Dual-Surface Image Reading Using Nonoverlapping Light Timing
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Solution Overview
Problem
Existing image reading devices face challenges in reducing the image reading time for the initial document sheet and preventing the formation of low-quality images due to overlapping lighting times of light sources for reading both surfaces of a document sheet.
Innovation Solution
The image reading device includes a control portion that controls the lighting times of the first and second light sources in the first and second reading portions such that they do not overlap, allowing for simultaneous setting and adjustment of the front and back surface CIS sensors without compromising image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light sources for reading both surfaces of a document sheet are operated simultaneously, then image reading capability is improved, but overlapping lighting times cause low-quality images
Solution Approach 1:
The patent divides the lighting operation into separate time slots for the first light source (front surface reading) and the second light source (back surface reading). By segmenting the lighting operations temporally, the system enables both surfaces to be read without light overlap, ensuring high image quality for both surfaces while maintaining the capability to read both sides of the document.
2Manufacturing precision
If white reference data is generated for both surfaces, then image quality is improved, but reading time for initial document sheet increases
Solution Approach 1:
The patent performs white reference data generation as a preliminary action before actual image reading. By capturing reference data from white reference plates for both surfaces in advance and storing it, the system eliminates the need to perform time-consuming reference measurements during the actual reading process, thereby reducing overall reading time while maintaining high image quality through accurate white balance correction.
3Manufacturing precision
If light sources are controlled to avoid overlapping lighting times, then image quality is maintained, but device complexity increases
Solution Approach 1:
The patent implements periodic action by using a control unit to sequentially activate light sources in distinct time periods. The control unit manages the lighting sequence by first activating the front surface light source, capturing the image, then activating the back surface light source after a predetermined time interval. This periodic control approach maintains simple hardware architecture while ensuring no light overlap, thus maintaining image quality without significantly increasing device complexity.
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 approach reduces the image reading time for the initial document sheet and prevents the formation of low-quality images by ensuring appropriate white reference data generation for both surfaces.
Implementation Method 1
generate first white reference data by using reflected light reflected from the first white reference plate
Implementation Method 2
generate second white reference data by using reflected light reflected from the second white reference plate
Data Source
AI summary
An image reading device includes: a first reading portion configured to read an image of a sheet; a second reading portion disposed below a contact glass; a first white reference plate disposed in a conveying portion to face the first reading portion; a second white reference plate disposed in the conveying portion at a reference position that can face the second reading portion; and a control portion configured to light a first light source and generate first white reference data by using reflected light reflected from the first white reference plate, and light a second light source and generate second white reference data by using reflected light reflected from the second white reference plate. The control portion controls the first light source and the second light source such that a lighting time of the first light source does not overlap with a lighting time of the second light source.