Cover State Detection Using Light Source Modulation
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Solution Overview
Problem
Existing image reading apparatuses with automatic document feeders face challenges in accurately determining the open or closed state of the cover without sensors, leading to potential damage or suboptimal image quality, especially under bright ambient light conditions.
Innovation Solution
An image reading apparatus that includes a control device which calculates evaluation values based on read data obtained with and without the light source, determining the cover's state by comparing these values to threshold ranges, allowing for accurate determination of the cover's position without a dedicated sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor is used to detect the open or closed state of the cover, then the reliability of cover state detection is improved, but the device complexity and cost increase
Solution Approach 1:
The reading device uses its own existing components (light source and sensor) to detect the cover state without requiring a separate dedicated sensor. The sensor that originally detects reflected light from the document is also utilized to detect cover state by measuring light transmission through the cover, thereby eliminating the need for additional components and reducing structural complexity while maintaining reliable detection
Solution Approach 2:
The sensor serves dual functions: detecting the reflected light from the document during normal reading operations and detecting the cover state by measuring light transmission. This multi-functionality approach allows the same component to perform multiple tasks, reducing the overall device complexity and eliminating the need for a separate cover state detection sensor
2Measurement precision
If the light source is turned off to detect cover state, then the measurement precision is improved by avoiding ambient light interference, but the productivity decreases due to additional detection steps
Solution Approach 1:
The control device performs cover state detection before initiating the document reading operation. By determining whether the cover is closed in advance using the light transmission method, the system ensures that reading operations only proceed when the cover is properly closed, preventing image quality degradation and document damage while maintaining efficient operation flow
Solution Approach 2:
The system periodically checks the cover state using the light source and sensor before each reading operation. This periodic detection ensures that the cover is in the correct state without requiring continuous monitoring during the actual reading process, thereby maintaining measurement precision while minimizing interruptions to productivity
3Productivity
If the light source is turned on during cover state detection, then the productivity is maintained by avoiding detection delays, but the measurement precision deteriorates due to ambient light interference
Solution Approach 1:
The invention extracts the cover state detection function from the normal reading process by using a dedicated detection mode where the light source is turned on specifically for cover state measurement. This separation allows the system to maintain high productivity during normal reading operations while ensuring measurement precision during cover state detection through controlled lighting conditions
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 enables accurate determination of the cover's state, improving image quality and reducing complexity and cost by eliminating the need for a sensor, while effectively handling variations in ambient light.
Implementation Method 1
The sensor detects reflected light of light emitted toward the document from the light source and obtain a read value
Data Source
AI summary
An image reading apparatus includes a cover, a reading device including a light source and a sensor, and a control device including circuitry. The circuitry acquires first data with the light source turned off, acquires second data with the light source turned on, calculates a first evaluation value for each of plural locations of the first data, calculates a second evaluation value for each of plural locations of the second data, determines an open or closed state of the cover based on the first evaluation value and the second evaluation value, determines that the cover is open when at least one of a determination result based on the first evaluation value or a determination result based on the second evaluation value indicates the open state of the cover, and determines that the cover is closed when the two determination results both indicate the closed state of the cover.