Haida: Analysis of Common Problems in the National Standard of Carton Paper and Carton Printing

Haida: Analysis of Common Problems in the National Standard of Carton Paper and Carton Printing

The base papers used by cartons manufacturing enterprises in China can be divided into imported base papers and domestic base papers if they are classified according to their origins; if they are divided according to the types of base papers, they can be divided into kraft paperboards ( also known as kraft linerboards in China ) . Corrugated paper, whiteboard paper for high-end packaging printing, noodle kraft paper, coated kraft paperboard, etc. Due to the rapid development of China's carton industry, the demand for base paper has been increasing year by year, especially for coated kraft paperboard, because it has the advantages of both kraft linerboard and coated whiteboard, and also has the strength of kraft linerboard and whiteboard paper. The adaptability, so the import volume is significantly increased. In recent years, although the overall quality of the domestic base paper has been greatly improved, there is still a gap compared to the quality of the base paper abroad, and even if individual paper mills can reach the same level in foreign countries, but in some low-weight, high-strength kraft paper As for the production of corrugated paper, due to the limited production capacity, it is still unable to meet the demand. Most of them are still dependent on imports. For imported raw paper, the inspection and quarantine authorities of China have specific provisions: In accordance with the provisions of the "Commercial Inspection Law", commodities listed on the category list must be inspected by the inspection and quarantine agency or its designated inspection department, and must not be sold or used without inspection. Most of the paper used in cartons imported by China are statutory products that must be inspected. The current inspection and quarantine department

When testing these papers, the following inspection criteria are followed:

1. Mandatory standards of laws and regulations or other inspection standards that must be implemented;
2. If there are no mandatory standards or other mandatory inspection standards for laws and regulations, they may be inspected according to the standards agreed in the contract between the two parties. ( If the mandatory standards of laws and regulations are lower than the standards stipulated in the contract, they shall be executed according to the standards stipulated in the contract ) ;
3. None of the above two points can be tested according to the standards of the producing countries, relevant international standards or the standards specified by the national inspection and quarantine agencies. For those who do not have a suitable test standard, select the approved internal method standard.
Here we need to specifically address the above-mentioned second point. During our actual inspection, we found that most domestic users do not have enough agreement on the quality terms of the imported base paper in the trade contract, and even there is no agreement. They often only recognize the brand. And origin, while ignoring the quality of the product itself. In the first half of this year, there were several batches of imported paper that were inspected by our inspection and quarantine departments and found to be of quality problems. However, because the customer did not prearrange the quality requirements and inspection standards of the goods received in the contract, the inspection and quarantine department issued a non-conformity certificate. Difficult to come, to the customer's own claims and return shipments brought troubles, therefore, we call for companies importing base paper should be agreed in the contract quality terms in order to protect their own income.

Dirty, stenciled or partially illlustrated quality issues in layout graphics

1 、Quality failure caused by bad parts related to machine stamping

When the plate cylinder head, the platen roller head, the drive shaft, the gear, and the important parts associated with the embossing are worn and loose, the plate roller or the embossing roller may be beaten during the embossing process. Sliding phenomenon, due to the pressure instability, resulting in improper contact between the printing plate surface and the cardboard, resulting in the cardboard printing surface appears paste plate or local graphic image unclear. Through careful observation and analysis, the exact location of the fault was identified, and appropriate measures were taken to deal with it. The worn and loose parts were repaired to eliminate the fault phenomenon.

2. Quality failure caused by bad ink roller

When the ink roller head is loosened and the roller roller body is bent, deformed or the surface is damaged, it will cause the layout to be dirty, the paste plate, or the local graphic is not clear. Should find out the reasons, take appropriate measures to deal with, so that the ink roller and the printing plate to maintain uniform and appropriate contact conditions, replace the damaged ink roller, in order to eliminate the phenomenon of failure.

3 , quality failure caused by improper adjustment of pressure roller

If the position of the pressure roller is too high or too low, so that the contact with the corrugated cardboard is too tight or too loose, there will be dirty prints, stencils, or local image imprints. Adjust the pressure roller to a suitable position so that the pressure The gap between the roller and the roller is adapted to the thickness of the board to ensure the position of the printed board and to avoid the occurrence of this malfunction.

4. Quality failure caused by incorrect color sequence

If the layout of the fuller layout is printed in the first color group, when the corrugated cardboard enters the printing process of the next color group, since the printing image of the first color group of the cardboard has a large amount of ink and the drying speed is slow, it is extremely easy. Transfer the blots to make the layout dirty. In order to prevent this problem from occurring, it is advisable to arrange small-size layouts in the first color group, and to arrange large-size layouts in the subsequent color group to avoid imprint migration caused by dirty printing.

5 , the quality of the plate caused by the uneven quality of failure

When the thickness of the rubber plate is not uniform, the height of the plate layout will be different. High layout where it is easy to paste version, low layout places prone to dwell on failure, resulting in imprinting is not clear, in order to avoid this undesirable situation, the plate can be sporadic manner, the plate is made of several small pieces ( means that conserve material without flexographic process printing plate core), should be made with a plate, respectively, such that the difference in thickness is relatively small. If the already prepared rubber plate has a poor thickness, it can be compensated by a multi-adhesive layer on the back of the partially thin plate, so that the entire plate can maintain a substantially uniform thickness, ensuring the printing pressure and the evenness of the printing surface of the plate.

6 , the quality of corrugated board thickness caused by the quality of failure

If the surface of the formed corrugated cardboard has a sabotage mark on the surface, the paper surface of the recessed area will also have unclear quality defects. If this is used to increase the printing pressure and make up for it, the text and the line layout will easily appear lumpy. Quality issues. In order to prevent the layout from becoming lumpy, corrugated cardboard should be handled lightly, lightly, and lightly (in order to control the stacking height ) during stacking and handling, and should not be transported by unfavorable production practices such as throwing, squeezing, and pressing.

Inaccurate or unstable quality problems in layout printing

1 、The printing position caused by the curling of corrugated board is not allowed

If the corrugated cardboard has a curling defect, slipping occurs easily during the positioning and feeding of the paper board, and even the rules on the machine do not touch the paper edge, causing the printing position of the paper board to be inaccurate or unstable. When the warped corrugated cardboard is printed, the relatively flat paper edge is used as the regular paper edge positioned when feeding. The most important is the control of the source of quality. Through the reasonable control of the single-sided machine operation process, the speed and preheating temperature of the machine, the moisture content of the base paper and the preheating area are in a relatively coordinated state ; when comparing the paper, attention is paid to comparing the moisture content. Closed boxboard paper and corrugated paper are used for supporting the synthetic type, so that the corrugated paperboard produced has a relatively flatness and can effectively ensure the accurate printing position.
2. Inaccurate printing position due to improper operation process

If the position of the plate is improper, it can easily cause the position of the platen to be inaccurate. Because corrugated paperboards with warp defects have just entered the plate rollers, if there is a slight amount of slipping, the tip of the paperboard will show a significant deflection. Therefore, the corrugated paperboard has a colored layout, and it should start as far as possible toward the rollers. The location of the paper is positioned, and the corresponding measures are determined to be repaired accordingly. After the loosening of the parts is eliminated, the printing position of the corrugated cardboard can be ensured accurately.

3 , positioning is not allowed due to poor machine

When the machine's chain, rules and other parts have loose phenomenon, it is also easy to cause layout printing position is not accurate, this should take appropriate measures to repair, eliminate the loose parts phenomenon, in order to ensure the accuracy of corrugated board printing position.

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