Transparent Sheet Member Scratch Prevention in Image Readers
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Solution Overview
Problem
In image reading apparatuses, transparent reading sheets are prone to scratching during document feeding, leading to reduced reading light quality and increased costs due to hard coatings, which cause image distortions and reflectivity issues.
Innovation Solution
An image reading apparatus design featuring a transparent sheet member with a first sheet portion covering the document conveyance path and a second sheet portion in contact with the document discharge guide, preventing direct contact with the document and reducing scratching, along with an anti-reflection treatment to minimize light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hard coating is applied to the transparent reading sheet, then the scratch resistance is improved, but the manufacturing cost increases
Solution Approach 1:
The patent removes the transparent reading sheet entirely from the document feeding path. Instead of protecting the sheet through hard coating, the invention extracts the sheet from the system and uses a document guide member to directly guide documents to the reading position, eliminating the need for scratch-resistant coatings and reducing manufacturing costs
Solution Approach 2:
The patent replaces the expensive transparent reading sheet with a simpler, less costly document guide member that does not require protective coatings. The guide member serves its function without needing the durability and optical properties of a transparent sheet, allowing for a more economical solution
2Ease of operation
If transparent reading sheet is used, then the document conveyance is enabled, but the sheet is scratched leading to reading quality degradation
Solution Approach 1:
The patent extracts the transparent reading sheet from the document conveyance system and replaces it with a document guide member. This eliminates the scratching problem that degrades reading quality while maintaining the document conveyance function through direct mechanical guidance
Solution Approach 2:
The patent introduces a document guide member as an intermediary component between the document and the reading unit. This guide member directly contacts and guides the document without requiring a transparent sheet, thereby maintaining reading quality while enabling document conveyance
3Ease of operation
If transparent reading sheet is placed on contact glass, then the document feeding is facilitated, but the leading end of document collides with document discharge guide
Solution Approach 1:
The patent removes the transparent reading sheet that caused the collision problem and replaces it with a document guide member positioned to guide documents smoothly to the reading position without interference from discharge guide structures
Solution Approach 2:
The document guide member is designed to self-align and guide documents through the feeding path without requiring additional transparent sheets or complex mechanisms, preventing collisions through its inherent geometric design
Data Source
AI summary
An image reading apparatus includes a first housing, a second housing, a document conveyance path, a plate-like transparent member, a reader, a guide member, a transparent sheet member and a pressing member. The guide member is arranged on the transparent member at a side downstream of the first position in a conveying direction of the document and guides the document to a downstream side in the conveying direction. The transparent sheet member includes a first sheet portion which is arranged on the transparent member to cover the first position and a second sheet portion which is held in contact with the guide member and with which the document being conveyed along the document conveyance path comes into contact. The pressing member presses a side of the first sheet portion upstream of the first position in the conveying direction against the transparent member.