Absorbent Article Sheet Image Positioning Control
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Solution Overview
Problem
Winding a sheet in a roll body configuration at uniform tension is difficult, leading to variations in image pitch and potential shifts in pattern position due to fluctuations in sheet tension, especially when there is a long distance between detection and bonding positions in absorbent article manufacturing.
Innovation Solution
A method involving the superposition of a continuous first sheet and a second sheet at a merge position, with controlled feed speed and position adjustment based on image detection to maintain stable image positioning and feed speed synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the detection position is placed far from the bonding position to allow sufficient time for image detection and processing, then the control system has adequate response time, but the sheet tension fluctuations cause pattern position shifts during the long conveyance distance
Solution Approach 1:
A pattern position adjustment means is introduced as an intermediary device between the detection position and the bonding position. This adjustment means includes a pair of rollers that can independently adjust the path length of the continuous member, allowing fine-tuning of the pattern position to compensate for tension fluctuations during conveyance, thereby maintaining positioning accuracy despite the long distance.
Solution Approach 2:
The system implements a feedback control mechanism where the detected image position is continuously monitored, and the pattern position adjustment means responds by modifying the path length based on the detected deviations. This closed-loop feedback ensures that pattern position accuracy is maintained at the bonding position despite variations in sheet tension during the long conveyance distance.
2Manufacturing precision
If an adjustment means is disposed near the bonding position to minimize pattern position shifts, then pattern positioning accuracy is improved, but the adjustment means must perform both feed speed adjustment and pattern position adjustment, causing hunting instability
Solution Approach 1:
The adjustment functions are segmented into two independent components: a feed speed adjustment means that controls the overall feed rate of the continuous member, and a pattern position adjustment means that specifically adjusts the pattern position by modifying the path length. This segmentation allows each component to perform its function independently without interfering with the other, eliminating the hunting instability that occurs when both adjustments are combined in a single means.
3Manufacturing precision
If the path length from feed position to merge position is kept long to allow sufficient adjustment range, then pattern position can be precisely adjusted, but the feed speed control becomes less responsive to tension changes
Solution Approach 1:
The pattern position adjustment means acts as an intermediary that decouples the path length modification from the feed speed control. By introducing this intermediate adjustment mechanism, the system can extend the effective adjustment range for pattern positioning without compromising the responsiveness of the feed speed control, as the path length changes are made locally at the adjustment means rather than through overall feed speed modifications.
Data Source
Figure 1A~1B
Figure 2
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AI summary
This disclosure is a method for manufacturing a sheet-shaped member by superimposing a continuous first sheet and a continuous second sheet at a merge position to configure the sheet-shaped member having contiguously arranged absorbent articles. In the method, supplying the first sheet having extensibility and formed periodically with an image from a roll body. In the method, feeding the first sheet toward the merge position by controlling a feed speed of the first sheet such that an amount of the first sheet equivalent to a single unit of the absorbent article is fed every time an amount of the sheet-shaped member equivalent to a single unit of the absorbent article is conveyed. In the method, adjusting a position of the image with respect to the absorbent article by detecting the image on the first sheet, and changing a path length from a feed position where the feed speed of the first sheet is controlled to the merge position based on a result of detecting the image.