Reference Member Isolation for Shading Correction
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Solution Overview
Problem
Conventional image reading apparatuses face challenges in performing accurate shading correction due to soiling of the reference member, which leads to variations in color and brightness in read images, requiring frequent cleaning and complicating the apparatus design.
Innovation Solution
The image reading apparatus isolates the reference member from the conveying path by placing it on the contact glass, ensuring it remains clean and protected from dust and paper powder, allowing for accurate shading correction without manual cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the reference member is disposed on the conveying path for easy access by the image sensor, then the reading operation is simplified, but the reference member gets soiled by dust and paper powder requiring frequent cleaning
Solution Approach 1:
The reference member is extracted from the conveying path and placed on the contact glass surface, separating it from the area where originals are conveyed. This extraction prevents dust and paper powder from soiling the reference member while maintaining easy access for the image sensor during reference reading operations.
Solution Approach 2:
The contact glass serves as an intermediary surface that hosts the reference member. By placing the reference member on the contact glass rather than directly in the conveying path, the system uses the contact glass as a mediator to protect the reference member from contamination while still allowing the image sensor to read it when needed.
2Measurement precision
If the reference member is frequently cleaned to maintain image quality, then shading correction accuracy is preserved, but maintenance time and operational complexity increase
Solution Approach 1:
By extracting the reference member from the conveying path and placing it on the contact glass, the system eliminates the need for frequent cleaning operations. The reference member remains in a protected environment where it is not exposed to dust and paper powder, thereby maintaining shading correction accuracy without requiring maintenance time.
3Ease of operation
If the reference member is protected from soiling by isolating it from the conveying path, then cleaning frequency is reduced, but the apparatus design becomes more complex
Solution Approach 1:
The reference member is merged with the contact glass surface, utilizing the existing contact glass structure to host the reference member. This merging approach does not require additional complex structures or mechanisms, as it simply places the reference member on the contact glass where it can be easily accessed by the image sensor while protected from contamination.
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 enables precise shading correction, maintaining image quality and reducing maintenance needs by preventing soiling of the reference member, thus ensuring consistent and accurate image reading performance.
Implementation Method 1
the original is illuminated with light from a light source, and reflected light from the original is focused by a rod lens array or the like, whereby the image on the original is read
Implementation Method 2
reflected light from the original is focused by a rod lens array or the like, whereby the image on the original is read
Implementation Method 3
the image on the original is read e.g. by a line image sensor
Data Source
AI summary
An image reading apparatus which is capable of performing accurate shading correction with simple arrangement while preventing a reference member from being scratched and preventing paper powder and the like dust from being deposited on the reference member. The image reading apparatus includes an image reading unit in which a contact glass guides an original on an image reading location. The contact glass is held by a glass holding member. A line image sensor reads the image on the original conveyed on the image reading location, through the contact glass. The image reading unit further includes a reference member whose image is readable by the image sensor, and a moving mechanism to move the image sensor so as to enable the image sensor to alternatively read the original and a reference surface of the reference member.