On the performance and binding process of the hott

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Paper performance and binding process (Part I)

in addition to the common relief and offset paper, the paper for binding books and periodicals also includes cover paper, ring lining paper, book back paper, etc. For the commonly used paper, it is not only necessary to understand its types, but more importantly, to understand the performance of the paper used, so as to better select the paper for various processing and achieve the desired results, otherwise there will be defective products or waste products, resulting in waste

1. Paper and use. Paper, commonly known as white newspaper, is often used in the printing of newspapers, periodicals, magazines and general books and periodicals. It is one of the papers that are often touched in the binding process

(1) paper raw materials and paper properties. The paper-1 test software can not be used. It is usually made of more than 90% ground wood pulp and less than 10% bleached chemical pulp. The raw materials used for paper are mainly broad-leaved wood. In order to save wood, some also use some stem materials, such as bagasse, grass, etc; Generally, no sizing is applied during processing, and only talc powder and whitening agent are added appropriately

paper is one of the paper types with large consumption in the printing industry. Due to raw materials and processing, this kind of paper is easy to turn yellow after being stored for a long time or exposed to the sun. Generally, it can be used for more than 100000 times and is brittle. Therefore, it is not suitable for making books that need to be preserved for a long time. It is often used for printing newspapers, comic books, periodicals and low-end books

(2) paper specification. Paper can be divided into web paper and flat paper. The length of web paper is about 6000m; There are four types of width: 787mm, 781mm, 1575mm and 1562mm. Generally, there are two types of flat paper: 1092mm × 787mm,1092mm × 78lmm。 The national standard (gbl910-89) divides the paper into four grades according to the product quality level, namely a, B, C and D. among them, a and B are suitable for printing newspapers on high-speed rotary printing machines; A and other products have reached the international advanced level; B and other products are domestic advanced products

there are many kinds of paper quantification, and the paper quantification in China is developing towards low quantification. In the past, the ration was 52g/m2 for a long time. In the early 1980s, foreign countries generally began to produce 49G/m2 paper, which has dropped to 45g/m2 in recent years. Low quantity paper can save raw materials and freight, save energy, and reduce postage for newspaper delivery. With the improvement of papermaking technology, China has also begun to produce low weight paper. According to the national standard (gbl910-89), there are 51 ± 2 ~ 3G/㎡, 49 ± 2 ~ 3G/㎡, and 5 ± 2 ~ 3G/㎡ in November

(3) precautions for paper binding

① any folding machine can be used for paper folding, and it can be folded up to four times (notch is required); When the book is folded by hand, the third fold shall be cut to remove the air and avoid wrinkles after the book is folded

② after the pages are printed and the books are processed, they should not be placed in the sun or next to the heater or in a wet place to avoid the paper discoloration, brittleness or inequality

③ the paper adhesive should not be too thin (because the paper gap is large and easy to seep), and the adhesive shall prevail

④ the thickness of iron wire stapling is 15mm at most and 0.5mm at least

⑤ when cutting books, the cutter α Generally, the angle can be 20 ~ 23 °

2. Letterpress paper and its use. Relief paper, also known as relief printing paper, is generally used for printing books and periodicals by relief printing machine. Letterpress is widely used in the printing of books and periodicals in China. Almost all books and periodicals use letterpress paper

(1) raw materials of relief paper and properties of relief paper. The main raw material of letterpress paper is bleached chemical pulp of stem fiber. When making paper, it can be used without sizing or slightly sizing. It can also be used with some mechanical wood pulp to improve the making performance of relief printing paper and increase the ink absorption, compressibility and opacity of the finished paper. The pressure of letterpress printing is large, so there are certain requirements for the compressibility of letterpress paper. Adding an appropriate amount of ground wood pulp to the pulp can increase the compressibility of the paper

relief paper is superior to paper in terms of uniformity, smoothness, water resistance, compressibility and opacity

(2) letterpress paper specification. Relief paper can also be divided into web paper and flat paper. The web is generally 6000m long and 787mm, 850mm and 880mm wide. The width of flat paper is 1092mm × 787mm,1168mm × 850mm,1230mm × 880mm。 The tolerance range of width and deflection specified in professional standards is ± 3mm. The weight of relief paper is generally 50 ~ 60g/㎡

(3) precautions for letterpress paper during binding. Letterpress paper is commonly used for binding books and periodicals. Generally, the specifications and standards used for processing are mostly based on letterpress paper

① any kind of folding machine can be used for folding, and up to four folds (notching) can be folded; When folding four fold manually, cut the seam of the third fold to eliminate the air in the book to ensure that the book is flat and free of wrinkles after folding

② the maximum thickness of iron wire stapling is 15mm, the minimum thickness is 0.5mm, and the diameter of iron wire is 0.5 ~ 0.84mm

③ a wide range of binders for letterpress paper. Letterpress paper is easy to adhere, and the viscosity of adhesive is easy to adjust

④ cutter during cutting α The angle is the same as the paper

3. Offset paper and its use. Offset paper, also known as offset printing paper, is a kind of high-grade printing paper, which is generally specially used for book or color printing by offset press. Offset paper can be divided into single-sided offset paper and double-sided offset paper, as well as super calendering and ordinary calendering

(1) raw materials of offset paper and properties of offset paper. Offset paper is generally made of bleached chemical softwood pulp and an appropriate amount of bamboo pulp. When processing offset paper, filling and sizing are heavy. For some high-grade offset paper, surface sizing and calendering are also required

offset paper needs good water resistance, dimensional stability and strength because it adopts the principle of water ink balance during printing. Offset paper is mostly used for color printing. In order to restore the tone of the original with ink, it is required to have a certain whiteness and smoothness

offset paper is generally used for printing picture books, color illustrations, trademarks, covers, ring linings, high-end books and this book. In recent years, due to the improvement of people's culture and living standards, books and materials are also developing to high-grade. More and more books and periodicals and books are printed with offset paper. Due to the advantages of offset paper, such as white, crisp, flat and delicate, the text of books and periodicals is clear, and the books and periodicals are flat and not easy to deform after being made. Compared with letterpress and paper books and periodicals, the grade is particularly different, which has won the welcome of readers and users. The number of books and periodicals bound with offset paper will increase greatly in the future to meet the needs of the market

(2) specification of offset paper. The specification of offset paper is the same as that of the above two kinds of paper. For other specifications, please refer to the national standard gbl47 size of base paper for printing, writing and drawing. The size error and skewness shall not exceed ± 3mm

there are many kinds of quantitative offset paper, generally 60, 70, 80, 90, 120, 150, 180, 200, 250G/㎡. The offset paper for printing books and periodicals is less than 90g/m2, and the cover paper is between 70 ~ 200g/m2

offset paper has the characteristics of straightness and smoothness, and is easy to assemble and process

(3) precautions for offset paper binding

① any method can be used to achieve a good effect of page striking tidiness

② any folding machine can achieve good folding effect, especially suitable for high-speed folding

③ offset paper books and periodicals shall be designed with less than three fold pages (four fold pages shall not be designed). It is better to cover the book after double folding (more than 80g/m2), because the offset paper is thick, the quantity is large, and the number of folds is too many. The book post is easy to have zigzag folds or dead folds that are not easy to unfold, resulting in uneven book cuts and unequal quality of book blocks after cutting

④ when the number of pages or thickness of iron wire is the same as that of letterpress paper, increase the diameter of iron wire

⑤ the viscosity of the adhesive is larger (thicker) than that used for letterpress paper, because the offset paper has a large amount of weight, smooth surface, low viscosity (thin), so it is not firm or falls off after sticking

⑥ the hardcover book block of offset paper is not easy to be rounded and ridged, especially when the paste is thick. Because the offset paper is slippery, it is easy to expose each book post after rounding, and the front opening is in a ladder shape; At the time of ridging, the creases in the creases cannot be smoothed due to manual smashing, resulting in defective products

⑦ offset paper is generally of high grade when making books and periodicals, so the cover material should be better than the book block material to match the inside and outside of the book

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