Most popular carton quality from the perspective o

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From the perspective of ink printing, carton quality

release date: Source: China paper industry

as we all know, the key factors affecting product quality are equipment, raw materials, personnel and environment. The same is true of carton packaging industry. In order to build high-quality brands, many enterprises have spared no expense, updated equipment, made great technological progress, strictly controlled the entry of base paper into the factory, sincerely recruited talents from all over the world, and improved the working environment. These are commendable, but they will also benefit from being good at research, creativity, and being good at being intentional people. Here is a brief description of the experience of improving the quality of cartons from the perspective of ink printing

first, ensure the clarity of printing

first, the printing plate should be made of wear-resistant, moderately elastic and high-quality materials. The thickness of the plate of the same plate should be consistent. The thickness of the resin plate should not be less than 4mm, and the rubber plate should be 6-7mm. Whether it is made with negative film or hand knife carving, the layout must be neat, the handwriting pattern, and the line depth should not be less than 3mm. The arrangement of text patterns should not be overcrowded, the arc should be smooth, the thickness should be uniform, and the straight line should be straight and smooth. When printing, the ink should be properly diluted. The ink layer of the inking roller should not be too thick, and the roller pressure should be moderate. It is better to print evenly and have no obvious dent on the box surface. Never use the method of increasing the ink concentration and the pressure of the inking roller to improve the printing effect. This will not achieve the ideal purpose, but will lead to the layout paste ink, and the printing quality will be worse, especially for the layout with small text, complex patterns, fine lines, and high overprint accuracy requirements, the disadvantage will be more obvious; The printing locomotive speed should not be lower than 800 rpm, which is too low, the ink on the box surface is uneven, and there is a bottom exposure. Too fast, the ink is too thick, and the layout is easy to blur. At the same time, it is also necessary to prevent paper wool, paper scraps, etc. from entering the printing machine and sticking to the printing plate. If paper scraps are found to stick to the plate, it is necessary to stop the machine immediately and wipe it with a rag dipped in alcohol

second, the printing color should be pure, and the batch has no color difference.

the quality of water-based ink is the key to the purity and brightness of carton printing color, so we should pay great attention to it when selecting. The high-quality ink has no obvious difference with the color code. It feels fine, viscous, and the concentration is appropriate. It is diluted with water or alcohol solvent without sedimentation and caking. There is no foam when stirred with a wooden stick. It is mixed with other inks for color matching. It has good affinity, no immiscibility, and the prepared ink is pure without abnormal reaction. Otherwise, it cannot be used

it is best to finish printing in batches at one time, otherwise, the same barrel of ink will be used, and there will be color difference. The reason is that the original ink is not sealed after being diluted with water or alcohol solvent, and is exposed to the air for a long time. The chemical components in the ink react with the oxygen in the air, that is, the pigment is reduced, and the strong light also has a decomposition effect on the ink

III. prevent more detailed yield point stress curve of Coated Whiteboard from being completely displayed 3 Meet the requirements of future cement detection and change. When printing, overprint and ghosting

Coated Whiteboard paper is manufactured, the coating solution used to coat whiteboard contains glue, and the surface of high-grade whiteboard paper is also coated with a small amount of polishing wax. Therefore, when printing cartons made of whiteboard as face paper, the printing plate will slip at the moment of contact with whiteboard paper. In addition, the pressure of the printing plate is too heavy, and the water-based ink is not easy to penetrate. The ink of the printed carton dries slowly. During printing, continuous operations are carried out, and the printed matter is stacked over and over, resulting in scratches on the surface of the carton to form overprint

to solve this problem, the ink should be diluted with ethanol, not water, because it is not volatile, which is not conducive to the drying of the ink; The printing pressure should be properly reduced, and the printing speed should not be too fast, not more than 600 rpm. An exhaust fan or a hot air drying oven is installed on the surface of the printing machine before stacking

IV. ensure the overprint accuracy

the overprint accuracy first depends on whether the precision of the equipment is parallel to the adjustment of the pushboard in the paper feeding department, and then is the layout production, assembly and correction. Next, we will talk about the overprint accuracy in the layout collage

after the printing plate is finished, take a 0.5mm thick transparent polypropylene plate base, draw a vertical line at the center of its length, and then draw a long, wide and high side line with a small pen according to the specification of the carton to be printed, and then make up the plate according to the sample draft or sample box according to the provisions of the production notice. After the position of the layout is positioned, use a water pen to draw a line according to the edge of the printing plate, then cover the prepared version base of the same size on the version base with the line drawn in advance, accurately draw all the side lines (for example, you can draw another version base for overprint three colors), and finally press the overprint color, and firmly stick the corresponding printing plate to the painted position with neoprene. Then paste the printing plate onto the roller of the printing machine with double-sided adhesive tape, and the center line of the plate base can be aligned and coincided with the center line of the plate loading roller of the printing machine. As long as the position of the mosaic is accurate and other objective conditions are met, the overprint will be accurate

v. the influence of full page printing on the strength of cartons

we know that when cartons are printed, corrugated cardboard is transferred to the slotting part through the paper guide rollers and printing rollers of the printing machine. After being pressed by the rollers in the transfer process, its physical properties have changed to varying degrees, which will inevitably affect the strength of cartons. Full page printing is particularly prominent. The strength of cartons with the same material should be reduced by about 30% compared with those without printing. Therefore, great attention should be paid to the production process, and the following measures can be taken to alleviate it:

first, the gap between the paper guide rollers of the printing machine should be properly adjusted to ensure that the printed cardboard passes smoothly without deformation (it is best to be slightly less than the cardboard thickness of 0.1-0.15mm); Second, the pressure of the printing plate is adjusted to meet the requirements of clear printing, and the hand feeling of the box surface is flat without depression; Third, appropriately increase the speed of the printing machine (more than 1000 rpm) to make the paperboard pass through the printing machine as soon as possible and reduce the pressuring time of the paperboard

VI. the missing version of the carton shall be supplemented in time.

in the actual production of the printing machine without a computer version correction device, due to the negligence of the operator, the phenomenon of word dropping and missing version is difficult to avoid. Remedial measures should be taken in time after similar events occur. If only the slotting and corner cutting have not been nailed, the slotting knife can be removed, the missing layout can be subsidized to the corresponding position, and then the printing plates of other nozzles can be removed to start up and reprint. However, do not drive too fast, otherwise it will cause poor reprinting effect or layout displacement. If the printed carton has been nailed and shaped, in addition to the layout being treated according to the above method, it is also necessary to adjust the gap of each guide roller until the carton passes smoothly without deformation after forming. The pressure of the printing roller should also be adjusted appropriately, and then it should be transferred to the paper baffle to determine the layout position. When printing, it should be transported individually

VII. Precautions for the printing of thin paperboard

the so-called thin paperboard, i.e. D and e thin corrugated paperboard, should be stamped and formed by the flat die-cutting machine after printing. Because the batch is small or the customer only makes it once, and the cost of the die-cutting blade is high, the printing brush is used for slotting and forming during production. In practice, because the paperboard is too thin, the printing speed must be slowed down, but the paper pusher is either difficult to push the paper, or it pushes multiple paperboards into the printing machine at the same time, causing a lot of waste. To solve this problem, you can first use a single machine for slotting, binding and forming before printing, but you need to load different versions according to the two front and side marks of the carton. It takes two times to print a complete layout of the carton

VIII. Warped paperboard should be prevented from running at different temperatures. The plate and slotting should be moved.

for warped paperboard printing, a single sheet of paper should be fed, and the operation should be carried out at a low speed. At the same time, the air suction should be appropriately increased, and the slotting phase of the printing plate should be adjusted in time according to the layout and slotting conditions. Select the cardboard with serious warpage, stack every 3-5 pieces of positive and negative, flatten it with heavy objects for next reprint, or fold it in the opposite direction of warpage along the indentation line for reprint

in a word, we should deal with specific situations flexibly according to objective conditions in actual production. The above opinions are for reference only. Due to the limitation of the author's level, there must be some deficiencies, and I am willing to discuss with my peers

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