According to analysis, the crust formed during normal ink storage and the crust that appears during the printing process often bring many problems to the operators of printing companies and printing machines, such as the reduction of printing costs and the decline of the quality of printed products. . The ability to effectively control the crusting of ink before printing and during the printing process is of great significance to printing companies.
The so-called ink crust refers to: due to normal temperature oxidation, infiltration, evaporation, evaporation and other drying, resulting in packaging printing ink in the storage or printing process, the surface layer printing and air contact, vegetable oil oxidation or organic solvent volatilization, resulting in the ink System polymerization and other effects formed by the gel. When the concentration of printing ink is increased to a certain value, the surface is covered with a layer of molecules. Even if additional solvent or grease is used to reduce the concentration of ink, the surface that has been skinned (gel) may not be able to Accommodate more molecules.
When the ink skinning phenomenon is serious, it will have a great influence on the stability of the printing cost. According to calculations, the lighter wastes 1%, and the weight is nearly 4%. This tangible consumption has added a heavy economic burden to packaging and printing companies. Secondly, the impact on the quality of printed products cannot be ignored. When the ink is crusted in the printing process, the ink skin will be distributed to various parts of the ink transport under the effect of rolling, which will have a great influence on the normal ink flow. At the same time, when the ink skin sticks to the printing roller, it will Makes a sudden change in the density of the plate; when the ink is transferred to the printing plate and the blanket, it will cause a ring-shaped mark on the print; when the ink skin adheres to the water roller, it will make the water transfer. Abnormally, dirt appears; the ink stick may also adhere directly to the surface of the paper.
From the above we can see that it is necessary to prevent and handle the crusting of ink. So how does the crust phenomenon of ink appear?
As mentioned above, the phenomenon of ink skinning is an oxidative conjunctiva phenomenon of the binder in an ink. The mechanism of the conjunctiva is the same as the mechanism of the ink drying. It is also affected by factors such as temperature, humidity, oxygen in the air, and desiccant content in the ink. Simply put, the skinning phenomenon of the ink is actually an oxidized conjunctiva of the ink we do not want to see (because we do not want the conjunctiva to appear conjunctiva).
There are many factors that can cause ink crusts, but in the main there are several categories: the dry oil content in the ink is too high; due to temperature; due to prolonged contact with ink and air. Below we will do some analysis separately.
1. The dry oil content in the ink is too high
Such mistakes may occur during the manufacture of the ink or during the printing process. Add desiccant must be added in conjunction with printing conditions and ambient temperature, otherwise the ink will dry (skin) when you do not want to dry. As for the use of desiccants, it is not repeated here.
2. Due to temperature
The crust of ink caused by temperature is mainly caused by high temperature. When the temperature is too high, the activity of unsaturated molecules in the ink increases, especially the part of the surface exposed to air is more likely to be conjunctivally oxidized under the action of oxygen. The high temperatures mentioned here have the following aspects:
a) The ambient temperature is too high. According to our experience, the crusting phenomenon of the ink in the summer is generally much more pronounced than in the winter. If there is no air conditioning in the workshop, it will be more obvious. It is necessary to reasonably control the temperature of the working environment. In general, it is an ideal temperature to control the temperature of the workshop at about 20°C, that is, to ensure the good flowability and transfer performance of the ink, and to control the crust of the ink. A relatively low degree.
b) When the temperature on the machine (such as the ink roller) is too high, the ink will also cause skinning during the printing process. When the contact pressure between the ink roller is too large, the temperature rise is more obvious, and at this time, the ink is likely to appear on the ink fountain and the ink roller.
The so-called ink crust refers to: due to normal temperature oxidation, infiltration, evaporation, evaporation and other drying, resulting in packaging printing ink in the storage or printing process, the surface layer printing and air contact, vegetable oil oxidation or organic solvent volatilization, resulting in the ink System polymerization and other effects formed by the gel. When the concentration of printing ink is increased to a certain value, the surface is covered with a layer of molecules. Even if additional solvent or grease is used to reduce the concentration of ink, the surface that has been skinned (gel) may not be able to Accommodate more molecules.
When the ink skinning phenomenon is serious, it will have a great influence on the stability of the printing cost. According to calculations, the lighter wastes 1%, and the weight is nearly 4%. This tangible consumption has added a heavy economic burden to packaging and printing companies. Secondly, the impact on the quality of printed products cannot be ignored. When the ink is crusted in the printing process, the ink skin will be distributed to various parts of the ink transport under the effect of rolling, which will have a great influence on the normal ink flow. At the same time, when the ink skin sticks to the printing roller, it will Makes a sudden change in the density of the plate; when the ink is transferred to the printing plate and the blanket, it will cause a ring-shaped mark on the print; when the ink skin adheres to the water roller, it will make the water transfer. Abnormally, dirt appears; the ink stick may also adhere directly to the surface of the paper.
From the above we can see that it is necessary to prevent and handle the crusting of ink. So how does the crust phenomenon of ink appear?
As mentioned above, the phenomenon of ink skinning is an oxidative conjunctiva phenomenon of the binder in an ink. The mechanism of the conjunctiva is the same as the mechanism of the ink drying. It is also affected by factors such as temperature, humidity, oxygen in the air, and desiccant content in the ink. Simply put, the skinning phenomenon of the ink is actually an oxidized conjunctiva of the ink we do not want to see (because we do not want the conjunctiva to appear conjunctiva).
There are many factors that can cause ink crusts, but in the main there are several categories: the dry oil content in the ink is too high; due to temperature; due to prolonged contact with ink and air. Below we will do some analysis separately.
1. The dry oil content in the ink is too high
Such mistakes may occur during the manufacture of the ink or during the printing process. Add desiccant must be added in conjunction with printing conditions and ambient temperature, otherwise the ink will dry (skin) when you do not want to dry. As for the use of desiccants, it is not repeated here.
2. Due to temperature
The crust of ink caused by temperature is mainly caused by high temperature. When the temperature is too high, the activity of unsaturated molecules in the ink increases, especially the part of the surface exposed to air is more likely to be conjunctivally oxidized under the action of oxygen. The high temperatures mentioned here have the following aspects:
a) The ambient temperature is too high. According to our experience, the crusting phenomenon of the ink in the summer is generally much more pronounced than in the winter. If there is no air conditioning in the workshop, it will be more obvious. It is necessary to reasonably control the temperature of the working environment. In general, it is an ideal temperature to control the temperature of the workshop at about 20°C, that is, to ensure the good flowability and transfer performance of the ink, and to control the crust of the ink. A relatively low degree.
b) When the temperature on the machine (such as the ink roller) is too high, the ink will also cause skinning during the printing process. When the contact pressure between the ink roller is too large, the temperature rise is more obvious, and at this time, the ink is likely to appear on the ink fountain and the ink roller.
Furniture And Cabinet Fittings
Cabinet Lift Support,Sliding Door Pulley,Cabinet Door Lift Support,Furniture And Cabinet Fittings
Wenzhou Zhaoxia Hardware Co.,Ltd , https://www.zhaoxiahardware.com