Quality classification and inspection method of th

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Quality classification and inspection methods of paperback album

the printing process is the process of ink transmission and transfer. In order to transfer and transfer the ink according to the needs of the offset printing process and achieve accurate reproduction of the imprint, it is necessary to strictly control the printing suitability of the ink and the inking device

basic requirements:

1. Understand the composition of ink and printability; Understand the characteristics and use of common ink auxiliaries

2. Master the color characteristics of common offset printing inks and the basic principle of mixed color; Master the basic method of mixing ink and the proportion and mixing of several common spot color inks

3. Understand the structure of the inking device and master the adjustment of the ink roller pressure

4. Understand the structural principle and general operation of the ink control device

5. Be able to correctly judge and deal with common ink transfer faults

10.1 ink blending

according to the color needs of the original and the requirements of the printing process, mixing two or more primary color inks in a certain proportion, or adding various auxiliary materials to the ink is called blending BENEC Changshun automotive interior material Zhang Lianghua ink. Its purpose is to obtain new hue inks and change the printability of inks to meet the needs of printing. Inking is an important process of offset printing. It uses the principle of pigment subtraction to organize colors to achieve the purpose of reproduction. Therefore, mixing ink is not only an optical phenomenon, but also a specific reflection of the color change law. Generally speaking, ink blending can be divided into two process parts: the hue blending of ink color (the blending of spot color ink) and the printability blending of ink

10.1.1 basic requirements for blending ink:

1. The hue of the blended ink must meet the requirements of the original or printing sample

2. The tinting force of the diluted color ink meets the printing requirements and has an appropriate ink layer thickness

3. The viscosity and fluidity of the ink meet the printing needs

4. Under normal printing conditions, the imprinting can be timely dried

5. The amount of ink allocated meets the printing demand, which can be slightly more than the demand

6. When mixing ink, the principle of "matching the same type and mixing the same type" should be followed to minimize the number of ink used

10.1.2 selection of offset printing inks

there are many kinds of inks used in offset printing inks, with different hues, properties and application ranges. Therefore, the correct selection of ink is very important to ensure the quality of printing products and reduce costs variety

offset printing inks are divided into two types: flat paper offset printing inks and web offset printing inks according to the type of offset printing machine. Common offset printing inks for flat paper include ordinary resin offset printing ink, bright resin offset printing ink, fast fixing resin ink, fast fixing bright resin ink, etc

domestic ink models are composed of one Chinese pinyin letter and five Arabic numerals. The Chinese phonetic alphabet represents the type of printing plate. Among the five Arabic numerals, the first and second digits indicate the type, performance and purpose of ink; The third digit indicates the ink color; The third digit and the fourth digit are connected together to indicate the ink color hue; The fifth digit represents the decor serial number to distinguish different decors of the same type, such as:

P 01421 offset bright sky blue ink P 02301

Decor serial number tone Decor

sky blue green ink

offset resin ink

lithographic ink

offset rotary ink "03", offset four-color ink "04"

the model of ink general auxiliary agent is composed of one Chinese pinyin letter and three Arabic numerals. The letter code is represented by "F", the first and second Arabic numerals are connected together to represent the characteristics, purpose, composition, etc. of the auxiliary agent, and the third digit represents the design color of the auxiliary agent. For example:

F 9066 ink blending f 920 diluent

Decor Decor

ink blending oil diluent

auxiliary agent auxiliary agent

white oil is represented by "93", debonding agent is represented by "94", anti drying agent is represented by "95", and drying agent is represented by "96" the three primary colors of the combined

ink are yellow, magenta and cyan. Theoretically, the three primary colors can be mixed in different proportions and ways to get different colors. But in practice, no matter how to match, you can't match pure black. Therefore, yellow, magenta, cyan and black four-color printing inks are mostly used in color printing. For printing materials with special hue requirements (such as trademarks, decorations, etc.), it can also be solved by color matching (spot color)

because there are many kinds of four-color inks, different kinds of four-color ink combinations have certain differences in hue, which can be selected and used according to the combination recommended by the manufacturer. If Shanghai Peony brand quick drying bright ink is used, the general standard is magenta, medium yellow, sky blue and black. Japanese and European general standards: dark red, medium yellow, malachite blue, black. Kodak standard: magenta, medium yellow, malachite blue, black

10.1.3 allocation of ink hue

1. Analyze the color of the original or print

if the original sample is attached with a color sample, you can refer to the monochrome sample ink color during allocation. If not, find a place on the print that can represent the monochrome for reference. You can also ask customers to choose the color samples that meet the requirements from the ink samples used by the printing factory

when analyzing hue, the principle of "subtraction method" can be used to consider. Generally speaking, one primary ink is the main color, and the other is the auxiliary color. For example, when preparing green ink, use yellow ink and blue ink to mix. If green tends to be yellow, yellow is the main color and blue is the auxiliary. But before preparing, consider which yellow ink and blue ink are more consistent with the hue. If dark blue and dark yellow are used, the green ink will be red, and the color will be dark. If you use light yellow and Malachite blue or medium blue to mix, you can get a more fresh and tender green ink hue with yellow. Theoretically, the three primary colors add up in equal proportion to get black, but the printing ink's three primary colors add up in equal proportion, and the blackness is not enough. A small amount of light emitting blue can be mixed into the ink. In addition to theoretical guidance, practical experience is very important in the allocation of ink. For beginners, you can prepare chromatography for reference or prepare your own ink samples; Self made primary color ink phase diagram, color basic ten color diagram (three primary colors, three colors, four colors) and so on are helpful to master the color matching

2. Select the ink allocation scheme

in addition to the selection of offset printing ink mentioned above in this chapter, we should also pay attention to the post-processing conditions of prints and the recognition of printing conditions. Based on the design of ink blending formula and the determination of the number of main color ink and auxiliary color ink, the proportion and dosage of main and auxiliary ink are roughly calculated, and then blending is carried out

3. Blending

(1) blending of dark ink

only use primary ink to blend without any diluent. Deployment put the main color ink (the largest amount of color ink, except for equal proportion mixing) into the ink tray, and then gradually add the auxiliary color ink. After blending evenly, use two small pieces of paper (usually coated paper or offset paper) dipped in a little ink the size of Rendan to make a small color sample, watch whether its hue meets the requirements, and watch the difference between its hue and the primary color sample by comparison. It can be viewed with the help of a magnifying glass. Generally, the prepared hue can be slightly darker than the original, so that the color of the ink just conforms to the original when it is printed after the action of liquid medicine and drying. Note down the proportion and quantity for next use. Table 10.3 shows the hues of intermediate and multicolor inks prepared with primary inks for reference

(2) formulation of light ink

all inks formulated by adding diluents are collectively referred to as light ink. Be careful not to add diluent to the original ink to prepare. Because the primary color ink has strong color developing ability in diluents, and the coloring power of each primary color ink is different, generally black> Red> Blue> yellow, it is easy to cause inaccurate hue and waste ink. It should be prepared by gradually adding a small amount of primary ink into the diluent. And most of them try to adjust a small amount first, and then expand the allocation according to the proportion of ingredients after the hue meets the requirements

the content of the primary color ink in the diluent is generally settled with the remaining amount. For example: use black ink to mix light gray. The preliminary hue analysis is 10:3. First weigh three liang of black ink, put it aside, and gradually add it to a kilo of diluent. After the hue meets the requirements, weigh the weight of the remaining black ink. If it is five coins, the ratio of diluent to black ink in the light gray ink is 10:2.5, that is, 4:1

there are three methods of blending light ink:

the first is the dilution method based on vitamin oil, white oil, diluent, etc. The light color ink prepared by this method has certain transparency, no hiding power, and the ink color is not bright. It is suitable for the overlapping overprint of ink, and plays a role in making up for the lack of main color level and tone. It is generally used for light red, light blue, light gray ink, etc. to supplement the tonal atmosphere and level of red, blue and black versions

the second: the anti tone matching method based on white ink. The ink prepared by this method is toned and powdered. The ink color is fresh and has strong hiding power. It is easy to stack plates and blanket when printing. It is suitable for monochrome expression, not suitable for superimposed overprint, and has poor light resistance. The most

Table 10.3 the original adjustment is suitable and fixed tightly; (4) With the development of the experimental machine industry, the production of the experimental machine has moved towards the scope of interchrome and multicolor hue tables

to arrange the post press processing of polishing or film coating

the third is the mixing method of white oil, vitamin oil and other white inks. Visible white ink has different hiding power and transparency with different dosage

10.1.4 precautions for ink color phase allocation:

1. Try to use a few varieties of inks for color matching, and it is best to choose basic inks (basic colors are available in all manufacturers)

2. We hope to achieve the deployment between similar colors close to the hue ring (color ring)

3. Add ink in the order from light to dark

4. Add ink in the order of large to small according to the mixing proportion, that is, add a small proportion of ink to a large proportion of ink

5. Complementary ink (control the color that has the greatest impact on the blending ink color) should be added bit by bit while waiting for the final confirmation of the blending color

6. Appropriate diluents should be selected according to color samples. Such as light red --- mainly with vitamin oil and diluent, slightly with peach red or orange red. Pink --- mainly white ink, slightly pink or orange. Light blue --- mainly with vinylic oil, slightly with pore blue. Lake blue --- mainly white ink, slightly hole blue. Light blue, light red, Matt; Pink and lake blue are bright and bright

10.1.5 adjustment of ink viscosity

1. Increase the viscosity of ink

when the following situations occur, the viscosity of ink can be appropriately increased:

(1) improve the adhesion of ink on paper

(2) control the emulsification of ink and overcome floating dirt

(3) reduce the penetration of connecting material on the paper, prevent oil seepage and powdering, and increase the gloss of imprinting

(4) the viscosity of inks with large pigment ratio and coarse particles should be appropriately increased

(5) prevent "stacking" failure

adjustment method: add No. 0 inking oil. The dosage shall be controlled within 3% - 5%

2. Reduce the viscosity of the ink

in the following cases, the viscosity of the ink can be appropriately reduced

(1) paper with loose tissue and weak combination of fiber and fiber or fiber and filler

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