Pharmaceutical Packaging: Thermal Transfer Printing and Flexographic Printing

Now, more and more variable information needs to be printed on pharmaceutical packaging. This demand has forced packaging companies to consider thermal transfer printing. Is there room for flexographic printing?

Flexographic printing is the most widely used printing method so far on pharmaceutical packaging. But now, thermal transfer is gradually occupying the flexographic printing market with a rapid offensive. As more and more companies want to become global sellers, in order to meet the requirements of the European market, the product lot must have a lot number and a valid date printed on it, so the type of language printed on the package and the number of common symbols will also follow. Increase. For flexo printing, it is not economical to print different information every time it is printed. In order to reduce costs, some pharmaceutical companies started using thermal transfer printing. Thermal transfer printing has programmable design, the printing method is not constrained by the printing plate, and the advantages such as variable information can be directly called from the database, so that the use of a quick replacement of the flexographic printing.

But not all manufacturers and users of flexographic printing presses have given up this centuries-old printing technology, because some new inks and printing plates are still able to make the flexographic printing a new attraction. Small flexographic presses can provide customers with small batch production services for printing fixed information on packages. After collecting and analyzing the views of domestic and international printing industry experts, Modern Printing magazine concluded that both flexographic printing and thermal transfer are mutually complementary cooperative relationships.

â–  Competition between the two technologies

According to statistics from the Association of Flexographic Printing Technology, about 70% of the films in the $18 billion film processing industry are printed on flexographic plates.

Tolas Health Care Packaging is a supplier of medical film packaging services. The company said that flexographic printing of pharmaceutical packaging is common, this approach is very versatile, the operation forms are diverse, and the price is low, so the company's business is mainly flexographic printing. Another Perfecseal company in Philadelphia, USA, has always used flexographic printing. Mr. Ron Fortunato, the company's printing business department manager, said: “If printed on metal foil, film or DuPont's Tyvek, use thermal transfer thermal transfer. More suitable."

Wazir Nobbee, a senior engineer at the Tyvek division of DuPont, added that the quality of flexo printing on the Tyvek is not only good, but also the printing speed is fast, usually printing from 30m to 40m per minute. Nobbee thinks that flexo printing is more suitable than thermal transfer. He said: "For large-volume printing, this method is very economical. You can continuously print the entire roll of packaging material, not only printing a wide range of images. , And the speed is much faster, very suitable for printing fine stripes or logos. And other printing methods may need stop-and-go, less efficient."

Although flexographic printing is economical and fast, it cannot be compared with thermal transfer when the print content changes. When content or coding needs to be replaced during the printing process, the flexographic printing must change the printing plate, sometimes even need to make a new plate, and the plate making cost of each plate needs about 500 US dollars. However, when the operator changes the text content or the effective date, if the thermal transfer method is used, all they need to do is input the corresponding content on the keyboard and send it to the printer.

Now, printing or packaging companies often encounter such a situation, in the printing process needs to change the printed content, because different market requirements for the product must print a bar code, product lot number or effective date, etc., but also requires printing a variety of text. For example, Medtronic needed to print multiple words on the packaging of its cardiovascular drugs. The annual cost of printing on the plates was as much as $150,000 to $200,000.

Most pharmaceutical packaging companies believe that the main drawback of flexographic printing technology is not speed, but rather the problem of filling packaging when packaging domestic pharmaceuticals. Some experts said that molding, filling and sealing machines are generally intermittent when working, so the ability to have continuous high-speed operations is no longer the deciding factor in selecting printing technology, and the speed of thermal transfer is not like snail crawling. It's slow. For example, Bell-Mark's thermal transfer system uses an edge-type showerhead that prints at an angle and does not print vertically, allowing high-speed operations on substrates of any shape. However, some people think that the cost of thermal transfer is too expensive. An industry source said that "flexo printing is easier and more cost-effective than thermal transfer."

â– New ways of cooperation

Both technologies have advantages and disadvantages. Therefore, the best way is not to force the flexographic printing out of the market, but to use it together with thermal transfer. Using a combination of the two systems allows the user to achieve the respective advantages of both technologies - the use of a low-cost, easy-to-operate flexo system when printing standard information content, and easy-to-program heat transfer when printing variable content India system. Graphic Controls has been using a thermal printer mounted on a blank packer to print variable information on polyethylene. But Noel Gharibian, the company's engineering manager for Devon's product line, said that thermal printers cannot be programmed, so they can only print a limited amount of variable information, so they have to manually replace printed metal letters. After using a thermal transfer printer, the company was able to print information including part numbers, product descriptions, quantities, lot numbers, usage expiration dates, etc., all of which were generated by computer programming.

However, when printing standard information such as company names, contact information, and company logos in multiple languages, the company still used online flexo printing. GraphicControls' new system consists of two thermal transfer print heads mounted laterally on top of the flexographic press. In order to distinguish between variable information and fixed information, the color of the variable information for thermal transfer is black, and the invariant information for printing with flexo is purple.

The combination of the two printing methods is not valid for all companies. Medtronic's Tom Roberts said he wanted a programmable heat transfer machine just like Bell-Mark's thermal transfer printer to get rid of the inks and plates needed for the flexo press. Roberts said: "Ink and plates are troublesome. Even if you don't change the text, you need to change the plate frequently because of the wear and tear of the plate. In addition, when you use two different printing systems, you need to train different technologies. Staff to properly maintain and maintain the press."

â–  Flexo still has a market

Although there have been some criticisms of flexographic printing, the flexographic printing system still has its advantages. Pugh of Bell-Mark Company stated that Flexo Printing helped their company solve the inventory problem of preprinted packaging materials. Installing the cylinder flexographic printing unit online is the most economical way of filling the packaging machine. This is a perfect fit for situations where the content of information changes infrequently.

In addition, flexo printing technology is constantly improving. In the case of printing plates, rubber stampers or laser engraving methods were used in the past, and photopolymers are now used. For example, the flexographic printing plate made by DuPont Cyrel can be well matched with the computer-to-plate (CTP) technology. Its low hardness is very suitable for printing Tyvek, and the printing plate can be well matched with the printing media.

At the same time, in order to meet the requirements of the Environmental Protection Administration (EPA) for reducing the use of volatile organic compounds, users in certain printing fields, especially flexographic printing presses, have begun to switch from using solvent-based inks to using water-based inks. However, material manufacturers must produce a specially formulated water-based ink that adheres to the substrate of pharmaceutical packaging and ensures that it can withstand packaging sterilization and transportation. Tolat's Marotta said that only after knowing exactly how the packaging is disinfected can it be possible to create a stable ink. For example, it must be able to withstand steam sterilization, but whether there is such a universal ink that can withstand any method of disinfection, experts doubt. In general, inks can be versatile, but no ink can meet a variety of needs.

â–  New Challenger Appears Again

In the pharmaceutical packaging and printing market, there is another way that it may become a bigger competitor for flexographic printing. A research report from SRI International stated that pharmaceutical companies should pay close attention to the progress of inkjet printing technology in variable data printing. Eric Shrader, the company's project manager, said: "Inkjet printing can also be controlled by computer programming. We have already made many innovations in developing low-volatile inks that can withstand the sterilization process." He said that the US Postal Service has recently used The inkjet printing system replaces the original flexographic printing system for printing those high density barcodes.

Dale Ploeger, director of R&D technology at SRI International, said that inkjet printing may also solve some of the needs that people have not raised. For example, inkjet printing can be printed on the packaging that is being filled, and thermal transfer printers can only be printed on flat packaging. Currently on the market, there are two inkjet printer vendors that are working on the development of better printing systems. They are Domino and Videojet.

On the whole, although everyone thinks that thermal transfer can replace flexographic printing, this has not actually happened. There are still some companies offering flexographic printing services such as Bell-Mark, Greydon, and KiwiCoder, including various models, high-quality printing, and high-speed printing equipment for small businesses.

Therefore, pharmaceutical packaging companies will generally rely on a printing system with a combination of functions to meet their printing needs. Because for some pharmaceutical companies, this combination is very successful. If it is also able to meet new demands for variable data printing economically and successfully, packaging engineers will immediately apply them to more efficient production lines.

Transfer from: China Pharmaceutical News