What are the ways of self adhesive label printing?

At present, the global self-adhesive label printing can be divided into five camps according to the different printing methods used.

1.Mainly flexographic printing, North America is a typical representative of self-adhesive labels printed with flexographic printing as the leading technology. The main equipment is a small and medium-sized unit type printing unit, mainly ink, using roll-to-roll printing, circular pressure and circular die-cutting method, with high production efficiency, advanced technology and in line with environmental protection requirements.

2.Embossing and flexographic printing are mostly processed in Europe, the application of flexographic printing is basically the same as that of the United States, letterpress printing also accounts for 50% of the proportion, and letterpress printing all use UV ink, and most of the equipment is stacked or satellite. The material processing method is also roll-to-roll printing.

3.This method is mainly embossed, and this method is mainly in the Asia-Pacific region. Developing countries in the Asia-Pacific region are the majority, label printing is still relatively backward, even if letterpress printing is used, but only a few use UV ink equipment, most of the label printing still uses resin ink, roll-to-roll printing and sheet-fed printing coexist; Due to the high proportion of manual labeling, sheet-fed offset self-adhesive labels are widely used; In the die-cutting method, it is mainly flat-pressed die-cutting.

4.Offset printingOffset printing is the main way for label printing factories in China to print paper self-adhesive. Offset printing is characterized by fine and rich layers, suitable for mass printing, and the printing equipment can be used for multiple purposes, which is suitable for the characteristics of China's label market.

However, sheet-fed offset printing is not suitable for films that do not have absorbent printing on the printing surface, because film labels are mostly roll-to-roll printing, which requires volatile dry inks. Offset printing can print thicker plastic materials, such as in-mold labels and label tags, but the machine must be equipped with a UV curing device, which requires a large amount of money.

At present, there are many screen printing factories that use low-cost screen printing equipment to contract self-adhesive label and film label printing business. Screen printing labels are characterized by strong ink color and strong three-dimensional effect, and film products can be printed with UV ink. In addition to a handful of rotary screen printing equipment that can be competent for roll-to-roll label printing, most of the screen printing equipment is a semi-automatic flat screen printing machine, which can only print a single product, and the overprint accuracy is not high, which is not suitable for the film label production equipment supporting the production line.

For example, when printing self-adhesive labels, the post-press processing of self-adhesive is divided into sheet-fed paper processing and web paper processing according to the application form of the label.

Self-adhesive refers to a composite material printed with paper, film or other special materials as fabrics, coated with adhesive on the back, and coated with silicone protective paper as the backing paper

In terms of product form, it is a composite single-page print, and the back is coated with adhesive, which can be glued to the place where the customer needs to be bonded.

In terms of printing methods, self-adhesive printing usually adopts screen printing, and in recent years, due to the development of offset printing technology, self-adhesive printing also adopts offset printing. It is necessary to produce and make plates before printing.

In terms of post-press processing technology. It needs to go through the necessary cutting, and when the design has special needs, some special processing technology will be added, but in general the complexity is not large.

Self-adhesive labels usually appear on the surface of the article, such as article instructions, bar codes, **labels, **labels, etc., because the back of the self-adhesive comes with a layer of adhesive, so it is very convenient to take it, more and more stores and shopping malls use self-adhesive labels to change, publicity, etc., so how are self-adhesive labels printed?

The first step of self-adhesive label printing is to typeset according to the content you need, usually with CorelDraw or AI software to make, because the picture produced by this software is a vector drawing, even if it is a very small font printed out very clearly, if it is made with PS software, it will form a pattern, printed will affect its effect, the correctness of the use of software is also the first point to pay attention to in self-adhesive label printing.

After the production software is determined, the size of the size should be considered, because the large number of self-adhesive printing will reduce the cost, but also need to consider the size, then it will involve plate making, because the size of different printing machines is not the same, such as 8k, 4k, 2k, etc., if the size selected is just larger than the fixed size of the printing machine, it is necessary to use a larger size to print, or when it is much smaller than the fixed size of printing, both cases will leave a large number of blanks in the printing process and cause the waste of printing. It is a waste of paper and an extra cost, and when you don't understand it, you can go to a special printing house to consult or let someone else design the plate.

In the design, self-adhesive printing is black and white, some are color, printing is usually called four-color, because the color of the printing process is not the same, in the preparation of the plate, start to produce the film, black and white only need to make a plate, commonly known as film film, printing can be completed once, the cost is relatively much lower, and the four-color self-adhesive label printing is designed in the design, in the film needs to press C, M, Y, K that is, black, red, yellow, blue four primary colors each out of a version, In the printing process also need four times of printing, after the first printing, the other three times are called overprint, need to coincide with the position of the first printing, will print out the color of the design, if the overprint is not good, there will be a lot of ghosting, affecting the visual effect of self-adhesive labels, so four-color printing requires a high printing technology, of course, it is also relatively much higher.

After the printing is completed, it is cut according to the designed size, some are regular round, rectangular, and some are special-shaped self-adhesive labels, at this time, the common shape can be cut directly, if you encounter a special-shaped knife, you need to determine the knife in advance, and then according to the final shape of the printed matter to make the knife before cutting, in the self-adhesive label printing process, the more processes involved, the more expensive it is, but the unique design works can better win the attention of customers, Achieve the effect of publicity.

You can get it for free

Self-adhesive lithography is mostly a flat-pressed off-line die-cutting process. Usually, after the die-cutting is completed, it will be manually discarded or the overall multi-template layout will not be discarded, and it will be directly handed over to the customer for disposal. Therefore, for documentary work, the fracture of the die-cutting cutting line should be sampled, and whether the cutting marks caused by continuous cutting or uneven tangent line are not smooth.

When the self-adhesive label die-cutting line appears burr, the installation of the die-cutting knife should be adjusted, indicating that the knife position has different shades, resulting in the pressure of the knife is large and small, so some places are cut off and some are not cut, and the uncut places produce a connection phenomenon. When the die-cutting knife edge is defective, there will also be local joints. In the printing process of non-monoglue labels, it is necessary to make the ink coated on the printing plate can be clearly transferred to the surface of the substrate.

There must be sufficient printing pressure. However, the applied printing pressure should not be too large, too large printing pressure will make the substrate continue to deform, the imprint becomes coarse, the dots are graded, and the paste plate will affect the clarity of the plate. Obviously, the increase in printing speed will have a great impact on the printing plate, which will accelerate the wear of the printing plate, resulting in the partial loss of dots.

When the printing pressure is insufficient, there is no sufficient and reliable contact between the printing plate and the blanket, and the imprint will become shallow, affecting the clarity of the printing plate. The ink color of the blot becomes lighter. At first, it was thought that the printing pressure decreases due to the increase in printing speed, but when the printing speed increases, it is not.

Because when the printing speed increases, the embossing time decreases, the compression time on the surface of the printed matter decreases, and the amount of ink transferred to the surface of the substrate also decreases, and the density decreases. This results in a lighter ink color of the blot. In actual production, in order to compensate for this defect, the method of increasing the printing pressure is often adopted.

Self-adhesive label printing, also known as self-adhesive printing, trademark printing, is the use of a certain printing method to print the label into a self-adhesive material, the printed finished product can be removed, pasted on the goods or packaging to identify it. The common technologies of self-adhesive label printing include embossing, flexo, offset, gravure and screen printing.

Professional self-adhesive printing machines based on embossing have the ability to print film labels, but they need to contact the best business to replace some related components, such as increasing the servo motor controlled tension control system, adding film surface treatment sheets, and high-end machines can also increase the precision registration system. In addition, the power of the UV light source should also be adjusted appropriately.

At present, the quality of flexographic printing is not inferior to offset printing, and even has its own unique place. The advantages of this printing process are that the machine structure is simple, the cost is low, the printing quality is comparable to offset printing, gravure printing, and has the advantage of being thicker than the ink layer of offset printing products, flexo printing uses water-based ink and UV ink, and does not pollute the environment.

Offset printing is the main way for label printing plants to print paper stickers. Offset printing is characterized by fine and rich layers, suitable for large-scale printing, and the printing equipment can be used for multiple purposes.

Gravure printing adopts a short ink path ink delivery system to supply ink, web printing, a high degree of automation, the use of solvent-based ink, the ink layer dries quickly, is the first choice for film printing. Generally, the speed of gravure printing machines is high, and the rear end of many gravure printing machines is also equipped with a cylinder die-cutting device, which can be die-cut and indented, which is suitable for the printing of various labels. However, due to the long cycle of gravure plate-making and the high cost of plate-making, it is only suitable for large-scale label production.

Screen printing is the most widely adaptable printing method for substrates, at present, there are many screen printing factories using low-cost screen printing equipment to contract self-adhesive label and film label printing business.

Printing pressure has a great influence on print quality. Maintaining a uniform and constant printing pressure in the effective printing area can not only make the ink color of the printed matter uniform and the color difference small, but also make the imprint size stable. Flat-flush presses are designed to achieve maximum printing pressure.

However, due to the problem of manufacturing accuracy and plate flatness, and the thickness of the self-adhesive substrate cannot be completely uniform, the pressure is uneven, which affects the printing quality. One of the measures to solve the uneven pressure is to make a liner, and if the pressure is small, the lower part of the workbench will be cushioned; One is to appropriately reduce the hardness of the flexoplate. However, reducing the hardness of the flexographic plate is limited, if the flexible hardness is too low, it will expand the geometric size outward, making the small font easy to blur.

When printing in a large area, the problem of printing pressure is not easy to solve, so we borrow the method used in hot stamping, that is, a layer of 175-line anilox and 90° hardness silicone rubber plate is padded on the workbench, which can solve the problem of exhaust and insufficient local pressure. Sometimes there will be cloud-like shadows on self-adhesive products, which is mainly caused by uneven ink uniformity. The ink roller of the flattening self-adhesive printing machine is a chromium-plated iron roller with a diameter of 150mm that can be axially serialized, and its function is to receive ink from the ink fountain roller and the ink transfer roller and mix the ink evenly, and then transmit it to the ink roller, and the ink roller loses the ink string effect and is easy to form a halo.

In addition, the inking roller is made of soft nitrile rubber vulcanization, if you do not pay attention to maintenance, the inking effect will decrease, it will also cause vignette, and the solution of vignette is to solve the problem of uneven ink uniformity, and the amount of ink can be increased appropriately.

Can other prints print self-adhesive labels? Yes, you can ask for it. Other print shops can often print self-adhesive labels as well.

Self-adhesive labels are a common type of label, which is widely used in various product packaging, logistics and transportation, barcodes and other fields. Printing factories usually provide self-adhesive labels of the same material, size and shape according to customer needs, and provide corresponding design and printing services. It should be noted that different types of self-adhesive materials are suitable for different application scenarios, and customers need to choose according to their actual needs when choosing.