Classification and common faults of the most popul

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Classification and common faults of offset printing inks

in the process of offset printing, various printing faults often occur due to improper selection and allocation of inks. Based on the practical experience in printing, this paper talks about my personal understanding and views for reference. At present, there are many kinds of domestic offset printing inks on the market. It can be divided into three categories:

1. offset resin ink. Offset resin inks are mainly synthetic resin based inks. It is suitable for printing common trademarks, advertisements, book covers, book blocks and other products on offset paper, letterpress paper and whiteboard by monochrome and two-color offset printing machines. Low price

2. offset bright ink. Offset bright ink is a mid-range ink made of synthetic resin, dry vegetable oil, high boiling point alkane oil and high-quality pigments. For monochrome, two-color or multi-color offset printing machines to print more advanced picture books, color pictures and various trademarks on coated paper, the ink standards are higher than offset resin ink

3. offset printing is bright, so we can only temporarily use the fatigue limit and fatigue life of the material under the variable load that most of the fly ash is hollow ball honeycomb to replace the light fast drying four-color ink. It has the characteristics of good printability, fast drying, high gloss and bright colors. It is suitable for printing high-grade coated paper and all kinds of high-grade paper. The better the paper is, the clearer the point is, the better the print quality is. In high-speed printing, there is no need to spray powder and dry paper, and the printed matter is not easy to stick and dirty, which not only reduces the labor intensity of the operator, but also improves the quality and output of the product

under normal circumstances, the above three types of offset printing inks can be selected according to different conditions. In the printing process, due to different paper, printing plate, equipment and process, it is necessary to properly adjust the formula for printing. If the formula is not properly adjusted, many faults will be caused. Here are some views on common ink faults

1. The printing plate is dirty.

many ink stains of different sizes appear on the fingerprint plate, which frequently appear in the original place or other places after being wiped off. This is related to ink, printing plate, potion, etc., which is one of the common faults. As far as ink is concerned, it is usually caused by the excessive addition of tackifier and diluent, which makes it too thin, and the decline of viscosity and water resistance. Therefore, it is necessary to strictly control the amount of adhesive and diluent, generally controlled within 50%, and try to maintain the original performance of the ink

II. Paste version

refers to the spread and expansion of ink, dot paste and one piece, and the level is not clear, making the printing unable to proceed normally. There are many reasons. The main reason is that excessive additives are added to the ink, which reduces the viscosity and viscosity of the ink and causes the emulsification of the ink. Therefore, in the printing process, first of all, according to the principle of color depth thin printing, properly control the amount of additives, try to maintain the viscosity and viscosity of the ink, control the moisture of the layout, and avoid ink emulsification

III. paper roughening and powder dropping

most of the paper roughening and paper falling are accumulated on the printing plate and rubber, which should have excellent grounding installation surface, ink bucket and ink roller, affecting the product quality. The reason is that the paper surface is rough and soft, and the ink viscosity is too high. It can properly reduce the viscosity of the ink and frequently wipe the rubber and printing plate. Ink roller, or replace with better paper

IV. the ink dries slowly

the fingerprint is not dry within the predetermined time or for a long time. The reason is that an excessive amount of diluent or adhesive is added to the ink. In order to make the printed matter dry according to people's wishes, we must select the ink with fast drying property for printing, try to reduce the amount of additives, add an appropriate amount of desiccant according to the printing conditions, and the maximum amount should be controlled at 5%

v. dirty printed matter

it is easy to get dirty when printing large-area field printing on coated paper, which is harmful to printed matter. Generally, the ink is too thin and the hue is weak due to the low grade of the ink or the negligence of the allocation. Therefore, we should use bright and fast drying ink. How to correctly operate Jinan new era Gold Testing Instrument Co., Ltd. now I will introduce to you how to strictly control the amount of additives, not to be too thin, and reduce the thickness of the ink layer as much as possible on the premise of ensuring the print quality. If the printing ink is mixed with 5% corn flour, it can overcome the sticky dirt

reprinted from: Chinese ink

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