Gravure printing tester in gravure ink formulation application

1 Significance of Gravure Printing Tester

Gravure printing ink volatilizes very quickly, the determination of the amount of ink transfer is very difficult, and it is not easy to find the analytical relationship between the amount of ink on the plate and the amount of ink transfer. Therefore, the research on the mechanism of transfer of gravure printing ink still remains in the qualitative analysis. At present, the performance test of gravure printing inks is mainly made by scraping wire rods or scraping by simple testing machines and proofers. Existing wire rods, testing machines and proofers can only reflect part of the properties of printing inks, such as hue. , gloss, abrasion resistance, adhesion, residual solvents, etc., but the ink transferability of gravure ink can not be truly reflected. After thoroughly analyzing the mechanism of gravure printing and the principle of gravure ink transfer, and referring to the construction of intaglio printing presses at home and abroad, we have developed a gravure printing tester. It has been proved that this testing machine can accurately and quickly reflect the thoughts of ink formulation designers and others. The performance of printed materials can save time, labor and cost, and provide powerful guarantee for high quality high-tech gravure products.

2 Principle of Gravure Printing Tester

The gravure printed text image is in the layout. That is to say, the blank part of the plate is all on the same plane (layout), and the graphic part is below the blank part, and the depth of the original image is expressed in the depth of the layout. Such a plate is called a gravure plate. Printing with a copy of an image is called gravure printing.

The level of darkness on the original corresponds to the printed portion of the plate, and its low depth is large; conversely, the portion where the brightest layer of the original is printed on the plate corresponds to a shallow depth. Therefore, the printing portion of the plate expresses the depth and depth of the printed image based on the difference in the depth of ink contained in the depth of the plate.

In the gravure printing process, the ink is not coated on the printed image part like the letterpress and lithography, but the ink is applied on the entire printing plate, that is, the graphic part and the blank part are all inked. In order to achieve the purpose of printing, during the printing process, the squeegee is used to scrape off excess ink from the blank portion and the graphic portion. Then, under the effect of a larger pressure, the ink in the printing graphic portion of the downflow is transferred to the substrate by the capillary suction. If the graphic portion of the printing portion is deep, the amount of the ink filled in is large, and the imprint is transferred to the printing. The ink layer on the object is thick; on the contrary, the ink layer is thin.

3 Application of Gravure Printing Tester

This testing machine is suitable for the printing adaptability and printing effect of printed materials (gravure printing ink, paper, plastic), and can be used by printing ink manufacturers, substrate manufacturers, and gravure manufacturers to inspect various printing materials and printing. The use of effects.

4 Gravure printing machine parameters:

Project parameters

Printing speed 0-150m/min

Printing pressure 8 - 10Pa

Imprinting roller size diameter 120mm, length 300mm

Plate size diameter 130mm, length 300mm

Ink tank capacity 3 liters

Motor parameters 380V, 750W

Printing plate parameters testable ink and substrate substrate

Number of lines (L/cm) Depth (μm)

80 47 Alcohol ink, white cardboard, coated paper

70 60 Metal ink, white cardboard, coated paper

100 40 alcohol ink, glass cardboard

70 39 Water-based ink, white cardboard, coated paper

70 50 Plastic Ink, Various Plastics

5 How to use a gravure tester

5,1 gravure printing machine operating steps

(1) Clean the plate roller, and wipe the surface of the roller with a certain amount of slow-drying solvent with a cotton cloth.

(2) The squeegee is used for sanding and cleaning. The squeegee is polished with sandpaper and a small amount of engine oil and cleaned with a solvent.

(3) Clean the ink tank and pour the adjusted ink into the ink tank.

(4) Adjust the imprint pressure and position the plate roller.

(5) Put down the squeegee and adjust the proper squeegee angle and pressure.

(6) Place the substrate material on the feeder.

(7) Start the proofer and adjust to the required speed, usually around 300 rpm.

(8) Push the feed tray in reverse.

(9) Remove the sheet and check the quality.

(10) Wipe off the remaining ink from the plate roller, squeegee, and thoroughly clean the platen roller.

5、2 Precautions during operation of gravure ink testing machine

(1) After every color of the printing roller, it should be thoroughly cleaned. Otherwise, the remaining ink will solidify in the cell, blocking the network, causing the ink transfer rate to decrease.

Print materials according to printing requirements and select the appropriate printing plate parameters for proofing

6 Application of Gravure Printing Tester

Gravure ink is generally composed of four main parts: pigment, resin, solvent and auxiliary agent. The proportion of each part is determined through experiments. Excellent gravure ink formulation with excellent post-printing properties, such as gloss, vividness, abrasion resistance, dot reproducibility, good film formation, leveling, re-dissolvability, overprinting, proper initial drying And dry, lower residual solvents, etc., and these properties are obtained on the premise of excellent ink transfer performance, while the ink also meet the requirements of modern high-speed gravure printing presses.

The design of the gravure ink formulation is mainly based on the theory of ink manufacturing, through the wealth of practical experience of ink engineers, plus some inspection and operation equipment, such as: detection of viscosity, hue, gloss, abrasion resistance, etc., and then go to the gravure printing factory on the machine test The transfer performance of the ink to determine whether the gravure ink is suitable, and the process is long and wasteful, and the formula risk is high. If the formula is not applicable, it will come back again. This way, not only is it wasteful, it has a long cycle, and it may even Loss of business opportunities, if gravure printing machine is used as a formula test tool in this process, the period of proofing can be greatly shortened and the consumption of proofing ink and other materials can be saved. In the short term, it can produce qualified ink products. Theoretically speaking, the structural parameters of the gravure printing tester are basically the same as the current structural parameters of the unit gravure printing machine. The structural parameters include the perimeter of the printing plate roller, the number and depth of printing lines, and the circumference of the embossing rubber roller. The length and hardness, the angle and pressure of the squeegee, the pressure of the squeegee and the line speed of the imprinting point of the printing plate, from the principle of ink transfer of the gravure printing, these parameters basically determine the quality of the gravure printing product ( The test machine adopts single sheet feeding without printing tension, but the printing tension only affects overprinting accuracy and does not affect the printing effect). In practical terms, our company has used the very successful gravure printing ink on the gravure machines such as Bobst, and achieved the printing effects (including printing hue, leveling, glossiness, etc.) under the same conditions on the gravure ink testing machine. Abrasion resistance, residual solvents, etc.) are exactly the same. In addition, by adjusting the ink formulation, the ink formulation is artificially broken to balance, (by adding the silicone that can cause the ink to produce shrinkage holes, at this time, the black spots on the surface of the ink cannot be seen on the paper by the ink stick scraping. , And through the gravure printing tester can see that there are obvious "black spots", this phenomenon is the cause of shrinkage). Using this formula on a gravure printing tester, the resulting printing effect is also the result of breaking the ink formulation balance.

Through the above comparative analysis, the results of the gravure printing tester are accurate and can be used to inspect the substrate and the printing plate for the formulation of the printing ink, and the printing effect preview provides accurate information.

Generally speaking, in the determination of the ink formulation on gravure machines of gravure printing manufacturers, ink suppliers generally do not change the amount of each component of the formulation, the type of raw materials used, and the manufacturing process, otherwise it will be used by ink manufacturers for production. The risk of goods is very high. Theoretically, there is a possibility of optimizing the ink formulation. Due to the lack of application data of the gravure printing press test, it does not dare to optimize. If a gravure printing tester is used, an optimized formulation system can be achieved and the formulation cost can be optimized. Composition to meet the requirements of the gravure printing company's personalized service. In some cases, gravure printing manufacturers will also have special requirements on the printed products, and the gravure ink formulation should be modified accordingly. At this time, if a gravure printing tester is used as a formula design tool, it can be touched. That is, save time and effort. In addition, the use of intaglio printing testers also plays a key role in the hue control between batch and batch production of spot color inks by gravure ink manufacturers, which can achieve a good level of hue stability.

With the development of society, the gravure ink has also made continuous progress, environmental protection, conservation, resources, energy and many other issues continue to emerge, using gravure printing test machine, can give priority to the development of new products to meet the new requirements of modern gravure printing. For example, gravure gravure printing inks, water-based gravure printing inks, and UV gravure printing inks can be developed by using a gravure printing tester. Information such as plate conditions, printing speed, and ink formulation parameters can be obtained.

7 Application of Gravure Printing Tester

The gravure printing tester can provide accurate and reasonable formula data for the ink manufacturer to adjust the formula and design the formula (the experiment sand mill can make 2 kg of ink).

The gravure tester provides a template for the ink manufacturer to detect ink properties (such as residual solvent content of the print, gloss, abrasion resistance, various resistances, etc.).

The gravure tester can effectively control the color difference between the batch and the batch when the ink manufacturer produces the spot ink.

The gravure printing tester can accurately and quickly reflect the use performance of raw materials in the ink when developing and producing raw materials for ink raw material manufacturers.

The gravure printing tester can provide the co-ordinated and unified data between the gravure printing factory and the substrates, printing inks, printing plates, etc. before printing.

Accurately and quickly provide the basis for the selection of substrate, printing ink, and printing plate parameters for gravure printing manufacturers.

Gravure printing testers can provide effective experimental tools for the theoretical study of gravure printing.

In summary,

The gravure printing tester builds a bridge between printed materials (gravure ink, substrate for printing) and actual printing. With this bridge, the actual process of printing materials and printing can be concise, convenient, fast, and effective.