Document Reading Device Skew Detection at the Feed-Roller Nip
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image reading devices struggle with skew errors when feeding documents with varying lengths, particularly long documents, which can cause subsequent documents to skew or overlap due to displacement of their side edges into the nip region during feeding.
Innovation Solution
A reading device with a control section that performs skew judgment based on the image of the tip end region of a preceding document, calculating tilt angles and distances to determine if the document edges are displaced into the nip region, allowing for early detection and prevention of transport errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tilt angle threshold is reduced for long documents to detect skew errors earlier, then skew error detection capability is improved, but false detection increases when subsequent documents are present
Solution Approach 1:
The control section performs skew judgment based on the image of the preceding document before the subsequent document is fully fed into the reading section. By detecting the tilt angle of the preceding document's side edge portion and judging whether it displaces into the nip region, the system performs preliminary detection to prevent false skew error detection when subsequent documents are present, thereby improving reliability while maintaining detection capability
Solution Approach 2:
The system uses the image data from the preceding document to provide feedback for skew judgment. By analyzing the position of the side edge portion in the scanned image and comparing it with the nip region boundaries, the control section receives feedback on document alignment and adjusts its determination of whether a skew error has occurred, reducing false detections
2Productivity
If the feed roller feeds documents quickly to improve productivity, then feeding speed is improved, but transport error occurs when side edge portions displace into the nip region
Solution Approach 1:
The control section performs skew judgment based on the preceding document's image before the document is fully transported through the feeding mechanism. By detecting the tilt angle and side edge position early in the feeding process, the system can identify potential transport errors before they affect subsequent documents, allowing for corrective action while maintaining high feeding speed
Solution Approach 2:
The image data of the preceding document serves as an intermediary indicator of potential transport errors. Instead of directly monitoring the physical position of documents during high-speed feeding, the system uses the scanned image to infer whether side edge portions have displaced into the nip region, enabling error detection without slowing down the feeding process
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A control section of a reading device performs skew judgment based on an image of a preceding document scanned by the reading section to determine whether the side edge portion of the preceding document is displaced into a nip region sandwiched between a feed roller and a separation section. When it is determined that the side edge portion of the preceding document is displaced into the nip region and also the detection section, which detects a document placed on the placement section, detects a subsequent document, the control section determines a transport error.