Flexographic printing (Flexo) is a roll-to-roll printing method used on flexible packaging films such as BOPP, CPP, PET, and PE. This process employs photopolymer plates, anilox rollers, and solvent- or water-based inks to deliver fast, cost-effective printing with up to 8 colors. The key advantage of flexo lies in its high speed and compatibility with various flexible substrates, making it ideal for food, hygiene, and export packaging.
What is Flexo Printing?
Flexographic printing (Flexo) is one of the most widely used industrial printing methods, based on flexible photopolymer plates. In this process, ink is transferred from the anilox roll to the plate, and then the design is printed onto the target surface (film or paper).
Flexo, due to its high speed, ability to print on various packaging films, and cost-effectiveness, has become the standard method in the flexible packaging industry.
Main Components of a Flexographic Printing Press
- Anilox Roll: Transfers a precise and consistent volume of ink to the plate (range 200–600 LPI).
- Photopolymer Plate: A flexible surface with raised patterns where text or images are engraved.
- Print Cylinder & Impression Cylinder: Used to transfer the design onto the substrate.
- Inking System: Distributes solvent-based or water-based inks evenly.
- Dryer System: Ensures rapid ink drying using hot air or IR.
مراحل فرآیند چاپ فلکسو
- Preparing the design file and separating colors (CMYK or Spot).
- Producing the photopolymer plate.
- Mounting the plates onto cylinders and setting register.
- Feeding the substrate roll through the machine and controlling tension.
- Printing colors step by step (4 to 8 colors).
- Drying the inks and rewinding the printed roll.
Substrates for Flexo Printing
- BOPP films, CPP films, PET films, PE and Nylon
- Paper and cardboard
- Aluminum foil laminates
Advantages and limitation of Flexo Printing
Advantages:
- High production speed (150–400 m/min).
- Ability to print on a wide range of materials.
- Cost-effective for large production runs.
- Good quality for food and hygiene packaging.
limitation:
- Lower detail resolution compared to gravure printing.
- Initial cost of producing photopolymer plates.
Industrial Applications of Flexo Printing
- Food packaging (snacks, biscuits, pasta).
- Dairy and beverage packaging.
- Hygiene and pharmaceutical products.
- Export packaging resistant to moisture and light.
Technical Factors in Choosing Flexo
- Number of colors: Usually 6 to 8 for detailed packaging.
- Type of ink: Solvent-based or water-based.
- Register and tension control: To prevent color misalignment.
- Anilox quality: LPI and cell volume directly impact print quality.
Conclusion
Flexographic printing is the most efficient choice for high-volume runs and printing on flexible films. It provides an ideal balance between speed, cost, and quality, making it the backbone of the packaging industry.
FAQ
Q1: What is the difference between flexo printing and gravure printing?
Flexo printing offers higher speed and lower cost, while gravure is better suited for very fine details and higher image quality.
Q2: What are the best materials for flexo printing?
BOPP and CPP films are the most commonly used due to their durability and cost-effectiveness.
Q3: How long do flexo plates last?
Depending on plate quality and production conditions, they can last between 500,000 and 1,000,000 meters of printing.
Q4: Is flexo printing suitable for export packaging?
Yes, because it can be applied to multilayer films that are resistant to moisture and light.
Q5: What is the maximum number of colors in flexo printing?
Depending on the machine model, flexo can handle between 6 and 10 colors.
Q6: What is the speed of flexo printing machines?
They typically run at 150 to 400 meters per minute, with advanced models capable of even higher speeds.