Base Material Edge Displacement Detection Using Upstream Downstream Signal Matching
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Solution Overview
Problem
Conventional image recording apparatuses face challenges in accurately detecting displacement of long band-like base materials during transport, leading to misregistration of single-color images due to variations in transport speed and elongation, which is difficult to correct without relying on register marks that occupy valuable print space.
Innovation Solution
A base material processing apparatus with a transport mechanism, upstream and downstream detectors that successively or intermittently detect the edge position of the base material, and a displacement calculation part that identifies highly matched data sections using signal comparisons in specific frequency bands to calculate displacement and speed differences, allowing for accurate detection without relying on surface images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference images (register marks) are formed on the surface of the printing paper to detect displacement, then the position detection accuracy is improved, but the available space for recording the intended print image is reduced
Solution Approach 1:
The invention extracts the detection function from the surface of the printing paper by using edge detection at upstream and downstream positions. Instead of placing register marks on the print surface, the system detects the edge of the base material and calculates displacement based on the temporal change in edge position, thereby eliminating the need for surface markings and preserving the entire print area.
Solution Approach 2:
The invention introduces an intermediary calculation method that uses the relationship between upstream and downstream edge detection data to determine displacement. By calculating the temporal derivative of edge position or comparing detection results from two positions, the system derives displacement information without requiring physical markers on the base material.
2Device complexity
If conventional edge detection methods are used to detect base material displacement, then the detection system is simple, but the detection accuracy is insufficient due to inability to successively detect displacement
Solution Approach 1:
The invention segments the detection system into two independent edge detection units positioned at upstream and downstream locations. Each unit independently detects edge position, and the control unit processes both signals to calculate displacement. This segmentation allows continuous monitoring of base material movement while maintaining relatively simple individual detector designs.
Solution Approach 2:
The system implements feedback by continuously comparing upstream and downstream edge detection results and using this information to calculate real-time displacement. The control unit processes the temporal relationship between detection signals to determine movement amount, providing continuous feedback on base material position without requiring complex individual sensors.
3Device complexity
If the transport speed of the printing paper is not constant due to skids or elongation, then the transport mechanism is simple, but the image registration accuracy deteriorates
Solution Approach 1:
The invention replaces mechanical speed control mechanisms with an optical/electronic detection and calculation system. Instead of using complex variable speed drives or mechanical feedback mechanisms to maintain constant transport speed, the system uses upstream and downstream edge detectors to electronically measure actual transport speed variations and calculate displacement, substituting mechanical precision requirements with computational correction.
Data Source
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AI summary
A displacement amount calculation part (41) in a base material processing apparatus calculates the degree of matching between an upstream data section (D1) included in an upstream detection result (R1), which indicates a time-varying change in the position of an edge (91) of the base material in the width direction at an upstream detection position (Pa), and a downstream data section (D2) included in a downstream detection result (R2), which indicates a time-varying change in the position of the edge (91) of the base material in the width direction at a downstream detection position (Pb). This calculation uses the results of comparison between signals (RIM) in a predetermined frequency band extracted from the upstream detection result (R1) and signals (R2M) in the predetermined frequency band extracted from the downstream detection result (R2). Accordingly, a downstream data section (D2) that is highly matched with the upstream data section (D1) can be identified with high accuracy, and the amount of displacement of the base material in the transport direction can be detected with high accuracy on the basis of an identification result.