In industrial production, carton printing technology should be used. Today, paper box with magnetic Xiaobian take you to analyze the printing technology classification and characteristics of cardboard boxes.
Small boxes, carton products, often have a variety of structure and layout coexist. For example, there are both pages based on field printing, and printed pages with mesh, text, lines and field patterns coexist; There are gold and silver pages, which cannot display spectral colors, and spot colors and four primary colors. If the use of offset printing, relief printing (or gravure printing, etc.) process of different printing methods, printing products have their own advantages, multi-process combined printing boxes, cartons and other packaging products, can achieve the internal quality of products. Offset printing process printing reproduction effect is good, the tone is soft, the dot is clear, the printing level is rich, printing large area layout is not easy to appear sticky dirty products. The letterpress and gravure printing technology has the advantages of thick and full ink layer, bright color and high gloss. Therefore, using the advantages of different printing processes to print the products with mesh, text, lines and field patterns, as well as the layout of various colors, combining the advantages of different printing methods to print the same product with the "synthesis" process, which can not only give full play to the utilization rate of equipment, but also improve the product quality and economic benefits synchronously.
A variety of reasonable arrangement of printing process
Offset printing process has light printing pressure, relatively small printing deformation value, and the product is not easy to appear sticky dirty bottom phenomenon, so it is suitable for printing color mesh plate, line, small text, negative picture and large area of the field layout.
And the relief printing process can achieve a large amount of ink at one time, more suitable for printing gold, silver ink, field, line or text. From the characteristics of printing, the product ink layer of offset printing process is thin, the ink is easy to dry, and the product does not produce convex marks, does not affect the normal overprinting of relief printing. And the letterpress process of the product ink dry slowly, on the normal color will cause some adverse effects. Therefore, the overprinting sequence of rubber convex combined products is generally: offset printing page first, relief printing page after printing; Small print first, large print later; The ink color with strong covering power is printed first, and the ink color with strong transparency is printed later, such as the black text or pattern overprinted on the red and yellow pages (with the exception of white ink dilution). The black pages can be printed first, and the other colors are printed later, so that the black color can still reveal the pure black color because of the strong transparency of the overprinting color.
Key points of technical control of printing combined with various processes
1. Control the process technology of pre-press design
The letterpress field layout should avoid small Yin lines and text in the same color plate, so as not to take full account of the pressure and ink supply, which is easy to produce paste plate and uneven pressure, affecting the printing quality of the product. The overprint part of the rubber relief surface should be separated as far as possible, so that there is a certain gap around the edge of the overprint page or the edge of the light color page should be properly expanded (so that the edge of the overprint page can be overpressed to cover it), so that the slight overprint is not correct, and the naked eye is not easy to detect.
2. Do a good job in the technical control of the printing process
The part of the page with overprint should be as close as possible to the bite and pull gauge (side gauge), in order to avoid due to the expansion of the paper, the phenomenon of overprint is not allowed. In addition, the layout of the "river" (core) larger or multi-plate color plate, should not be spelled for the use of two kinds of technology respectively overprint.
3, pay attention to the reasonable selection of offset plate material
PS plate has a thin plate, installed to the surface of the cylinder, its envelope Angle is relatively small, the plate elongation is also small, and it can maintain close contact with the cylinder, is conducive to improving the rubber convex product overprinting accuracy, so the offset printing process should choose PS plate printing.
4. Pay attention to the technical control of the printing plate base
Packaging products of small size are often printed by quarto or split circular flat structure relief press. The characteristics of the backing material of the printing plate have a great impact on the printing pressure, overprinting accuracy and ink quality. Traditional wooden base, the material is not solid, square, flatness and stability are relatively poor, prone to bow and deformation, printing quality is difficult to ensure. Therefore, letterpress printing should use solid, flat, square, stable aluminum or cast iron magnetic plate and other gold property material base, which is the basis of improving product alignment and ink quality.
5. Pay attention to the good printing pressure control technology
The printing pressure should be adjusted evenly and moderately. Too much pressure is easy to make the printing sheet stretch and deformation, resulting in inaccurate overprinting. Therefore, the printing pressure of letterpress process must not be too large, and the printing pressure should be as light as possible to achieve ideal printing under the premise of meeting the uniform and full ink color of the layout.
6. Pay attention to the technical control of the wrapping process
Lining is the medium to realize the transfer of pressure and imprinting, and its characteristics also affect the alignment and the quality of ink. Therefore, the deformation coefficient of the lining material should be as small as possible, and the material should be neutral and hard. At the same time, must be strictly in accordance with the technical parameters of equipment specifications, set the thickness of the lining. In addition, the lining must be tightly packed, there is no virtual loose, bulging state, letterpress lining should not be repeated patch or hollow, in order to prevent misprinting and double shadow phenomenon.
7. Pay attention to the technical control of ink and wash balance
To control the balance of ink and wash in offset printing process is to minimize the supply of water solution and print under the condition of maintaining the balance of ink and wash. Should avoid the use of "ink is also large" abnormal balance method for printing, in order to prevent the paper surface due to excessive water absorption and deformation.
8, pay attention to control the temperature and humidity of the printing environment
Controlling the temperature and humidity of the printing workshop is an important part of improving the accuracy of product overprinting. The temperature and humidity of the offset printing and relief printing workshop should maintain a relative balance, and there should be no large disparity. Otherwise, it is easy to cause the phenomenon of inaccurate overprinting. Generally, most small and medium-sized printing enterprises are limited by conditions, unable to effectively and accurately control the temperature and humidity of the production site. They are often controlled by experience through the switch of doors and Windows or the simple method of splashing water on the ground, which can also play a certain role.
9. Pay attention to the technical control before the cardboard is put into use
Cardboard is very sensitive to the temperature and humidity changes of the external environment, especially the white board just produced, the most easy to appear telescopic mutation because of the change of temperature and humidity, resulting in inaccurate overprinting of products. In order to reduce the chance of this happening, the newly produced white board, after the printing plant is transported back, generally after a period of storage, so that the characteristics of the cardboard is relatively stable, put into use is not easy to appear overprinting phenomenon. In addition, the cut board should be sent to the printing shop immediately, so that it can balance the temperature and humidity of the printing shop, and then printing is conducive to improving the precision of the product.
10. Pay attention to the technology of cutting paper
The specification and precision of the cardboard will also affect the overprinting of the product. Because of different machine structures, their pre gauge and pull gauge position is not the same, so that if the edge of the cardboard is not cut square enough, there is a hypotenuse or wavy edge, it will cause the overprint is not allowed. This requires rubber convex combined products, the side of the cardboard must be cut into a right Angle, straight line, there is no hypotenuse or wavy edge phenomenon. In order to improve the cutting accuracy of cardboard, it is necessary to strictly control the thickness of cutting, because the thicker the paper is, the softer the paper is, the more severe the deformation of the paper surface when the paper press down. Therefore, the less the cutting thickness of each stack of cardboard, the more beneficial to improve the cutting accuracy of cardboard. In addition, the blade mouth should also be kept sharp, and according to the hardness of the paper, choose the right blade Angle, which is also an important measure to improve the precision of cutting.
11. Pay attention to the production cycle of product overprinting
When printing the first color or a few colors after printing, can overprint should be immediately overprint, so as not to make the printing telescopic mutation due to too long time delay, resulting in inaccurate overprinting.
12. Pay attention to the protection of semi-finished printing products
The semi-finished products after printing should be sealed with plastic film to prevent the cardboard from absorbing water from the outside air or losing water, so as to avoid or reduce the adverse phenomenon of expansion and variation of semi-finished products.
To sum up, carton, carton and other packaging products, no matter what way of process printing, a printing process alone printing, a variety of processes combined printing worth mentioning; Whether to use multicolor printing presses for printing production, or to use monochrome printing presses for printing production; Is the use of advanced multifunctional printing press for printing production, or the use of simple, ordinary printing press for printing production, no matter what the case, the most important, the most critical link, is to according to the characteristics of the product, control the operation technology and technology, with moderate printing pressure, the use of appropriate ink coating amount for printing; Based on the characteristics of ink, plate and board, the printing quality and production efficiency can be better improved by using the appropriate speed for printing.