Multiple-Reflection Moisture Sensor for Precise Sheet Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional moisture sensors struggle to accurately detect minute changes in moisture levels in sheets due to low sensitivity of light reflection changes, leading to inaccuracies in moisture detection.
Innovation Solution
A moisture sensor design that utilizes multiple reflections of light between a reflecting member and the sheet surface, combined with a semiconductor light-emitting element and a photodiode, to enhance detection accuracy by increasing the change in received light amount based on moisture content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-reflection light detection is used, then the device structure is simple, but the measurement precision is insufficient for detecting minute moisture changes
Solution Approach 1:
The patent transitions from single-reflection light detection to multiple-reflection light detection, adding the dimension of repeated optical interactions. By configuring the light source, reflecting member, and light receiver in a specific geometric arrangement where light reflects multiple times between the sheet and reflecting surface, the system amplifies moisture detection sensitivity without proportionally increasing device complexity
Solution Approach 2:
The patent introduces a reflecting member as an intermediary element between the light source and the sheet, and between the sheet and the light receiver. This intermediary enables multiple reflections by bouncing light back and forth between the sheet surface and the reflecting member, thereby enhancing the interaction between light and moisture without requiring direct complex positioning between light source and receiver
2Measurement precision
If light wavelength is changed to one more easily absorbed by moisture, then the measurement precision improves, but the light source selection becomes more restricted
Solution Approach 1:
The patent changes the parameter of light wavelength to near-infrared region (specifically around 1450nm or 1940nm where water has strong absorption characteristics). This parameter change enables highly accurate moisture detection by exploiting the strong absorption of water molecules at these wavelengths, while the use of LED technology maintains adaptability and versatility in light source implementation
3Measurement precision
If multiple reflections are implemented, then the change in received light amount increases for better detection, but the device structure becomes more complex
Solution Approach 1:
The patent designs the optical system where the reflecting member serves multiple functions: it acts as a structural support element, a light reflection surface, and a spatial positioning reference. The light source and light receiver are positioned to simultaneously achieve multiple reflections and maintain compact device geometry, making the system multi-functional without proportionally increasing 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
The proposed sensor design significantly improves detection accuracy, allowing for precise moisture measurement and enabling real-time adjustment of curl correction and transfer current, thereby enhancing image quality and consistency.
Implementation Method 1
light at a wavelength that is most easily absorbed by moisture is extracted from the light emitted from the light source by the wavelength filter
Implementation Method 2
a light-receiving element configured to receive light that is multiple reflected between the object and the first reflecting member
Implementation Method 3
a first reflecting member configured to reflect light reflected from the object toward the object
Data Source
AI summary
A moisture sensor detects moisture in an object. A first light-emitting element emits light. A first reflecting member reflects light reflected from the object toward the object. A light-receiving element receives light that is multiple reflected between the object and the first reflecting member. A controller determines an amount of moisture in the object based on a light reception result from the light-receiving element.