The difference between diluent and white ink

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On the difference between diluent and white ink

in the allocation of offset printing ink, people often use white ink and diluent. However, white ink and diluent are obviously different in offset printing due to their different properties, so operators should not confuse them; White ink should not be used as a diluent. Offset white ink, which has the characteristics of ink

diluent, as an auxiliary agent of ink, generally refers to viride oil, gloss paste, diluent, etc. They are colorless. In daily printing production, diluents are often used together with inks

there are great differences between white ink and diluent in offset printing

I. role in ink

1 Function of white ink: adding a little white ink to the color ink can change the hue of the ink. The ink with white ink can turn the original ink into a tender and soft jade color. Especially in the packaging printing products, the designers of printing products are always willing to use white ink to make the printing products feel elegant and beautiful, so as to meet people's visual and psychological needs, so as to improve the quality of the packaged products

2. Function of diluent: the diluent machine should be selected from the manufacturer Jinan new period gold testing instrument Co., Ltd. and transferred to the color ink, which can change the depth of the ink. In order to meet the needs of different degrees of color, people get different shades of ink by changing the proportion of diluent in the ink. Obviously, the more diluent is added, the lighter the ink color will be formed

II. Addition proportion in ink

although white ink and diluent are added to color ink to play a corresponding role, they are different in addition proportion in ink due to their different specific gravity

1. White ink addition proportion: white ink is the ink with the heaviest proportion in common offset printing inks. In offset printing, the ink can reach the print surface from the ink bucket, mainly because the ink blending oil in the ink is combined with the pigment particles to drag the pigment particles to transfer under the action of external force. In this sense, inking oil plays a role in carrying color particles. If the color particles are heavy, the carrying capacity of the inking oil will be insufficient, and the ink can not be dragged unless there are specific requirements for the control mode. In other words, a small amount of pigment particles are stuck in place due to immobility. Under the action of printing plate moisture, the carrying capacity of inking oil is more affected. Therefore, when using white ink, the heavier ink pigment particles are easy to be partially retained on the plate surface, resulting in rough and uneven quality problems. For this reason, under normal circumstances, the proportion of white ink in color ink is generally not more than 20%

2. Adding proportion of diluent: diluent that plays the role of diluting ink color has a light proportion and good printability. Its adding proportion in color ink is unlimited. It can be added at will according to the needs of printing color

diluent has ideal ink transfer rate

III. emulsification problem

1 white ink: like other inks, white ink itself has certain anti emulsification performance. After being added to color inks, the water resistance of mixed inks will not be reduced, and the anti emulsification performance of mixed inks will not be reduced

2. Diluent: due to the composition of diluent itself, its water resistance is relatively weak. Therefore, when the diluent is mixed into the ink, the water resistance of the mixed ink decreases, that is, the ink is prone to emulsification. The greater the proportion of diluent added to the ink, the easier emulsification will occur. This should be noted

IV. printing process

due to the different proportion and water resistance of white ink and diluent, their process treatment is also different in printing

1. White ink: when white ink is added into color ink in proper proportion, it will not cause great changes in the printing process

if too much white ink is added, too many pigment particles will be deposited on the surface of the printing plate. Therefore, during the printing process, the printing plate must be cleaned with gasoline frequently to ensure that the imprinting is smooth and uniform

2. Diluent: due to the poor anti emulsification ability of diluent, the following problems should be paid attention to when using light color ink containing diluent

a. the adhesive force between the easily emulsified ink and the printing plate is poor, and the printing plate is prone to plate melting under the erosion of water. Therefore, a certain amount of ink must be kept during printing to prevent plate melting

b. the ink that is easy to emulsify means that water is easy to enter the internal structure of the ink. Such ink is printed on the paper, making the imprint difficult to dry and easy to produce sticky dirt. Therefore, corresponding anti sticky dirt measures must be taken in the printing process

c. the ink that is easy to emulsify is generally not easy to produce dirty plate and paste plate during printing, so it is appropriate to maintain a small page moisture during printing to produce a better printing effect, and a small page moisture can effectively reduce the emulsification degree of the ink

v. post press reaction

comparing the products printed with ink containing white ink and ink containing diluent, the color changes of their respective prints after a period of time are different

1. Post press reaction of white ink: white ink is not easy to fade, but white ink will turn yellow under the action of moisture in the air of various curves such as light and air selectable load deformation and load time. Obviously, when the white ink is transferred to the color ink and printed on the paper, this phenomenon will also be shown. The original immature and bright impression will also turn yellow after a period of time

2. Post press reaction of diluent: diluent is colorless. When the diluent is combined with the color ink to form a light color ink that is just printed on the paper, it can give people a bright feeling. However, after a period of time of absorption of the ink by the paper, the thickness of the printed product will change, and the original impression will change to dry and dim, affecting the color effect of the printed product. When printing on paper with rough surface, this change is particularly obvious

VI. independent use problem

white ink: white ink has a certain hiding power. In view of the performance of the above white ink, it is generally not used alone

diluent: diluent has no hiding power. It can be printed separately to meet the special needs of printing products. If the printed matter needs moisture-proof and anti ink layer falling, the diluent can be printed in the last color sequence. The colorless diluent film seals the ink layer, so that the water in the air is not easy to enter the ink layer and the inside of the paper, which has a moisture-proof effect. The ink layer is not easy to fall off when the printed matter (such as cigarette shell) is rubbed by hand. At the same time, the final color sequence printing with diluent alone can change the surface flatness of the printed ink layer to change the reflection state of light, making the ink layer of the printed product appear brighter and deeper

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