Talking about the Selection of Corrugated Box Printing Methods

Printing is a technique for copying the manuscript text. The reason why the production of graphic and graphic documents on corrugated cartons adopts the printing method is mainly due to the fact that the printing has the characteristics of being able to accurately and quickly reproduce graphic and text, and can be printed in large quantities and economically. The use of different printing methods can maximize the various requirements of the carton for printing.

Various printing methods have their own process characteristics. The printing of the corrugated box can be selected according to the quality requirements for the printing, such as the accuracy of color registration, the degree of consistency of the ink, the amount of printing, the period of printing, and the process of printing in the corrugated box manufacturing process.

The corrugated paperboard is made by pressing the corrugated paper into a corrugated shape, and then bonding the cardboard on both sides with an adhesive to make the paperboard a hollow structure in the middle. The structure has a large strength, can withstand a certain pressure, is flexible, has a strong cushioning property, and can play a role in preventing earthquakes and protecting commodities. At present, corrugated paperboard uses direct flexographic printing, screen printing, and indirect offset preprinting and gravure preprinting.

1. Offset printing corrugated carton

There are many forms of lithography, of which offset printing is the most common one. Offset is to transfer the image on the printing plate first to the offset roller, and then to the printing component, which belongs to indirect printing.

Offset printing has the advantages of simple plate making process and low cost. It is not only suitable for printing some exquisite pictures, but also can print some books with rich pictures and pictures, and has high production efficiency. It is a printing method with more advantages in the printing field. Offset printing is used in carton printing for both transport packaging and sales packaging. Either stand-alone production or the production of corrugated cardboard production lines can use offset printing. The choice of offset printing mainly depends on the production volume, production cycle, and printing requirements of corrugated boxes.

Sales packaging is different from transportation packaging. It not only requires printing some necessary marks, but more importantly, beautifies the goods. Printing has become an important means of decorating goods and propagating goods. China's sales packaging mostly uses color offset printing. The requirements for printing mainly depend on the type of goods, the quantity and size of packaging. The process of color offset printing can be arranged either before or after the production of corrugated cardboard, but printing on raw paper is the most common.

The conventional offset printing corrugated carton adopts an indirect printing method, that is, printing the cardboard face paper first, and then attaching the printed face paper to the corrugated board. Due to the relatively high resolution of the PS version, a very fine printing pattern can be printed. At present, the vast majority of high-grade corrugated box printing used for sales and packaging in China is offset printing.

Offset printing corrugated boxes have the following characteristics:

(1) The printing products are very fine, and the number of screens can reach 150-200 lines/inch.

(2) Plate making is easy, and the PS plate is normally plated.

(3) It is not suitable to use paperboard linkage production line. It is only suitable for single-faced corrugating machine and the production efficiency is low.

(4) Limited format, generally smaller than flexo carton format.

(5) Can finish the surface decoration, such as laminating, polishing and so on.

(6) High printing costs.

(7) The printing quality is relatively stable.

The direct offset printing process of corrugated cartons has been relatively mature abroad. It is the printing of corrugated cardboard directly onto a special offset press. Suitable for processing thin corrugated boxes.

The process can not only guarantee the good formability of the carton, but also can complete the exquisite glossy paper printing. However, the printer used is expensive, and the process may become the development direction of high-grade corrugated box printing in China.

2. Flexo printing corrugated carton

Flexographic printing is the use of a flexographic printing plate to print by means of an ink transfer roller, which is a type of relief printing process. The printing plates used by them are all raised in graphic parts. During printing, the anilox roller applies a certain thickness of ink layer evenly to the graphic portion of the printing plate, and then under the pressure of the impression cylinder, the ink layer of the graphic portion is transferred to the surface of the substrate to form a clear graphic. .

Relief printing on corrugated cartons often results in a certain degree of damage to the corrugated cardboard boxes due to the relatively large printing area, which affects the compressive strength of the cartons. Secondly, when the screen version is used, the quality is difficult to control. The effect is: It is not ideal. Printing on corrugated cardboard or cartons currently uses flexographic printing that has evolved from letterpress printing. The general letterpress printing is only used in the production of a corrugated cardboard box in a stand-alone manner for printing text or trademark on a sheet of paper prior to creping.

The conventional flexo printing corrugated box process is directly printed on the corrugated board. Water-based ink is used. Corrugated board printing in China uses ink. This is because: the corrugated board has a simple text design and does not require high gloss; Cardboard paper, loose structure, strong ink absorption, water-based ink printing is conducive to penetration and drying; water-based ink is non-toxic, odorless, and non-flammable, it will not affect product quality, but also easy to use and safe, low cost .

Corrugated board color flexographic process can be summarized as: graphic design → image processing → plate making → printing → die cutting → box.

With the continuous improvement of flexographic printing technology, more and more flexo printing methods are used on corrugated cardboard. The printing method has the following advantages:

(1) The flexographic printing press has a simple structure, a low cost, a price that is only one-half that of an offset printing press or gravure printing press, and is easy to operate online with other processing equipment. Generally, the corrugated board area is large, and the length can reach 2~3m. If other printing equipments are used, huge equipment is needed and it is difficult to operate and maintain. However, the flexographic printing machine has a simple structure and can be used in other processes such as indentation and slotting die cutting. , gluing, box making, etc., are combined together for online continuous operation.

(2) The elastic deformation of the flexographic plate can compensate for the thickness error and uneven surface of the corrugated cardboard during the printing process, so that the printing ink is uniform, thereby improving the printing quality and strength of the corrugated cardboard.

(3) Flexographic printing uses an anilox roller for ink transfer, which facilitates water-based ink transfer, and the plate needs only light contact with the corrugated board, and the aqueous ink is almost completely absorbed.

(4) Printing plates are easy to handle during loading and unloading, and less material loss. It is suitable for the printing of large-volume prints.

(5) Because of the uneven thickness of the corrugated board, the pressure on the paper surface is inconsistent throughout the printing process of the general method, the thick part of the print is pasted, and the thin part is not in contact with the imprint. Flexographic printing belongs to light printing pressure, and its pressure is small, which is only 1/30 of that of traditional letterpress printing. Even if the printing plate is compressed and deformed, it can contact corrugated cardboard well.

(6) Flexo can not only use small-format printing, but also can be used for large-format printing of webs.

Flexographic printing corrugated boxes should pay attention to the following issues: avoid full-page printing; text should be clear; ink color saturation; consider the actual ink parameters, dot gain and other parameters; consider the different lines of the dots, the width of the flexo printer, and the printing slot Machine, and the impact of different materials and pressures, etc. The flexographic plate direct printing process is suitable for the production process of the first type carton, and is currently widely used in the carton factory in China.

3. Screen printing corrugated boxes

A screen-printed plate is a screen with many through holes. The image on the manuscript is made with a through hole in the printing plate. During printing, the ink is directly attached to the printing member through the screen plate under the pressure.

Screen-printed plates can be flexible plates, so they can be used for curved prints with their specific range of applications. The printing features are thick ink layer, good color and graphics, rich three-dimensional sense, simple plate making and low cost. Screen printing includes copying plates, stencil holes, and silk screens widely used in domestic corrugated box factories.

The screen printing corrugated box process uses direct printing. Since the ink ratio of the screen printing plate is proportional to the hole pitch of the screen, the resolution of the screen printing is not high, the image accuracy is low, and the number of conventional screen lines is 60-80 lines/inch.

Corrugated board printing using screen printing, the process flow is as follows: Original design - positive negative film - screen template - corrugated board printing - die cutting slot - a nail box or sticky box.

Screen printing corrugated boxes have the following characteristics:

(1) The printing can be completed before the pairing or boxing, or after the pairing and boxing.

(2) Suitable for printing non-fine products. The screen printing ink is thick, so its color saturation is high and the visual effect is strong, especially the spot color printing effect is better.

(3) It is not suitable for the linkage production line and the production efficiency is low.

(4) The printing format can be large or small.

(5) Plate making is easy and plate making cost is low.

(6) Low printing costs.

(7) The quality of printed matter is relatively stable.

However, the screen printing efficiency is generally low, the color printing is difficult, and the color expression performance is poor. Mainly used in small batches or stand-alone production of corrugated boxes.

Gravure printing corrugated box

Gravure printing is mainly used in a new type of printing box method for gravure preprinting in corrugated box printing.

4.1 Plastic Gravure Composite Carton Process

When using a single-faced corrugated production line, if a glossy film needs to be applied after the face paper is printed, and the production volume is large, it may not be printed on the face paper, but a gravure printing method is used to complete the gravure printing on the plastic film, and then Conventional carton forming process box.

The characteristics of this process are:

(1) The cost of carton production is low. When the production volume is large, such a process can greatly reduce the printing cost of the tissue paper and the material cost of the tissue paper. Because the noodle paper does not need to be printed, non-coated white paper can be used, so that the cost of the noodle paper is greatly reduced.

(2) beautifully printed. Because plastic gravure is used, the printing effect can be comparable to that of offset printing.

It is necessary to pay special attention to the fact that in the process of plate making, it is necessary to fully consider the dimensional change and deformation of the plastic film. Otherwise, the carton face paper will be misaligned with the lower cardboard.

4.2 Coated paper gravure printing composite carton process

When the production volume is relatively large, no coating is needed, and the printing effect is good and the cost is low, this process can be used.

The process is to use a paper gravure printing machine to print thinner coated paper first, and then composite this fine-printed coated paper with the cardboard, as a whole, as a cardboard box, and then carry out the confrontation and normal carton forming process.

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