Target Sheet Detection Without Register Marks
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Solution Overview
Problem
Existing methods for detecting sticking defects in target sheets during the manufacture of connectable disposable wear articles, such as diapers, require register marks that restrict appearance design and increase printing costs.
Innovation Solution
A method utilizing high whiteness levels of 80% or more on the target sheet's corner portions to enhance light transmittance differences, allowing for detection without register marks through transmitted light detection using an image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a register mark is printed on the target sheet for detection, then the shape and dimensions can be detected, but the appearance design is restricted and printing cost increases
Solution Approach 1:
The target sheet itself serves as the detection marker through its inherent corner portions with high whiteness (80% or more). The sheet's own structural features (corners) are utilized for detection purposes, eliminating the need for external register marks. This allows the sheet to detect itself without additional printing or markers, preserving appearance design freedom while maintaining detection accuracy.
2Measurement precision
If a register mark is printed on the target sheet for detection, then the shape and dimensions can be detected, but the printing cost increases due to ink consumption
Solution Approach 1:
The target sheet's corner portions with high whiteness serve as self-contained detection markers. By utilizing the sheet's inherent optical properties rather than printed markers, the invention eliminates ink consumption entirely for detection purposes, reducing material loss while maintaining detection accuracy.
Solution Approach 2:
The invention uses the disposable nature of the target sheet itself as the detection mechanism. Rather than adding permanent or reusable detection markers, the sheet's own structural features are exploited, making the detection system as disposable and cost-effective as the sheet itself without requiring additional expensive printing materials.
3Measurement precision
If the whiteness of corner portions is increased to 80% or more for detection, then light transmittance difference increases and detection accuracy improves, but the material composition becomes more restricted
Solution Approach 1:
The invention specifies a parameter threshold (whiteness of 80% or more) for the corner portions of the target sheet. By setting this quantitative parameter, the invention transforms a qualitative material selection problem into a measurable specification, allowing manufacturers to choose from various materials that meet this whiteness criterion while ensuring sufficient light transmittance difference for accurate detection.
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 method enables accurate detection of target sheets and sticking defects like curling corners, misaligned sticking positions, and cutting dimension deviations without the need for register marks, improving detection accuracy and reducing costs.
Implementation Method 1
one of front and back surfaces thereof (for example, opposite side from the target sheet) is irradiated with light, transmitted light transmitted to a surface on the opposite side is detected by a photodetector such as an image sensor
Data Source
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AI summary
Position detection of a target sheet is facilitated without requiring a register mark. The above-mentioned problem is solved by a connectable disposable wear article having a crotch portion M including a center in a front-back direction LD, a ventral side part F extending forward from the center in the front-back direction LD, and a dorsal side part B extending backward from the center in the front-back direction LD, connecting portions 83 to be detachably connected to an outer surface of the ventral side part F being provided on both side portions of the dorsal side part B, a target sheet 20 to which the connecting portions 83 are connected being provided on the outer surface of the ventral side part F, in which a whiteness of all corner portions 21 on at least one of an inner surface and an outer surface of the target sheet 20 is 80% or more.