What are the commonly used printing methods for self-adhesive labels
Commonly used printing methods for self-adhesive labels are as follows:
Embossing is used to print self-adhesive labels. The printing plate is a photosensitive resin letterpress. The printing label has the advantage of full ink color. However, the grades of letterpress printing equipment are quite different. Some rotary embossing machines have adopted professional inclined-back, satellite or unit-type self-adhesive label printing machines, so they cannot be generalized during transformation. Professional self-adhesive printing machines mainly embossed have the ability to print film labels, but they need to contact suppliers to replace some related parts, such as adding a tension control system controlled by a servo motor, adding a film surface treatment unit, some The machine can also increase the registration system.
Self-adhesive offset printing
Offset printing is the main way for my country's label printing factories to print paper stickers. Offset printing is characterized by fine graphics and rich layers, suitable for mass printing, and the printing equipment can be used for multiple purposes, which is suitable for the characteristics of the Chinese label market. However, sheet-fed offset printing is not suitable for printing films with non-absorbent surfaces, because film labels are mostly printed from roll to roll and require volatile drying inks. Offset printing can print thicker plastic materials, such as in-mold labels and label hang tags, but it needs to be equipped with a UV curing device for the machine, which requires a lot of money.
Self-adhesive flexo printing
The quality of flexographic printing is no less than that of offset printing, and even has its own unique features. The advantage of this printing process is that the machine structure is simple, the cost is low, the printing quality is comparable to offset printing and gravure printing, and it has the advantage of thicker ink layer than offset printing products. Flexo printing uses water-based ink and UV ink, which does not pollute the environment. However, due to the greater elasticity of the flexographic plate, the reproducibility of the tone is different from that of the gravure and ordinary letterpress. The dots from the highlight to the midtone of the flexographic printing are larger, the printing contrast is small, and the highlight level is prone to faults. When printing fine graphic labels , In order to make up for layer defects, the highlight part can use FM screen, dark tone or mid-call AM screen to improve the quality.
Gravure printing adopts short ink path inking system for ink supply, roll material printing, high degree of automation, using solvent-based ink, the ink layer dries quickly, and is the first choice for film printing. Generally, the gravure printing machine has a high speed, and the rear end of many gravure printing machines is also equipped with a roller die-cutting device, which can perform die-cutting and creasing, and is suitable for printing various labels. However, due to the long period of gravure plate making and the high cost of plate making, it is only suitable for mass label production.
Self-adhesive screen printing
Screen printing is a printing method with wide adaptability to substrates. At present, many screen printing factories use cheap screen printing equipment to undertake the printing business of self-adhesive labels and film labels. The screen printing label is characterized by thick ink color and strong three-dimensional effect, and film products can be printed with uv ink. In addition to several rotary screen printing equipment capable of printing roll-to-roll labels, most of the screen printing equipment is a semi-automatic flat screen printing machine, which can only print single-sheet products, and the overprinting accuracy is not high, so it is not suitable for film label production equipment matched with the production line .
Large-volume printing is mainly based on offset printing, gravure printing, letterpress resin printing or flexographic printing. However, the demand for personalized small-batch self-adhesive labels is increasing in the market. It is a six-fold or eight-fold sheet-fed paper, and some have thousands or hundreds of copies. The web label printing machine is a bit wasteful when printing this kind of job, which is not cost-effective.
From the perspective of printing products, small batches require low cost and short delivery time; while product quality often requires bright colors, and most of the hierarchical layouts are composed of dots. According to this situation, many small printing companies use six-color single-color offset printing machines for four-color overprinting, which also achieves very good results.
In offset printing, letterpress printing, gravure printing and other printing, offset printing is undoubtedly the printing method with lower cost. In the pre-press process, compared with the complicated plate-making process of the flexographic plate, the production, production, and printing process of the PS plate are familiar to the printing factory. From a technical point of view, all printing houses have turned to offset printing after eliminating printing, so there is no additional burden.