Discussion on the Factors Affecting the Glossiness of Offset Printing
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: 860681365@qq.com
In offset printing, gloss has a great influence on the visual effect of printed products, especially color prints, which determines the grade and level of printed products to some extent. So what are the factors that affect the gloss of printed matter? Below we will analyze and discuss it from the following four aspects.
First, the gloss of paper and printed products
Paper is the main factor determining the gloss of a print, including the following:
1. Paper smoothness
The smoothness of the paper is good, and the gloss of the printed product is good; on the contrary, the gloss of the printed product is poor.
2. Paper absorbency
The ink absorption of the paper is too strong, the printing ink binder penetrates into the paper more, and the paper remains less on the surface of the paper. The gloss of the printed product is lower or even dull, because the gloss of the ink is mainly formed by the binder. .
3. Paper strength
The paper has low strength, and the phenomenon of falling off powder and falling hair is serious. When printing, the bonding force between the ink and the paper is not high, and the gloss of the printed product is low or even dull.
Second, the amount of chemicals and print gloss
The amount of chemicals used is also a key factor affecting the gloss of offset printing. Generally, under the conditions that do not affect the transfer and printing of the imprint, the amount of chemicals should be minimized to ensure that the printed products are bright in color, bright in gloss and clear in imprinting.
Third, ink and print gloss
1. Ink leveling
In the printing process, the ink has good leveling property, and the gloss is good; the leveling property is poor, the drawing is easy, and the gloss is poor.
2. Ink mobility
The fluidity of the ink is too large, the size of the blot is enlarged, the dot is enlarged, the ink layer is thin, and the gloss is poor; the fluidity is too small, the gloss is high, but the ink is not easily transferred, which is not conducive to printing. Therefore, in order to obtain a good gloss, the fluidity of the ink should be controlled, and it should not be too large or too small.
3. Ink fineness
The ink particles are rough, and there are problems such as stacking and printing in the printing, the printing is also rough, diffuse reflection occurs, and the gloss is poor. On the contrary, the gloss is good. Pay attention when selecting inks (especially gold ink, silver ink).
4. Viscosity of the ink
The viscosity should not be too large or too small, too much to peel off and draw the surface of the blanket and the printed product; if it is too small, the size of the print is enlarged, and the ink layer is thinned, which affects the gloss.
5. Dry form of the ink
The same amount of ink is in different dry forms, and the gloss is different. Generally, the oxidized conjunctiva is dried at a higher gloss than the osmotic drying because the oxidized conjunctiva is dried on the surface of the ink print having a large amount of binder, and the permeable and dried ink print has less surface binder.
Fourth, printing pressure and print gloss
Pressure is the key to good transfer of the blot. The pressure is too large, the blot is enlarged, and the gloss is weak. If the pressure is too small, the print is not clear, which will cause the print to be dull. Therefore, under the premise of ensuring that the ink on the blanket can be correctly transferred to the printing material during offset printing, the minimum pressure should be used as much as possible to print the glossy printed product.
In order to improve the gloss of the print, the following methods can be used:
1. Jiafan Lishui (No. 0 oil)
The oil has a large viscosity and is thick in itself, and can adjust the ink concentration to thicken the thin ink and increase the gloss of the printed product.
2. Add light paste
The bright paste is processed from raw materials with high gloss, which can increase the gloss of the ink, but the dosage should not be too large, otherwise the drying speed of the ink will be lowered, the sticking and drawing phenomenon will occur, and the gloss will be affected.
3. Adding a fumigant
When some inks are too dark to meet the requirements of spot color printing, they need to be lighter, which not only makes the ink lighter, but also improves the gloss of the print.