Illumination Unit for Sheet Processing Quality Control

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Solution Overview

Problem

Existing quality control stations for sheet element processing machines face challenges in maintaining constant illumination intensity across varying sheet element thicknesses, such as thin paper and thick cardboard, which affects image capture quality.

Innovation Solution

The quality control station incorporates an illumination unit with a light emitter, two reflectors, and a diffuser, configuring light to be emitted in three portions: directly to the viewing area and reflected by the reflectors, ensuring a constant illumination intensity varying by no more than 5% over a 12mm vertical zone, regardless of sheet element thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the illumination unit uses only reflectors to direct light to the viewing area, then the illumination intensity is constant for a specific sheet element thickness, but the illumination intensity varies significantly when sheet element thickness changes

Engineering Contradiction:
Improveillumination intensityVSAvoidadaptability to different sheet element thicknesses
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The illumination unit divides the light emission into three distinct portions: direct light from the emitter, light reflected by a first reflector, and light reflected by a second reflector. This segmentation allows each portion to contribute differently to the overall illumination, enabling the system to maintain constant illumination intensity across varying sheet element thicknesses without requiring adjustments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the viewing area receive light with different characteristics: the direct light portion provides intense illumination for areas closer to the emitter, while the reflected light portions provide more diffuse illumination for areas at different vertical positions. This local quality differentiation ensures uniform illumination across the entire viewing area regardless of sheet element thickness.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the quality control station is designed for a specific viewing area height, then the illumination intensity is optimized for that height, but the station cannot accommodate sheet elements of different thicknesses

Engineering Contradiction:
Improveillumination intensity uniformityVSAvoidaccommodation of different sheet element thicknesses
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The illumination unit is designed to serve multiple functions simultaneously: it provides constant illumination intensity for thin sheet elements (paper) and thick sheet elements (cardboard) without requiring reconfiguration. The combination of direct and reflected light portions creates a universal illumination system that adapts to various sheet element thicknesses within the designed viewing area zone.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If the viewing area zone height is increased to accommodate thick sheet elements, then the adaptability improves, but the illumination intensity becomes non-uniform across the viewing area

Engineering Contradiction:
Improveviewing area zone heightVSAvoidillumination intensity uniformity
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The reflectors act as intermediaries that redirect light from the emitter to different portions of the viewing area. The first reflector directs light to illuminate areas at lower vertical positions, while the second reflector directs light to illuminate areas at higher vertical positions. This intermediary action ensures that even when the viewing area zone height is increased to accommodate thick sheet elements, the illumination intensity remains uniform across the entire expanded zone.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration provides consistent and homogeneous illumination across a wide zone, eliminating the need for adjustments based on sheet element thickness, ensuring reliable image capture and quality control for both thin and thick materials.

Implementation Method 1

a first portion of the light is emitted by the light emitter towards the first reflector and is reflected towards a viewing area of the processing machine and a second portion of the light is emitted by the light emitter towards the second reflector and is reflected towards the viewing area

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3465170B1Quality control station for a sheet element processing machine having illumination unit
Publication Date: 2024.01.24 BOBST MEX SA
  • EP3465170B1 patent drawingFigure 1~2
  • EP3465170B1 patent drawingFigure 3~4
  • EP3465170B1 patent drawingFigure 5~6

AI summary

The invention relates to a quality control station (2) for a sheet element processing machine, having at least one camera (6) arranged for capturing images of sheet elements (4) transported through the quality control station (2), and further having an illumination unit (5) with at least one light emitter (16) and two reflectors (12, 14), the illumination unit (5) being adapted for directing light onto a viewing area of the camera (6) such that the illumination intensity is constant despite changing media thickness. The invention further relates to an illumination unit for such quality control station.