Board book with pull and push cards and windows
Paper Type: white board
Surface Finish: Film Lamination
Binding: Folded Leaflet
Color: Four Colors, 4+4 color
Age: 3 up
Transport Package: Export Cartons on Pallets
Origin: Shenzhen China
Product Type: Board Book
Printing Type: Offset Printing 4+4color
Book Cover: Hard Cover
Type: Early Learning
Tips of printing:
Printing dirty plate and ink viscosity
1. Dirty plate In plastic gravure printing, a thin layer of resin (encapsulated pigment in the resin) is adhered to the non-printing surface of the drum, that is, a layer of ink is often adhered to the non-printing surface of the plate cylinder. And transferred to the substrate, so that the print presents a sheet or line of dirt, which is the dirty version (also known as the fog version) failure. The cause of the dirty plate problem is mainly related to the viscosity of the ink, in addition to the blade (including the hardness of the blade, the blade pressure, the contact angle of the blade), the quality of the plate, and the ink formulation. If the viscosity of the ink is too large, the viscosity of the ink becomes large, and the materials such as resins and pigments have poor fluidity, cannot be uniformly dispersed, and are easily deposited. The pigment in the ink is unevenly distributed in the ink system, or the resin in the ink fails to wrap the pigment particles well, so that the pigment particles re-aggregate to form a larger pigment group (ie, coarse phenomenon). Under the relatively high-speed movement of the scraper and the plate, the scraper and the plate are easily damaged. These larger particles are easily formed into linear or strip-shaped cut lines during printing, and linear stains occur. Further, since the resin or the like is also in a supersaturated state, a large amount of resins are agglomerated together, and the affinity of the resin to the drum. Under the blade pressure, the resin adheres tightly to the drum (the pigment is entrained in the resin), so that the sheet is dirty. Under the high-speed movement of the printing plate, the ink also exerts a large impact force on the squeegee, so that it is difficult for the squeegee to smoothly scrape off the ink of the non-image portion to produce a dirty plate.
In general, the smaller the viscosity of the ink, the less susceptible it is to dirty problems. However, if the viscosity of the ink is too small, the content of the organic solvent in the ink is large, and the components such as the resin and the pigment are relatively small, so that a smooth film layer cannot be formed in the dry coal, and thus whitening and lack of luster. If the printed product needs better gloss, it is generally necessary to consider using a larger ink viscosity (13~19 seconds, Zahn No.3 cup), that is, the resin and pigment components are relatively more to meet the needs of the printed product. . But pay special attention to the dirty version caused by the large viscosity. In addition, when the ink is printed on the plastic and becomes an ink film, the coated pigment should be firmly adhered to the plastic surface, and the resin is the main material for the firm adhesion of the plastic. Therefore, the firmness of the pigment is also related to the viscosity of the ink. This means that the ratio of the resin and the pigment in the ink should not be too large or too small, but should be within the normal range, and the firmness of the pigment bonding can meet the requirements. Under the condition of maintaining normal environmental humidity, the viscosity of the ink is above 16 seconds (Zahn No. 3 cup), and static electricity generally does not occur. The viscosity of the ink is below 16 seconds (Zahn No. 3 cup). As the viscosity becomes smaller, electrostatic phenomena such as whisker, striated, edge repulsion, flying ink, poor transfer, and extremely irregular water stains will follow. And increase. Therefore, in the actual printing process, special attention should be paid to the change of the viscosity of the printing ink, the viscosity should be adjusted in time, and the quality of the printed product should be improved.
2. Flying ink When high-speed gravure printing (speed exceeds 20 m / min), if the gravure ink uses a domestically produced chlorinated polyene resin with a wide molecular weight distribution, resulting in too low viscosity of the printing ink, it may be The problem of flying ink. The reason for this is that the viscosity of the printing ink is too low. The cohesive force of the ink is greatly reduced. When the ink is transferred to the printing film, the low molecular weight resin is easily separated, and a small ink dot can be seen in the blank portion of the printed matter. To solve the problem of flying ink, we mainly start from two aspects: one is to use a chlorinated polypropylene resin with a narrow molecular weight distribution; the other is to appropriately increase the viscosity of the ink according to the printing situation.
3. Effect on color, transfer rate and color saturation Gravure ink is transferred to the printing substrate by means of the recessed dot ink, and the volume of the printing dot is relatively fixed. As the viscosity of the ink increases, the viscosity of the ink also increases, and the more ink is transferred from the dot, so the color density and saturation of the printed product are higher, but there is a limit. When the viscosity of the ink is continuously increased to a certain extent, the transfer rate of the ink is also increased synchronously. If the viscosity of the ink continues to rise, the viscosity of the ink becomes stronger and stronger, and the ink begins to hardly enter a small amount. At the outlets, the inks in the outlets are getting less and less, and the ink transfer rate is gradually decreasing. The color density of the prints also began to decline. Therefore, in the actual printing process, in order to achieve a good printing transfer effect, the viscosity should be used with great care.