How to deal with color printing carton production quality problems

Color printing corrugated paper box and color printing corrugated paper box It is a neutral packaging which has both sales function and transportation protection function. It is very popular with the consumer products manufacturing enterprises. So in recent years, the corrugated box manufacturers have developed rapidly, but the color printing Corrugated cartons and color-printed corrugated boxes; There are often quality problems in the production process. The following experiences and lessons have been accumulated for this type of problem and are shared here with your peers.

common problem
The ink of the product is sticky or sticky

Due to the different materials, paper structures, and production processes of whiteboard, coated paper, offset paper, and when the low temperature and high ink viscosity during the winter, whiteboard paper is often found on the surface layer or coating layer where the ink is sticky or sticky. The broken phenomenon seriously affects the appearance quality of the printed matter.

Solution

Wetting powder and alcohol can be added to the dampening solution (5% to 20% ratio) to reduce the tension on the edge of the ink application area, or according to different types of ink, use the appropriate varnish, detackifier or diluting agent Reduce the viscosity of the ink.

The control of the printing room and room temperature is generally controlled at 19°C to 28°C. It is advisable to heat the ink properly during winter, which is beneficial to improve the fluidity of the ink and reduce the viscosity of the ink.
Choose a white paper with a high degree of nap, and the printing pressure should not be too great.

Under the blanket can not be more than the liner, the pad can not be soft, the blanket used after a period of time using a cleaning agent to scrub clean.

Color printing ink drying slow


This phenomenon can easily cause the printed material to become sticky and cause some difficulties in post-processing. This problem can be controlled from the following three aspects.

Switch to a base paper with a slightly stronger ink absorption performance: for example, coated whiteboard paper is more absorbent than bleached white paper.

Use a quick-drying ink or add an appropriate amount of desiccant according to the characteristics of the ink, and reduce the amount of ink applied to the inked area.

Properly extend the interval between processing or spread the prints to dry.

Differences in shades of ink and differences in color appearance in the same batch of prints

Use the following methods to control and receive better results:

The inks needed for the same batch of products are best formulated at one time. The required ink and the diluent, detackifier, desiccant and other additives must be measured with an instrument when inks are dispensed. And random ink distribution can also cause differences in hue.

The absorption performance, whiteness, and thickness of the base paper (white paper) used in the same batch of product should be consistent. The base paper with a large thickness will cause the printing pressure to increase and cause the ink color to be heavy. The white color of the paper will also cause the ink shade and color. Changes in appearance.

The ink balance on the printing roller should be well controlled, and the empty car must be strictly controlled, because after each empty car, the ink color of the first dozen or more printed products is obviously deeper, if the frequency of empty cars is high, Ink products with different shades of ink will naturally have more.

For products that need to be overprinted many times, the previous ink should be allowed to dry before the subsequent overprint.

White paper wrinkles


When whiteboard paper is used to print color printing sheets, if the water content of the formed paper is not uniform, flounced edges, wavy edges, or excessive drying of the environment leads to the edge of the paper evaporating and more tight edges appear. After many times of printing and wetting, white paper will wrinkle during the printing process.
To solve the wrinkles that occur during the color printing of white paper, first control the entrance of the raw paper. Before the whiteboard paper is printed on the machine, it is best to place it in the offset printing room one to two weeks in advance so that the moisture content of the paper and the humidity of the printing shop are balanced. If the air humidity in the printing room is relatively dry, it is better to spray some water on the ground to adjust the humidity of the air to prevent the edges of the paper from evaporating and the wrinkles caused by tight edges are more likely to be generated. The other is to replace or remove uneven raw paper.

Quality problems appearing in the veneering process

Causes of decals on printed overlays include the thickness of the paper, the direction of the flow of the paper, the solids content of the adhesive, the amount of glue applied on the corrugation peak, the pressure after veneering, and the moisture content of the paperboard.

The problem of Lucy can be controlled through the following ways:

Appropriately increase the chromaticity of the color printing surface paper, and use the characteristics that the horizontal stretching after the absorption of the original paper is greater than the longitudinal stretching, the longitudinal filament flow of the color printing surface paper and the corrugated cross into a "+" shape cross-fit.

Improve the solid content of the adhesive, reduce the water content in the adhesive, and adjust the gap between the squeegee roller and the pressure roller of the laminating machine (or the laminating machine) to ensure good adhesion between the color printing surface paper and the corrugated cardboard. Under the circumstances, try to reduce the amount of sizing on the peak.

After the veneer is dried, the moisture content is controlled at 9±2%, so that the fibers of the color printing facial tissue are shrunk. This also reduces the appearance of dew.

Adhesive or corrugated collapsing

Paste adhesives are generally the most commonly used oxidized starch adhesives. If the oxidized starch adhesives are not oxidized enough during the formulation process, or if the starch is oxidized too deeply, the quality of the adhesive will be unstable and the adhesive will open. . In addition, if the sizing amount is adjusted too small, there will be too little glue on the corrugation peak. If you are using hand-rubber for veneering, the lack of screed on each layer of linoleum or in-line paper will also result in unscrewing.

Laminating on the laminating machine; or hand-laminating the veneer, if the gluing amount is too large, it will easily cause the laminating clay to be too soft after being glued, and the lamination will collapse after laminating with the laminating paper. . Excessively sizing the glue not only wastes glue but also makes it difficult to dry the product after veneering. Therefore, the amount of sizing should be strictly controlled.

Color printing products fade during post-processing and loading and unloading

From the surface phenomenon, the color shift is mainly due to the mutual friction of the products in the post-processing and handling process. In fact, this problem is closely related to the ink preparation method. In the production process of color printing products, we often find that ink The viscosity is too large, causing ink roller uneven ink and prints sticky hair sticky ink. In order to solve this problem, detackifiers are often added to the ink. If a debonding agent is used uniformly for inks with different characteristics, then the phenomenon of discoloration will be very serious. Because the characteristics of different types of inks are different, Shanghai Ink Factory's Type 05 and Type 01 resin inks, for example, use improper detackifiers for ink reconstitution, which can cause crystallization of the ink (powder-like characteristics of the inks printed on the product) and cause the product to discolor. Type 05 light quick-drying resin ink can only add 0592-type detackifier, and the amount of addition and control should be controlled within 3%, while the 01-type resin ink can be used 3% of red oil and 6# varnish to Adjust its viscosity, under normal circumstances do not add detackifier, otherwise it will also cause color printing products fade.

In addition to the deployment of ink should be noted that in the process of post-processing and handling products, we must try to control the products and products, products and equipment, products and tools caused by dry friction between the fade, because the ink is not dried out In the case of poor dry friction, the new renminbi will fade with rough paper.

If the product is discolored, the method of remedy is to cover the surface of the print with a film or add a bright light to solve the problem of color removal.




Source: Qingdao Runhai Packaging Materials Co., Ltd.

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