Coding technology of flexible packaging.
Traditional flexible packaging coding technology relies on letterpress printing, and uses the characters on the character frame to create images. Images are mechanically imprinted or rolled onto the film surface.
Common letterpress printing techniques include hot printing, wet ink and ink wheel printer.
In recent years, Continuous Inkjet Printing System (CIJ) has also been applied in flexible packaging. Ink-jet coding machine prints various data on primary packaging and paper boxes, including simple date codes, logos, barcodes and serial numbers.
Traditional letterpress printing technology and continuous ink-jet printing system have their own advantages, but they also have many shortcomings, such as the traditional hot carbon ribbon coding machine and ink wheel coding machine can not print in real time, and need to manually update the date and batch number, which limits the traceability; In printing, there is no standard LOGO, barcode or rotary image printing method, and every printed character needs word grain. In production, the hot carbon tape coder needs "warm-up time" before operation, and "cooling time" when changing information, which will prolong the production time. Once the word size is not accurately aligned, the packaging film will be worn out. In addition, the worn or lost characters will make the printed results unreadable, and the length of hot carbon ribbon is relatively short. The average length of domestic carbon ribbon is only 100 meters. Ink of ink wheel printer needs time to dry or may produce stains, and the stains need special cleaning solution to clean. Moreover, most ink wheels need to be preheated (it takes up to 30 minutes to heat the ink wheels and code them) and cooled before changing the code content.