum and ink roller, the thinner the ink, and the greater the fluidity, the smaller the viscosity and the weaker the water resistance. Ink Over Emulsification And Its Preventive Measures

      If the vehicle speed is high, the interaction force is large. These factors play a strong catalytic role in the excessive emulsification of the ink. The greater the workshop temperature, the easier the ink is to emulsify.

        Preventive measures: 

① the workshop shall be equipped with air conditioner as much as possible, and the workshop temperature shall be controlled between 20 ℃ – 26 ℃ and the humidity shall be controlled between 53% – 65%; Ink Over Emulsification And Its Preventive Measures

② Pay attention to adjust the pressure of water roller and ink roller to make it within an appropriate range to ensure smooth water and ink delivery; Ink Over Emulsification And Its Preventive Measures

③ During shutdown and idling, the water supply and ink supply shall be shut down to avoid large water and ink accelerating ink emulsification.Ink Over Emulsification And Its Preventive Measures

        There are many factors that affect the emulsification of ink, and many times, the causes of excessive emulsification of ink are often the joint action of several factors, such as small graphic area, Ink Over Emulsification And Its Preventive Measures

      low ink consumption, and emulsification easily occurs when the ink is in contact with water for a long time. Ink Over Emulsification And Its Preventive Measures

       If the water resistance of ink is poor and the water volume is too large, excessive emulsification of ink is more likely to occur. Therefore, we should analyze and eliminate the problem of ink emulsification one by one from many aspects. We must establish the idea of prevention in the first place and focus on prevention.Ink Over Emulsification And Its Preventive Measures

          In addition to controlling the quality of raw materials, we should also develop good working habits and standardize process operation, such as “three leveling” and “three diligence” to find and solve problems in time,.Ink Over Emulsification And Its Preventive Measures

      And pay attention to accumulate experience, grasp appropriate ink emulsification as far as possible, control the balance of water and ink, and print high-quality prints with clear dots, clear layers and bright colors.Ink Over Emulsification And Its Preventive Measures