Document Guide Step Member Elastic Deformation for Image Size Consistency
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Solution Overview
Problem
Conventional image reading apparatuses experience degradation in image quality due to foreign matter transfer onto the transmitting glass, leading to sudden changes in image size at the trailing end, which are conspicuous and difficult to prevent with existing configurations.
Innovation Solution
An image reading apparatus with a step member positioned upstream of the reading position, featuring a document guiding surface at a prescribed distance from the transmitting glass and a protrusion that elastically deforms to guide the trailing end of the document closer to the glass, forming an inclined surface that gradually increases the image size, thus minimizing conspicuous size changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the document is conveyed with a prescribed distance from the transmitting glass, then foreign matter transfer is prevented, but the trailing end of the document forcefully moves to the glass causing sudden image size increase
Solution Approach 1:
The downstream end of the step member is made elastically deformable, allowing it to dynamically adjust its position. When the document's trailing end contacts this elastic portion, it gradually moves closer to the transmitting glass rather than forcefully jumping, thus preventing sudden image size changes while maintaining the gap during normal conveyance
Solution Approach 2:
The elastic deformability of the step member's downstream end changes the parameter of document-to-glass distance from fixed to variable. This allows the distance to gradually decrease at the trailing end through elastic deformation, transforming the abrupt distance change into a gradual transition that prevents conspicuous image size changes
2Manufacturing precision
If the end of the sheet member is made into an inclined surface to gradually guide the document, then image size change is reduced, but the step member becomes complex and difficult to manufacture
Solution Approach 1:
The step member's downstream end is designed as a thin, elastic film or shell structure that can deform under the document's weight. This elastic portion naturally forms a gradual inclination when deformed, achieving the same effect as a manufactured inclined surface but with simpler fabrication through material selection rather than complex shaping
Solution Approach 2:
Instead of changing the geometric shape of the step member into a complex inclined surface, the invention changes the material parameter to introduce elastic deformability. This allows the structure to naturally form the desired gradual inclination through deformation, simplifying manufacturing while achieving the same functional result
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 sudden changes in image size at the trailing end, maintaining image quality by allowing the document to gradually move closer to the transmitting glass, reducing the visibility of size changes and ensuring consistent image reproduction.
Implementation Method 1
the trailing end of the document forcefully moves to the side of the transmitting glass due to the stiffness of the document... The step member is provided with a protrusion protruding downstream in the conveying direction of the document to form space between the transmitting glass and a downstream part of the step member
Data Source
AI summary
An image reading apparatus includes: a transmitting glass; and a step member that is located upstream of a reading position, at which an image of a conveyed document is read by a reading unit via a transmitting glass, in a conveying direction of the document, and has a document guiding surface at a position away from a surface of a transmitting glass by a prescribed distance and forms a step between the document guiding surface and the transmitting glass. The step member is provided with a protrusion protruding downstream in the conveying direction of the document to form space between the transmitting glass and a downstream part of the step member in the conveying direction of the document.