Corrugated cartons flexographic outlets influencing factors analysis of two

Printing plate

â–  Film selection

For fine dot printing, films need to use better quality products. For demanding dot-printing, domestic film is hard to achieve the desired effect, and only high-quality foreign films can be selected.

â–  Selection of media

The resin plate has different hardness, and the dot diffusion is mainly caused by the expansion of the dots on the plate under the pressure. In order to reduce the number of dots, the use of a harder plate is a solution, but in actual use, the deformation of the plate is too small and the bottom of the bowl is partially exposed. In order to eliminate this phenomenon, it is necessary to add a platen roller. The pressure, but at the same time it will increase the deformation of the printing plate. Therefore, the choice of media needs careful consideration. At present, there is a liquid version, its greatest advantage is that it can make the top of the printing plate dot to have a higher hardness (the hardness can be selected at 36?2), and the matrix part can be chosen to have a lower hardness, and the author's company has tried it. The effect is obvious.

â–  Choice of outlets

There are many kinds of dot shapes. The dot used on the plate with a hardness of about 36 degrees is based on the author's own experience that the circle effect is better. The square shape and the diamond shape are obviously deformed in use, and dot dot diffusion or dot adhesion is prone to occur. The phenomenon. Occasionally, the customer's designer does not consider the actual condition of the corrugated box, a series of problems may arise.

â–  Carton design

Due to the current shortage of carton design professionals, many corrugated box printing designs are provided by customers, and customers' design drafts are designed by advertising companies or are designed directly with offset printing. Therefore, carton suppliers are required to produce. This will certainly not occur. Less problem. For example, there are too many color requirements, the number of dot lines is too high, and the highlight part is too high (the dots below 3% are not guaranteed and may be lost). Vector and bitmap relations are difficult to handle in the production of corrugated boxes. Therefore, the carton design requires that carton suppliers have professional designers or need professional plate makers to complete.

equipment

â–  Anilox roller

The anilox roller is the heart of the printing machine. At present, there are mainly two kinds of metal anilox roller and ceramic anilox roller. From the perspective of using effect, there is not much difference between the metal anilox roller and the ceramic anilox roller. The main difference between them is that the number of ceramic anilox rollers with the same number of lines is greater than that of metal anilox rollers; ceramic anilox rollers are relatively prone to network blockage; ceramic anilox rollers have better durability.

In general, when the number of lines of the anilox roller is at least 5 times the number of lines required for printing, no stencil phenomenon occurs. The anilox roller needs regular cleaning to ensure its ink loading. In the dot printing, the ink volume control should be as small as possible to ensure the dot clear, and the ink volume is opposite.

â–  Scraper and rubber roller

The difference between a doctor blade and a rubber roller is that when the doctor blade is used, the amount of ink carried by the anilox roller is independent of the speed of the printer. When using a rubber roller, the ink loading of the anilox roller increases as the speed of the printing press increases. It is best to use a squeegee in dot printing to ensure consistent ink levels. When using a rubber roller, it is important to control the speed of the vehicle, and it is very important to maintain the consistency of the ink when it is repeated.

â– Printing machine

Some of the corrugated box printers have the function of infrared drying and blow drying, which can accelerate the drying of ink and avoid the proliferation of dots due to insufficient drying of the underlying ink.

â– R/BAK pad

The role of the R/BAK pad is to reduce the deformation of the plate by suitable deformation in the corrugated box printing. In actual production, the dot diffusion at the peak can be reduced.

Polishing

At present, customers have more and more requirements for corrugated boxes, such as ink abrasion resistance and waterproofness. In order to meet the requirements of customers, many corrugated cartons have been increased in the production of this process. There are many types of varnishes and their uses are different. When using varnishes, it is best to choose products that have poor re-solubility with inks. If they do not achieve the desired results, they can only choose the method of glazing after printing first.

operator

The operating level of the printing press operator is a key factor in the production. It is crucial to master the gap between the rubber roller (scraper), the anilox roller, the printing roller, and the embossing roller in actual production. The flexographic plate hardness is not high and it is easily deformed, so the clearance between the anilox roller, the printing roller, and the embossing roller should be just right.

Rubber roller (squeegee) and anilox roller gap can control the amount of ink, too much ink will be fuzzy dot network, ink is too small, the color is not full; anilox roller and printing roller gap can control plate and anilox roller The pressure, if the gap is too large, the printing plate can not evenly ink, the gap is too small will cause deformation of the upper plate, resulting in ink between the dots, there will be dot adhesion after printing; the gap between the printing roller and the embossing roller is It is to control the pressure of the printing plate and the corrugated board. Too much pressure will deform the lower plate of the printing plate. The dots will spread badly on the peak, and the corrugation marks will be obvious. The pressure will be too small to make the plate and the cardboard unable to fully contact, and there will be no ink in some positions.

In addition, the surface of the printing roller and the embossing roller should be clean and free of ink and other dirty things. The feed roller gap in the feed section must be just right, neither can crush the corrugated board, but must also be able to accurately feed the corrugated board into the machine.

In the long-term production, there will be remnants of the ink on the plate, which will cause the dot to be blurred, and the plate needs to be cleaned in time. During the production, we must also pay attention to maintaining the viscosity of the ink and the consistency of the PH value. If necessary, add water or additives. Finally, in order to avoid abnormalities, frequent convulsions are also very important.

---Carton Technology