Document Reading Device Stain-Free Optical Exposure
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Solution Overview
Problem
Document reading devices face issues with stains on support means, such as ink, pencil lead powder, and white-out, which affect image quality during document transportation, especially when the distance between the support means and transport path forming member is increased to prevent staining, leading to reduced focus area and image quality deterioration.
Innovation Solution
A document reading device with a movable exposure member and a guide member that forms a predetermined inclination angle with the support means, allowing the detection of a stain-free area, enabling the exposure member to stop at a position within a preferable distance range of 0.5 mm to 1.0 mm from the leading end of the guide member, thus avoiding the need to increase the distance between the support means and transport path forming member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the distance between the support means and transport path forming member is increased to 1.0 mm to 1.5 mm to prevent stains, then staining resistance is improved, but the depth of focus area is reduced and image quality deteriorates
Solution Approach 1:
A guide member is introduced as an intermediary component between the document and support means. The guide member has a leading end that defines a stain-free area on the support means, allowing the exposure member to position readings within this clean zone without requiring increased distance between support means and transport path forming member.
Solution Approach 2:
The system pre-identifies a stain-free area on the support means by detecting the leading end position of the guide member. The exposure member then positions its reading operation within this predetermined clean area before staining can occur, proactively avoiding the harmful effect rather than reactively increasing distance.
2Stability of the object's composition
If the optical reading means is kept stationary with transparent support means, then reading stability is improved, but stains from document friction accumulate on the support means affecting subsequent readings
Solution Approach 1:
The system pre-identifies a stain-free area on the support means by detecting the leading end position of the guide member. The exposure member then positions its reading operation within this predetermined clean area before staining can occur, proactively avoiding the harmful effect rather than reactively increasing distance.
3Manufacturing precision
If the distance between support means and transport path forming member is kept at 0.5 mm to 1.0 mm for optimal focus, then image quality is maintained, but document friction causes stains on the support means
Solution Approach 1:
A guide member is introduced as an intermediary component between the document and support means. The guide member has a leading end that defines a stain-free area on the support means, allowing the exposure member to position readings within this clean zone without requiring increased distance between support means and transport path forming member.
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 solution allows for high-quality image reading of transported documents without being affected by stains on the support means, maintaining a preferable distance range between the support means and transport path forming member, ensuring optimal image capture while preventing staining.
Implementation Method 1
optical reading means for reading a document image by emitting light from the exposure member onto the document and guiding received reflected light from the document which has passed over the reading position to the following optical system so as to sequentially detect the reflected light
Data Source
AI summary
A document reading device includes a document transport and, for reading a document image, an optical reader having a movable exposure which stops at a predetermined reading position and emits light onto the document. A guide member guides the document to the reading position to form a predetermined inclination angle with respect to a flat-plate face of a support, which supports the document being transported when it passes over the reading position. A transport path is formed with the support so that the document passing over the reading position is transported along the flat-plate face. A detection member detects a leading end position of the guide member, the predetermined reading position being set to within a predetermined distance in a transport direction from the leading end of the guide member, which is known beforehand to be stain-free.