Post-processing technology of glass bottles - pad printing and heat transfer printing technology

1. Introduction to pad printing process
Pad printing is an indirect recessable rubber head printing technology. It is a printing technology that uses a rubber head to transfer the etching pattern content to the product by making a specific steel plate pattern. It has now become a kind of printing and decoration on the surface of various objects. Main method.
Principle: The process is very simple. First, the designed pattern is etched on the printing plate, the etching plate is coated with ink, and then most of the ink is transferred to the printed object through the silicone head.
Main production problems and solutions:
1. Pad printed font burrs: After pad printing, small feather-like burrs appear on the edge of the font, making the font enlarged; the ink is too thin and does not dry quickly enough; the humidity is too high;
Solution: A.Reduce the amount of ink thinner used; make the ink dry faster; B.The rubber head is equipped with a hot air blowing device; C.Reduce the humidity in the workshop and reduce the etching depth of steel plates;
2. Pad printing pattern deformation: Graphic distortion and deformation appear on the surface of the pad printed product, mostly at the edge of the pad printing area; the shape of the pad printing rubber head selected is not ideal; the ink is too thin; the rubber head is deformed after long-term use; the clamp moves ;
Solution: A. Choose a pad printing head with appropriate taper and hardness; B. Replace the pad printing head; C. Adjust the position of the clamp;
2. Application of thermal transfer printing on glass bottles
Thermal transfer film is a technical method that prints patterns and glue on a heat-resistant film, and adheres the pattern (ink layer) and glue layer to the glass bottle through heat and pressure.This process is mostly used on plastics and paper, and is less commonly used on glass bottles.
Process flow: 1. Color draft; 2. Printing film; 3. Thermal transfer; 4. Baking.
Thermal transfer film is generally divided into five layers. The surface PET film layer serves as the carrier, and the separation layer plays a role in being suitable for peeling off when heated.The protective layer plays the role of protecting the ink layer, the ink layer is for pattern printing, and the adhesive layer is the adhesion layer.

Since multi-color patterns can be printed at one time during the film printing stage, the existing patterns can be transferred to the glass bottle at one time during the transfer operation.Compared with the tedious registration of multi-color screen printing, the printing work can be greatly shortened and the material loss caused by printing errors is reduced.At present, labor costs are constantly rising, and customers have high-quality requirements for accurate positioning. Therefore, the advantages of thermal transfer printing are very obvious on multi-color manuscripts.
In addition, in the film printing stage, CMYK printing is routinely used, and spot color printing can also be performed according to customer requirements.The effect of thermal transfer printing is more realistic, the color reproduction is high, and gradient colors can be achieved.Due to the thermal baking of the image, the color of the finished image of thermal transfer printing will be stronger than that of water transfer printing, and will not easily fade. It has good properties such as corrosion resistance, aging resistance, wear resistance, and high temperature resistance.
In the processing of glass bottles, compared with water transfer printing and silk screen printing, the advantages of thermal transfer printing are more obvious.
In general, compared with traditional water transfer printing and silk screen printing, the advantages of thermal transfer printing are: less manpower consumption, high degree of automation, fast, accurate color registration, high yield, and less environmental pollution.However, the disadvantage of thermal transfer printing is that it requires high regularity of the substrate, and the operation needs to be carried out in more regular positions.The processing of square bottles and cylindrical bottles is very advantageous.Special-shaped bottles need to be analyzed based on the entity to confirm the processable position.In the development of thermal transfer printing, in addition to ordinary toner inks, many new types of heat transfer printing films, such as pearlescent ink film, mirror ink heat transfer film, and hot stamping heat transfer film, have also been developed.Looking to the future, the use of thermal transfer printing on glass bottles will become more widespread.