Laser printing used for packaging

The importance of printing to the product

On weekdays, we always talk about the consumption period, the service period, and the topics of food safety. All of the above information will be printed on the packaging. There have been manufacturers who caused the entire product to be returned to the factory due to the expiration date of the printed product. This example shows that the printing on the packaging has a very important role. Many food company's workshops also installed camera sensors to check all the goods. It can be seen that they are spending huge amounts of money on printing.

We often see the use of gravure or offset printing methods on the packaging manufacturer name, product name, ingredient list and other content. These are called source markings. For consumers, they are all kinds of information to convey goods, as well as highlight the brand of goods, thereby increasing consumer confidence in the goods. In addition, the term of use on the packaging and the manufacturer's inherent symbols, which are called direct markings, are printed when the product is finally packaged, and are important for the safety and standardization of the product. In the past, printing, ink-jet, and thermal transfer methods were used for printing (see Table 1). Nowadays, laser printing has been widely used.

Packaging-oriented laser printing

The laser printing technology itself has long been used as surface cutting and printing in the surface of metal parts and electronic parts. Laser printing methods that can be adapted to packaging applications use carbon dioxide gas as part of the method. They are mainly divided into two types. One is the use of laser irradiation energy to carbonize the surface of the irradiated part, and the other is available beforehand. After the ink layer printed in the field was removed by laser, the method of tracing the text was revealed. These practices are mainly carried out on cardboard boxes and thicker resin surfaces. They are characterized by the absence of special consumables and reduced operating costs.

However, there is a problem that when the surface of the irradiated portion is carbonized, carbon dioxide gas is inevitably generated, and in addition, the cutting blade may become dusty when the printing is used.

Faced with the above problems, dust collectors are currently used to deal with them. In the packaging of pharmaceuticals and foods, they should be carried out in cleanrooms. However, the market hopes to develop dustless laser printing methods. The current method of imprinting, which is printed on the surface, cannot negate the fact that the printed content will become blurred due to friction or stain. In addition, in the existing food packaging, soft packaging using plastic film is the mainstream, it may damage the packaging substrate. Therefore, the laser printing method using carbonization or cutting described above cannot be said to be very suitable for the use of flexible packaging products.