Pressing Portion Reduces Skew in Mixed-Size Document Feeding
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Solution Overview
Problem
Existing image reading apparatuses with automatic document feeders struggle to prevent skewing of documents with varying widths, as edge guides are ineffective when mixed-sized sheets are fed, leading to improper alignment and reading issues.
Innovation Solution
A medium feeding apparatus with a pressing portion, such as a roller, that applies friction upstream of the feed roller, adjustable in position and force, to stabilize documents of different sizes, combined with pivoting and sliding mechanisms to accommodate varying document heights and lengths, ensuring proper alignment and reducing skewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If edge guides are used to guide document edges, then skew is prevented or reduced for documents of the same size, but skew cannot be prevented when documents of different sizes are fed together
Solution Approach 1:
The pressing portion applies localized pressure at a specific position upstream of the feed roller to press the document onto the document placement portion. This localized action creates friction at the pressing position, which prevents skew regardless of the document's width size, thus resolving the contradiction between alignment precision and adaptability to different sizes.
2Manufacturing precision
If a pressing portion is added upstream of the feed roller, then skew is prevented for documents of different sizes, but device complexity increases
Solution Approach 1:
The pressing portion serves multiple functions: it presses documents of any size onto the document placement portion to prevent skew, and its position can be adjusted along the document placement portion to accommodate different document sizes. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity.
Solution Approach 2:
The pressing portion is designed to be movable along the document placement portion, allowing its position to be dynamically adjusted according to the size of the document being fed. This dynamic adjustment capability enables a single pressing portion to handle various document sizes effectively, avoiding the need for multiple fixed pressing portions and thus limiting complexity increase.
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
The solution effectively prevents or reduces skewing of documents with varying widths, ensuring accurate feeding and reading by applying adjustable friction and positional alignment, enhancing user operation and reducing the risk of document damage.
Implementation Method 1
at least one pressing portion that presses the medium placed on the medium placement portion onto the medium placement portion at a position upstream of the feed roller in a medium feeding direction
Data Source
AI summary
An image reading apparatus includes a reading unit and a medium feeding apparatus. The medium feeding apparatus includes: a medium placement portion on which a medium before being fed is placed; a feed roller that feeds the medium placed on the medium placement portion; and at least one pressing portion that presses the medium placed on the medium placement portion onto the medium placement portion at a position upstream of the feed roller in a medium feeding direction. Since the pressing portion presses the medium placed on the medium placement portion, friction occurs between sheets of the medium, thereby preventing or reducing a skew.