Analysis of Characteristics of Laser Holographic Aluminized Paper Printing

Aluminized paper is easy to laser holographic processing, vacuum aluminum paper after treatment is called laser spray aluminum paper (referred to as laser paper). The laser sprayed aluminum paper is formed by loading a laser holographic pattern or text signal onto the surface of the sprayed aluminum paper by means of molding. The laser brightness of the laser sprayed aluminum paper is several times stronger than that of a conventional laser packaging machine'target=_blank>transparent film, and the laser pattern cannot be wiped off. Moreover, the laser sprayed aluminum paper has a relatively complicated production process, high technological content, and large investment in equipment. Making fake and shoddy products prohibitive, so laser spray aluminum paper has a very good security.

For the use of aluminized paper, each printing company has summarized some of its own experience in the production process. This paper aims to discuss the solutions to the problems we encountered and the issues that should be paid attention to in material procurement.

In the process of using aluminized paper, we generally use gravure and offset UV printing and screen printing. The following are some of our concerns and solutions in the printing process:

1. Vacuum aluminum-plated paper should not be stored for a long time. It is better not to exceed two months. Because a long time the surface will stick to the back of the paper, causing the paper surface to bloom, which is what we often say "fall light" phenomenon;

2. Cracking of aluminized paper is a problem that has frequently occurred in the past. Sometimes it is not discovered until the time of delivery, which results in the rejection of the entire batch of products. Today's paper basically has no such problem, but it is more serious if problems arise. In order to avoid quality accidents in this area, the stability of the material should be tested after it has been placed for a period of time. This type of crack, which looks like a turtle pattern, may be caused by the coating of varnish on the surface of the aluminized paper and the inadaptability of the ink. It can be analyzed by the ink factory and the paper supplier.

3, after printing, ink bursting and shedding phenomenon occurs, if this problem occurs, the general solution in printing is to make the water-based varnish before the UV printing; second is to increase the thickness of the ink layer by using the special color block to increase the thickness of the ink layer twice. Fold resistance; Third, try to choose high toughness ink. It is also necessary to consider the surface coating varnish used in the production of aluminized paper, such as the polar reaction of the ink and the surface coating varnish, and it is also prone to ink burst, which should require the paper supplier to the surface The composition of the varnish is adjusted. Some aluminum coated paper manufacturers believe that the use of appropriate anilox roller coating uniformity, the paper surface tension increased to 38 dyne, to a certain extent, solve the problem of gravure ink adhesion.

4, for UV offset ink adhesion fastness, there are two main situations, one is printed in the ink after printing the ink to pull off; Second, after the print on the surface of the ink layer is not easy enough to pull off. Solution: The former suggests increasing the UV curing intensity between color groups or using wet and wet overprinting to complete the curing process at the delivery site at one time; the latter can use high-toughness UV curing ink and adding special varnish to the ink. Adjust its viscosity.

5, aluminum coated paper for light reflection, hue control is difficult, the choice of ink to consider its coverage, the rational use of adjuvants. Ink transfer considers the color reduction effect of the background color, and pays attention to the hue change after drying and polishing, so that the hue of the batch package can be controlled within the acceptable range of the customer.

6. The color arrangement of printing should generally highlight the main style of the design. In the printing, the color of the first printing and the color of the after printing are different due to the color sequence. The effect is also quite different; the absorption performance and drying from the aluminized paper In view of the specificity of performance, it is recommended that multicolor printing presses should follow the following points: Colors with dark colors and small areas should be printed in advance; generally, the background color of large areas should be placed on the last printing. Such as the first printing a large area on the ground, will cause the back of the color overprint is not on, but also easy to scratch the back of a few colors in the back of the printing, scratching the surface of the background color, resulting in a decline in product quality, affecting the appearance and design effects. The main colors should be printed at the back. In general, completely transparent ink does not exist, the hue of the printed product tends to favor the hue of the post-printing color; the color of the overprinting accuracy should be printed first. Because aluminum-plated paper has the dual physical properties of metal and paper, it should be printed on the front with a high-precision color. In the design of the process, it is necessary to fully consider that the lines of printed products must be matched with the packaging production line to avoid unnecessary losses.

7, aluminum-plated paper absorption is poor, the paper is easy to curl, to strictly control the workshop's temperature and humidity, if the environment can be printed during the temperature and humidity and material, ink, machine pressure, moisture and other factors to be properly controlled, can reduce paper Deformation. In addition, it is possible to back coat the product during printing and change the curl direction and amplitude by the amount of back coating.

8. Aluminium-coated paperboards have poor wear resistance, poor stiffness, and poor handling during die-cutting can directly lead to poor molding of cigarette marks. During die-cutting, die-cutting plates must be produced according to the characteristics of aluminum-plated paper, and marks and lines should be properly used. The bottom mold, so that the packaging does not have a strong rebound force, the mark is not exposed.

9. Aluminized cardboard material is more brittle and easy to break than coated cardboard. The indentation line is easy to burst. Our current method of factory inspection is to fold the finished product three times, and we will continue to consider it as qualified. This method has strong operability and can basically meet the requirements of the tobacco packaging machine.

10. The odor problem of finished aluminized paper products is more prominent, especially UV screen printing. Eliminating odor is also an important aspect of aluminized paper products. The printing time can be lengthened, and forced ventilation can be added to the ventilation equipment and workshops at the printing site. Some manufacturers now also use vacuums and other methods to eliminate finished odors.

11. The problem that the bar code scanning does not pass through the current printing of aluminized paper has plagued many cigarette label printing companies, but it has not affected the development of aluminized paper products in tobacco plants. Therefore, we are required to be able to better solve this problem. In the case of offset printing, many manufacturers use two or even three times of printing to solve this problem, or use screens, gravure printing, and other methods to do white printing. Gravure printing, flexo printing, etc. are basically not available. The problem, so we should take into account the printing process when developing the product.

12. The issue of seam seams in reel printing and aluminum spray paper printing is currently the biggest obstacle to the wide application of laser sprayed aluminum paper. At present, many equipment manufacturers in the world are making unremitting efforts in this regard and have made certain progress. If this problem can be solved comprehensively, it will have an epoch-making impact on laser jet paper printing. To solve the problem of avoiding seams, the author believes that the concept and control method adopted by Wuhan Jincai Technology from the beginning of paper production to the print registration are excellent solutions that can be considered in the intrinsically connected printing equipment.

In a word, as the leader of packaging printing, cigarette marking printing has emerged in an endless stream. With the increasingly higher requirements for environmental protection, composite aluminum foil paperboard and PET laminated paperboard paper are being gradually phased out. Environmental protection, aesthetics and anti-counterfeiting The need to reduce costs and export requirements has led to the increasing use of aluminized paper in the printing of cigarette markings. This requires us to continue to raise awareness of it, and more mastering of the printing of aluminum-coated paper will certainly give our business belt. More opportunities and room for development.

Reprinted from: Graphic Arts