Printing static control

In the printing process, static electricity brings many hazards. It not only hurts the operators, but also makes qualified prints completely messy. To prevent static electricity from time to time, it is best to start with it and destroy it before it harms production.

In the areas where static electricity occurs, in addition to the parts in which the paper and the roller are in contact, such as paper guide rollers, nip rollers, floating rollers, printing heads, delivery piles, roll-up devices, overprint rollers, etc., static electricity also appears in other parts. Some occasions, such as plastic film bases, printing machinery and coating production lines. Under these circumstances, if the static electricity is not controlled effectively, the accumulation of dust will reduce the number of qualified products and subject the operator to electric shock. In addition, if solvent-type inks are used, fire and explosion may also occur.

UV inks are particularly susceptible to electrostatic phenomena, causing some of the particles in the ink to adhere to blankets and other machine parts. It is likely to cause secondary contamination of the printed sheets, some white spots (deinking failures) or ring-shaped white spots.

Static electricity makes the cleaning roller abnormally difficult, and if the roller is not cleaned cleanly, the quality of the product is also reduced, and the number of shutdowns and time are increased. Eliminating or reducing static electricity to less than 500 volts is very important for cleaning the drum, which can greatly improve work efficiency. Otherwise, the drum itself may absorb more dust than before cleaning, making production impossible.

Efficient control of static electricity is to eliminate static electricity or to control it effectively. It has been a topic of debate for printing companies. Although some products that control static electricity use the name “static electricity,” these products do not actually remove static electricity. It is almost impossible to completely eliminate static electricity, because static electricity will be present wherever there is contact, and the contact between various parts and materials inevitably occurs in the printing process, and static electricity cannot be avoided. produce.

In theory, we can reduce static electricity to a certain extent so that it is completely unaffected by the process of production. Although this is not realistic and unnecessary, we can carry out the charge on the contact surface at a specific stage. Effective control, such as when the charged material passes through the ionizer, the static electricity will be reduced, and when the friction occurs with other parts, the static electricity will reappear.

In the packaging and printing industry, tinsel (gold paper) is the most commonly used method for controlling static electricity, and it is also the most attractive method. The key is the cost of this method. Cheaper. Although these static removal methods work well, it is difficult to say that they are the most appropriate method. For example, tinsel products often scratch the film base.

Tinsel controls the speed of static electricity very quickly, but if it is more than 3,000 volts of static electricity, other methods have to be chosen. Most static-related transfer and printing problems can be solved by the tried and tested method of eliminating static electricity.

In the fast-rotating web production line, the AC ion rod is a relatively common method of controlling static electricity, and the effect is very good, but the control range is extremely limited. It is recommended to install a few inches more on the surface of the drum in order to optimize the control performance.

The method of recommending more static electricity to the user is the AC electrostatic neutralizer, which has good effects, low cost, and ease of use. In addition, it has the advantages of durability and easy maintenance.

In addition, the DC destaticizer is an adjustable device that can generate corresponding positive ions or negative ions according to the different charges generated, and neutralize the static electricity. This is also a popular method of controlling static electricity. The DC stick neutralizes the electrostatic energy in a wide range and is suitable for the winder, which can be used as an alternative to the expensive AC ion blower.

In the packaging and printing market, the next step in controlling static electricity may have to focus on monitoring technology. The recently introduced Model 177 fieldmeter/monitoring system (developed by Monroe Electronics) is very useful for solvent-based inks and other explosive environments where the system can monitor and control four areas of the press cylinder at the same time. After controlling the electrostatic device, monitor the working efficiency of the ionizer.

Ion System also developed AC intelligent electrostatic neutralization equipment with built-in diagnostics and performance monitor. It consists of a solid, high-voltage energy supply, built-in monitoring circuit, computer interface module, and electrostatic neutralization rod. To manage each neutralizer and alert the operator of possible problems through a computer.

With this trend, Simco recently introduced Blue Bar/M167, a supervised energy supply that monitors operations and warns operators of any problems with the control rods, such as bending or misconduct.

Many of the design structures of the positioning printing press have become a static electricity accumulation place. If you want to control the static electricity in each place, you will have to add a lot of equipment. This excessive control will cause unnecessary burden on the enterprise, usually With proper equipment, static electricity can be controlled within an acceptable threshold.

Where to place the static control device is just as important as choosing which method to control static electricity. Usually, a method called “minimum requirement” is adopted. The device that controls static electricity is directly positioned in the process and often causes problems due to static electricity. local. And those static electricity between 50 volts and 100 volts will not have any impact on production at all, so there is no need to consider it.

Some tips for controlling static electricity Check the ground wire - If the operator is often hit by static electricity, the first thing that should be thought of is checking the proper connection of the ground wire.

Increased humidity - After increasing the relative humidity (RH), static electricity is reduced a lot, because humidity can increase the electrical conductivity of some insulating materials. The relative humidity in the workshop should be at least between 55% and 60%. One negative effect of increasing the humidity is that the surface of the material is too moist and the working environment is not comfortable.

Consider many factors - the causes of static electricity are many, such as speed, tension, pressure and relative humidity. Checking the ground may help, but keep in mind that some materials may not have the ability to ground; reducing the speed at which the machine operates reduces the friction between materials may help, but it reduces production. Therefore, we must consider the issue in many aspects and try to balance the different factors as much as possible.

The accuracy of the control is measured—Measurement of control statics can increase the operational capacity of the control equipment and help determine whether new equipment needs to be replaced or whether it is necessary to change the location of the installed equipment.