Introduction to Print Misregistration in Flexographic Printing
What is Flexographic Printing?
Flexographic printing, often referred to as flexo, is a form of rotary web relief printing that uses flexible photopolymer printing plates. It's widely used in the packaging industry for printing on various substrates, including paper, plastics, metallic films, and corrugated board.
Understanding Print Registration
Print registration refers to the precise alignment of different color separations or print elements on a substrate. In multicolor printing, each color is typically applied separately, and these colors must align perfectly to create the intended image or text.
What is Print Misregistration?
Print misregistration occurs when the different colors or elements of a print job do not align correctly. This can result in blurred images, color shifts, ghosting effects, or visible gaps between color areas. In severe cases, it can make text illegible or drastically alter the appearance of printed graphics.
Importance of Proper Registration in Flexo Printing
Proper registration is crucial in flexographic printing for several reasons:
Quality: It ensures sharp, clear images and text, which is essential for product packaging and labeling.
Brand Integrity: Misregistration can alter logos and brand colors, potentially damaging brand perception.
Regulatory Compliance: In industries like pharmaceuticals and food packaging, misregistration could lead to illegible or incorrect information, violating regulatory requirements.
Cost Efficiency: Poor registration leads to increased waste and reprints, driving up production costs.
Common Signs of Misregistration
Blurred or double images
Color fringing around text or image edges
Unintended color mixing or overlapping
Visible white gaps between color areas
Inconsistent print quality across the substrate
Factors Affecting Registration in Flexo Printing
Several factors can influence print registration in flexographic printing:
Mechanical Factors: Including press setup, gear quality, and cylinder eccentricity.
Material Factors: Such as plate quality, substrate properties, and ink characteristics.
Environmental Factors: Including temperature, humidity, and static electricity.
Operational Factors: Like press speed, tension control, and operator skill.
The Impact of Misregistration
Misregistration can have significant consequences:
Increased Waste: Misprinted materials often need to be discarded.
Higher Costs: Due to wasted materials, longer setup times, and potential reprints.
Reduced Productivity: Time spent troubleshooting and correcting registration issues.
Customer Dissatisfaction: Poor print quality can lead to rejected orders and lost business.
10 Common Causes of Print Misregistration in Flexographic Printing
1. Improper Plate Mounting
How it happens:
Plates are not aligned correctly on the plate cylinder
Incorrect plate thickness or improper cushion selection
Solution:
Use precision plate mounting equipment
Implement standardized mounting procedures
Ensure proper plate and cushion selection for each job
2. Worn or Damaged Gears
How it happens:
Normal wear and tear over time
Improper maintenance or lubrication
Use of incorrect gear materials
Solution:
Implement regular gear inspection and maintenance schedule
Replace worn gears promptly
Use high-quality, wear-resistant gear materials
3. Incorrect Anilox Roller Pressure
How it happens:
Improper setup of anilox roller pressure against the plate
Uneven pressure across the width of the roller
Solution:
Use pressure gauges to ensure consistent pressure
Implement proper anilox roller setup procedures
Regular calibration of pressure settings
4. Substrate Tension Issues
How it happens:
Inconsistent tension throughout the printing process
Improper tension control system settings
Solution:
Install and maintain proper web tension control systems
Regularly calibrate tension sensors
Adjust tension settings for different substrate types
5. Plate Cylinder Eccentricity
How it happens:
Manufacturing defects in cylinders
Wear and tear over time
Improper handling or storage of cylinders
Solution:
Regular inspection of plate cylinders for concentricity
Use precision-manufactured cylinders
Proper storage and handling procedures for cylinders
6. Inconsistent Ink Viscosity
How it happens:
Temperature fluctuations in the pressroom
Improper ink mixing or preparation
Evaporation of solvents during long print runs
Solution:
Use automated ink viscosity control systems
Implement proper ink preparation and storage procedures
Monitor and adjust ink viscosity throughout the print run
7. Temperature Fluctuations
How it happens:
Inadequate climate control in the pressroom
Heat generated by the printing process
Seasonal changes affecting equipment and materials
Solution:
Install and maintain proper climate control systems
Monitor temperature throughout the printing process
Adjust equipment settings to compensate for temperature changes
8. Worn or Misaligned Bearings
How it happens:
Normal wear and tear over time
Improper lubrication
Misalignment during installation or maintenance
Solution:
Implement regular bearing inspection and maintenance schedule
Use proper lubrication techniques and schedules
Ensure precise alignment during bearing installation and replacement
9. Improper Impression Settings
How it happens:
Incorrect setup of impression pressure between plate and substrate
Improper setup or calibration of web guiding system
Unsuitable web guide system for the substrate being used
Solution:
Regular inspection and maintenance of web guiding systems
Proper calibration and setup for each job
Use appropriate web guiding technology for different substrates
By addressing these common causes of print misregistration, flexographic printers can significantly improve print quality and reduce waste. Regular maintenance, proper training, and investment in quality equipment are key to minimizing these issues.
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CI Flexo Printing Machine (Web Width:800-1400mm)
Product Description:
Central impression flexographic printing machine meet the requirements of the most demanding package printing applications.This type of press offers a high print quality and registration accuracy. It can print on PE, PP, OPP, PET, Paper etc.
Conclusion
Understanding and managing print registration is a critical aspect of flexographic printing. It requires a combination of proper equipment maintenance, skilled operation, and ongoing quality control. By addressing the various factors that contribute to misregistration, printers can improve quality, reduce waste, and enhance overall efficiency in their flexographic printing processes.
For expert guidance and technical support on your printing machine project, contact Oyang. Our experienced engineers will help you identify the problem, provide helpful suggestions to ensure optimal results. Partner with Oyang for success. We will take your production capabilities to the next level.
