Gloss Measurement Apparatus for Moving Sheets

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Solution Overview

Problem

Current methods for measuring small-scale gloss on moving surfaces, such as paper or cardboard, face inaccuracies due to the surface movement during exposure and the complexity of measurement configurations involving cameras and stroboscopic flashes, leading to a need for improved accuracy and simplicity in gloss measurement.

Innovation Solution

An apparatus and method utilizing a small light spot detection system where a narrow light source and detector configuration allow for precise measurement of gloss on moving sheets by integrating light intensity over a short time window, achieving high spatial resolution through controlled spot size and detection time, enabling accurate measurement of small-scale gloss variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a camera with stroboscopic flash is used to capture moving surface, then gloss measurement is possible, but measurement accuracy deteriorates due to surface movement during exposure

Engineering Contradiction:
Improvegloss measurement accuracyVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses periodic stroboscopic illumination synchronized with the moving surface to capture gloss information at specific intervals, allowing measurement of moving surfaces while maintaining accuracy through timed periodic detection rather than continuous exposure

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If a camera with detector matrix and stroboscopic flash is used, then gloss measurement capability is achieved, but device complexity increases

Engineering Contradiction:
Improvegloss measurement capabilityVSAvoidmeasurement configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and focuses measurement on specific small areas of the surface using targeted illumination and selective detection, rather than requiring complex matrix detectors to capture entire surfaces, thereby simplifying the overall device configuration while maintaining measurement capability

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If a small measured area is used for micro gloss measurement, then spatial resolution is improved, but measurement reliability deteriorates due to surface movement

Engineering Contradiction:
Improvespatial resolutionVSAvoidmeasurement reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

By using periodic stroboscopic illumination synchronized with surface movement, the system can capture reliable gloss data from small specific areas at defined time intervals, simultaneously achieving high spatial resolution and measurement reliability through temporal synchronization

Inventive Principle:
Principle #19Periodic 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 allows for precise measurement of small-scale gloss variations, enhancing process control by providing accurate and reliable data on surface texture and gloss, addressing the limitations of existing methods by improving spatial resolution and measurement accuracy.

Implementation Method 1

Surface gloss is conventionally measured as a specular reflection of visible light from a relatively large area

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2914954B1Method and apparatus for measuring gloss
Publication Date: 2020.02.19 VALMET AUTOMATION OY
  • EP2914954B1 patent drawingFigure 1A~1C
  • EP2914954B1 patent drawingFigure 2~5
  • EP2914954B1 patent drawingFigure 6~7

AI summary

An apparatus of measuring a small scale property of a sheet, the apparatus comprises: a first light source for illuminating the sheet moving with respect to the illumination; a detector for forming a total intensity of reflection of the light illuminating the moving sheet by each detection; a detected dimension of the reflection on the sheet in the direction of the movement being limited the same as or shorter than a lowest acceptable spatial resolution of the measurement;a duration of each detection being equal to or shorter than the lowest acceptable spatial resolution divided by a speed of the moving sheet; and a processing unit for forming information about a small scale variation of gloss of the sheet on the basis of the detections by the detector.