Cardboard Splice Detection with Ultrasonic Thickness and Mark Verification

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Solution Overview

Problem

Existing cardboard sheet-manufacturing processes face inaccuracies in detecting paper splice parts due to variations in position calculation, leading to increased defective sheets and bridge stagnation quantity errors, especially when using metal sensors that fail to detect splice parts during sheet meandering.

Innovation Solution

A paper splice part detection device that utilizes a sheet paper splice detection unit, marking device, and mark detection device to identify splice parts based on sheet shape, without relying on metal plates, by using ultrasonic sensors or laser displacement sensors to detect thickness variations and assign marks for accurate detection and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal sensors are used to detect paper splice parts, then detection is possible, but detection accuracy deteriorates when sheets meander

Engineering Contradiction:
Improvedetection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces metal sensors (mechanical/electromagnetic detection system) with ultrasonic sensors that detect thickness variations through acoustic waves. This substitution eliminates the meandering problem because ultrasonic sensors measure local thickness at the detection point rather than relying on fixed positional relationships, thereby maintaining detection accuracy even when sheets move or wave during transfer.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces thickness variation as an intermediary characteristic for detection. Instead of directly detecting the paper splice part through metal sensors, the system uses ultrasonic sensors to detect changes in sheet thickness caused by the splice, which creates a measurable physical property that remains consistent even when the sheet position varies.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If position calculation is used to identify splice parts, then detection is achieved, but manufacturing precision deteriorates due to position calculation variations

Engineering Contradiction:
Improvedetection efficiencyVSAvoidsplice part detection accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces position calculation methods with direct physical measurement using ultrasonic sensors. Instead of calculating splice part positions based on sheet movement data and timing, the system directly measures thickness variations at the detection point, eliminating errors introduced by position calculation variations and sheet meandering.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The ultrasonic sensor system performs self-adjustment by automatically adapting to sheet position variations. The sensor detects thickness changes locally at its fixed position,无需 relying on external position calculation systems, thereby eliminating the need for complex position tracking and calculation mechanisms.

Inventive Principle:
Principle #25Self-service

3Reliability

If many sheets are removed as defective based on position accuracy variations, then detection reliability improves, but productivity deteriorates

Engineering Contradiction:
Improvesplice part detection reliabilityVSAvoidsheet production efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces position-based detection with thickness-based ultrasonic detection, which provides accurate splice part identification without the position accuracy variations that lead to excessive defective sheet removal. This substitution maintains high detection reliability while significantly reducing the number of false positives and improving overall production efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Improves accuracy in detecting paper splice parts, reducing defective sheets and ensuring precise measurement of bridge stagnation quantity, thereby enhancing the quality and efficiency of cardboard sheet production.

Implementation Method 1

using ultrasonic sensors or laser displacement sensors to detect thickness variations

Methodology Applied
Scientific EffectUltrasonic detection: Ultrasound

Implementation Method 2

using ultrasonic sensors or laser displacement sensors to detect thickness variations

Methodology Applied
Scientific EffectLaser displacement detection: LIDAR

Data Source

PatentEP4245514B1Device for detecting paper splice part of cardboard sheet, and device for producing cardboard sheet
Publication Date: 2025.12.03 MITSUBISHI HEAVY IND MACHINERY SYST LTD
  • EP4245514B1 patent drawingFigure 1
  • EP4245514B1 patent drawingFigure 2
  • EP4245514B1 patent drawingFigure 3

AI summary

In a device for detecting a paper splice part of a cardboard sheet and a device for producing a cardboard sheet, the device for detecting a paper splice part of a cardboard sheet, which detects a sheet paper splice part of a cardboard sheet that has a first sheet, a corrugated second sheet, and a third sheet bonded together, comprises: a sheet paper splice detection unit that detects the sheet paper splice part on the basis of the shape of the sheet and that is placed between a position at which sheets are spliced and a position at which the sheets are bonded in a sheet carrying direction; a marking device that marks the sheet paper splice part on the downstream side of the sheet paper splice detection unit in the sheet carrying direction; and a mark detection device that detects the mark on the downstream side of the marking device in the sheet carrying direction.