Register Mark Positioning for Packaging Web Printing

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Solution Overview

Problem

Current digital printing methods for packaging materials face challenges in achieving accurate printing of designs on packaging materials, particularly for roll-fed packaging machines, which can lead to inaccuracies in the placement of printing décor on packages.

Innovation Solution

A method and printing module that utilize a combination of first and second sensors with different pixel counts to identify and determine the positions of register marks on packaging material, allowing for precise adjustment and printing of the web in relation to printer bars, ensuring accurate placement and printing of designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If digital printing is used for printing packaging material, then flexibility and cost-effectiveness for smaller batches are improved, but printing accuracy deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidprinting accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent employs a feedback mechanism where sensors detect the position of register marks on the packaging material web, and this information is used to adjust the printing process in real-time. The system continuously monitors the actual position of the web and compares it with the desired position, making corrections to maintain accurate printing despite variations in web tension, speed, or positioning.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses preliminary action by printing or marking register marks on the packaging material before the actual printing process. These register marks serve as reference points that are detected by sensors, allowing the system to pre-determine the correct positioning and alignment before the main printing operation begins, ensuring accurate placement of printing décor.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If a single sensor is used to identify register marks, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvesensor configurationVSAvoidregister mark position accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the measurement task into segments by using multiple sensors positioned at different locations along the packaging material web. Each sensor is responsible for detecting register marks in its specific zone, allowing for more precise local measurements while maintaining manageable system complexity through modular sensor placement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enhances measurement precision by adding a spatial dimension to the detection system. Instead of relying on a single sensor, multiple sensors are positioned at different longitudinal positions along the web, creating a multi-dimensional measurement approach that captures position information from multiple points, thereby improving overall measurement accuracy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3670408B1A method for printing a web of packaging material and an apparatus thereof
Publication Date: 2023.03.29 TETRA LAVAL HOLDINGS & FINANCE SA
  • EP3670408B1 patent drawingFigure 1
  • EP3670408B1 patent drawingFigure 2~3
  • EP3670408B1 patent drawingFigure 4

AI summary

A method (500) for printing a web (102) of packaging material for packages (112) holding liquid food products is provided. The web (102) comprises a number of blanks placed after one another, wherein each blank corresponds to one package, wherein each of the blanks comprises a first area (302, 402) that is pre-printed and a second area (304, 404) to be printed. The method comprises receiving (502) the web (102) of packaging material, identifying (504) a first register mark (306, 406) using a first sensor (204), determining (506) a first register mark position based on the first register mark (306, 406), determining (508) a second register mark position area based on the first register mark position, identifying (510) a second register mark (308, 408) within the second register mark position area using a second sensor (208) and determining a second register mark position for the second register mark, determining (512) a second area position of the second area based on the second register mark position, adjusting (514) the web in relation to printer bars (210) in accordance with the second area position, determining (512) a second area position of the second area (304, 404) based on the second register mark position, and printing (516) the second area (304, 404) by using the printer bars (210).