Drive Roller Stabilizes Document Speed in Image Scanning
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Solution Overview
Problem
Image reading devices with automatic document feed units experience unpredictable document delivery speed due to frictional contact between documents and scanning components, leading to inaccurate scanning.
Innovation Solution
Incorporating a drive roller on the white bar that rotates to maintain a constant document speed between the scanning glass and the white bar, with a guide film and rollers to stabilize document delivery, ensuring consistent scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a white bar is used to position the document against the scanning glass, then the document can be positioned correctly, but the document experiences frictional contact with both the white bar and scanning glass causing unexpected temporary changes in delivery speed
Solution Approach 1:
A drive roller is introduced as an intermediary component between the document and the scanning glass. The drive roller contacts the document to apply driving force, while being spaced apart from the scanning glass to avoid direct frictional contact with it. This intermediary mechanism allows controlled document delivery without the harmful frictional interaction between the document and scanning glass that causes speed variations.
Solution Approach 2:
The harmful frictional contact between the document and scanning glass is extracted/eliminated by introducing the drive roller. Instead of the document directly contacting both the white bar and scanning glass, the drive roller mediates the interaction, separating the positioning function (white bar) from the driving function (drive roller) to avoid conflicting frictional forces.
2Productivity
If the drive roller is placed close to the scanning glass to effectively drive the document, then document delivery is improved, but the drive roller may interfere with the scanning process
Solution Approach 1:
The drive roller is designed with specific spatial characteristics: it contacts the document at a localized point to apply driving force, while maintaining a controlled gap (0.1mm to 1.0mm) from the scanning glass. This local quality design allows the drive roller to effectively drive the document without interfering with the scanning area, balancing delivery efficiency with scanning reliability.
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
Ensures accurate and stable scanning by maintaining a constant document speed and reducing frictional impacts, preventing temporary changes in delivery speed and improving scanning precision.
Implementation Method 1
a drive roller provided at the white bar to rotate upon receiving power to allow a document to pass between the scanning glass and the white bar
Implementation Method 2
a guide film made of an elastically deformable material to guide the document to the scanning glass
Data Source
AI summary
An image reading device and an image forming apparatus having the same. The image reading device includes an scanning glass, a white bar arranged opposite the scanning glass, and a drive roller provided at the white bar, the drive roller being rotated upon receiving power to allow a document to pass between the scanning glass and the white bar.