Image Reading Roller Groups for Stable Card Conveyance
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Solution Overview
Problem
Conventional auto-document-feeder image reading apparatuses face challenges in stably conveying both sheet documents and card documents due to damage risks and increased skewing, especially when card documents are thicker and more rigid, which complicates downsizing the apparatus.
Innovation Solution
The apparatus employs a conveying unit with multiple pairs of rollers, where the center positions of different roller groups are aligned with their respective conveying areas, and a controlling member adjusts the biasing force on driven rollers to ensure stable conveyance of both sheet and card documents, preventing skewing and damage by using a combination of symmetric and asymmetric roller arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a bend section is introduced in the conveying path to achieve a compact structure, then the apparatus size is reduced, but card documents may get damaged or require larger driving force
Solution Approach 1:
The conveying unit is segmented into multiple roller pairs (first pair, second pair, third pair) arranged along the conveying path. Each roller pair independently conveys the medium, allowing the path to navigate around bends without forcing the entire medium through a single bent section, thus preventing damage while maintaining compact structure
Solution Approach 2:
Different roller pairs are positioned at different locations along the conveying path, with each pair providing localized conveyance support. The rollers are arranged such that card documents receive distributed support throughout the conveying path rather than being forced through a single bend point, reducing stress concentration and damage risk
2Stability of the object's composition
If multiple pairs of rollers are arranged symmetrically across the conveying path, then card documents can be conveyed stably, but the distance between rollers increases causing skewed documents to spin and skew more
Solution Approach 1:
The roller pairs are arranged asymmetrically along the conveying path rather than symmetrically across it. The first, second, and third roller pairs are positioned at different distances from the leading end in the conveying direction, creating an asymmetric configuration that reduces the lateral distance skewed documents must travel, preventing excessive spinning and skew while maintaining stable conveyance
Solution Approach 2:
The roller pairs are positioned to progressively correct skew early in the conveying process. By having rollers at different positions along the conveying direction, the system preliminarily addresses skew before it can accumulate, preventing documents from spinning excessively as they move through the apparatus
3Device complexity
If only one pair of rollers is used to convey card documents, then the structure is simplified, but card documents are not conveyed stably
Solution Approach 1:
The conveying functions of multiple roller pairs are merged to work together on card documents. The first, second, and third roller pairs are all engaged with card documents during conveyance, combining their forces to provide stable, multi-point support that prevents instability while maintaining a unified conveying action
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 configuration allows for stable and damage-free conveyance of both sheet and card documents, minimizing skewing and enabling the downsizing of the image reading apparatus while maintaining efficient operation.
Implementation Method 1
a conveying unit (3) that includes a plurality of pairs of rollers, each pair including a driving roller (7) and a driven roller (8) that is biased towards and rotates along with the driving roller (7), and that conveys the first medium (S1) and the second medium (S2) to the reading unit (4) while nipping the first medium (S1) and the second medium (S2) between the driving roller (7) and the driven roller (8)
Data Source
AI summary
An image reading apparatus includes pairs of rollers, each including a driving roller and a driven roller. The pairs of rollers are arranged along the rotation axis direction of the driving roller and constitute a first roller group and a second roller group for conveying a first medium and a second medium thicker than the first medium, respectively. The center of the first roller group is identical in the rotation axis direction to that of a first conveying area where the first medium is conveyed. The center of the second roller group is identical in the rotation axis direction to that of a second conveying area where the second medium is conveyed. At least one pair of rollers in the second roller group is arranged outside the first roller group within the first conveying area.