Print Repeat Length Variability Correction in Extensible Web Printing

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Solution Overview

Problem

Printing on extensible materials like polymer films faces challenges due to varying tensions during winding and relaxation, leading to significant print repeat length variability, which causes distortion and misalignment in printed patterns when the material is unwound and used in products.

Innovation Solution

A method that involves determining an adjusted print repeat length profile to compensate for these effects, allowing the print repeat length to vary along the web during printing, using a gearless flexographic printing press with feedback control to maintain consistent print repeat length, reducing variability to less than 0.2%.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a constant print repeat length is used during printing, then the printing process is simple and fast, but the print repeat length variability increases significantly after winding and aging

Engineering Contradiction:

Improveprinting speedVSAvoidprint repeat length consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary measurement of the actual print repeat length during printing, then uses this information to make real-time adjustments to the printing parameters. This preliminary action allows the system to compensate for variations before they accumulate, maintaining precision without sacrificing productivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback control system where the actual print repeat length is continuously measured and compared against target values. The system then adjusts printing parameters based on this feedback to maintain consistent print repeat length throughout the web, even as conditions change during the printing process.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If the print repeat length is adjusted to compensate for winding and aging effects, then the final print repeat length consistency improves, but the printing process complexity increases

Engineering Contradiction:

Improveprint repeat length consistencyVSAvoidprinting process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The printing system performs self-measurement of its own output using integrated sensors and measurement devices. The system automatically detects print repeat length variations and adjusts its own parameters without external intervention, reducing the need for complex external control systems while maintaining high precision.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically changes printing parameters such as print repeat length, printing speed, and tension based on real-time measurements and predictions of winding and aging effects. This automated parameter adjustment achieves high precision without requiring complex manual intervention or overly complicated equipment.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If high printing speed is maintained, then productivity is high, but the ability to measure and control print repeat length variability decreases

Engineering Contradiction:

Improveprinting speedVSAvoidprint repeat length measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The measurement and control system operates continuously throughout the printing process without interrupting the printing speed. Sensors and measurement devices are integrated into the printing line to measure print repeat length in real-time as the web passes through, maintaining both high productivity and measurement accuracy simultaneously.

Inventive Principle:

Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach ensures that the printed material maintains a consistent print repeat length even after aging, reducing distortion and misalignment issues, enabling high-quality graphics and text on products like packaging films and disposable hygiene items.

Implementation Method 1

The measuring step may be performed automatically by a repeat length measurement device, such as an optical device (e.g., a camera capable of measuring images)

Methodology Applied

Scientific EffectOptical measurement: Reflection

Data Source

PatentUS7584699B2Method for correcting print repeat length variability in printed extensible materials and product

Publication Date: 2009.09.08 BERRY FILM PRODUCTS CO INC

AI summary

A method of printing a repeating pattern on a web of an extensible material by providing a web of an extensible material, determining an adjusted print repeat length profile for a repeating pattern to be printed on the web of material; and printing a repeating pattern on a surface of the extensible material, the repeating pattern comprising printed indicia which is repeated along the length of the web, such that the print repeat length of the printed indicia varies along the length of the web in accordance with the adjusted print repeat length profile.