Document Reading Apparatus Velocity Control for Slack Stability
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Solution Overview
Problem
Conventional document reading apparatuses fail to set an appropriate amount of slack in documents based on their length and grammage, leading to unstable conveying velocities and fluctuations in slack formation, particularly due to slippage issues with thick documents.
Innovation Solution
A document reading apparatus with a determination unit to assess document length and grammage, and a control unit that adjusts the relative conveying velocities between the resist and read convey units using specific conveying velocity ratios to maintain consistent slack formation, optimizing the conveying process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed conveying velocity ratio is used between resist roller and read roller, then the device structure is simple, but the slack formation becomes unstable for documents of different lengths and grammages
Solution Approach 1:
The patent applies dynamics by making the conveying velocity ratio between the resist roller and read roller variable rather than fixed. The control unit dynamically adjusts the velocity ratio based on document characteristics (length and grammage) detected by the determination unit. This allows the system to adapt to different document types, ensuring stable slack formation while maintaining reasonable structural complexity through automated control.
2Productivity
If the resist roller conveys thick documents, then document processing is achieved, but slippage occurs causing unstable conveying velocity
Solution Approach 1:
The patent applies parameter changes by adjusting the conveying velocity of the resist roller based on the grammage (thickness) of the document. When thick documents are detected, the determination unit identifies the increased grammage, and the control unit modifies the velocity parameters to prevent slippage. This dynamic parameter adjustment ensures both productive document processing and stable conveying velocity for thick documents.
3Ease of operation
If conventional fixed velocity setting is used, then device operation is simple, but slack amount cannot be appropriately set for different document lengths
Solution Approach 1:
The patent applies self-service by enabling the system to automatically determine document characteristics and adjust conveying velocities without user intervention. The determination unit autonomously measures document length and grammage, and the control unit automatically calculates and applies the appropriate velocity ratio. This maintains ease of operation while achieving high adaptability to different document lengths and types.
Data Source
AI summary
A sheet-through document reading apparatus including: a document tray for containing a plurality of documents; a determination unit that determines a length of a document on the document tray; a feed unit that separates and feeds a document on the document tray; a resist convey unit that performs consistency processing on the document fed by the feed unit; a first drive unit that rotationally drives the resist convey unit; a read convey unit that feeds the document subjected to consistency processing by the resist convey unit; a second drive unit that rotationally drives the read convey unit; a reading unit that reads, at a fixed reading position, the document conveyed by the read convey unit; and a control unit for changing a relative conveying velocity between the resist convey unit and the read convey unit on the basis of a result of the determination by the determination unit.