Image Reading Apparatus Connection Detection Using Identification Signals
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Solution Overview
Problem
Existing image reading apparatus technologies, such as those described in Japanese Patent Laid-Open No. 2004-88564, are ineffective in detecting abnormalities in CMOS sensors due to the absence of externally output reset noise and unstable voltage fluctuations, making it difficult to reliably detect abnormal connections.
Innovation Solution
An image reading apparatus with a reading unit, driving unit, and connection unit that inserts an identification signal into specific ineffective pixels not reacting to external light, allowing for connection detection by examining signal levels, enabling reliable abnormal connection detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reset noise detection is used for CCD sensors, then CCD sensor abnormalities can be detected, but this technique cannot be applied to CMOS sensors due to absence of externally output reset noise
Solution Approach 1:
The patent introduces an intermediary identification signal that is inserted into the output signal from ineffective pixels. This identification signal serves as a mediator that enables connection status detection without relying on sensor-specific characteristics like reset noise, thereby making the detection method compatible with both CCD and CMOS sensors.
Solution Approach 2:
Instead of detecting abnormalities by analyzing natural sensor outputs (reset noise for CCD), the patent inverts the approach by having the system actively insert an identification signal into the output and then detect its presence. This inversion makes the detection method universally applicable to different sensor types including CMOS sensors that do not output reset noise.
2Measurement precision
If voltage sampling is performed to detect abnormalities, then sensor output can be monitored, but the voltage fluctuates over time making stable sampling difficult
Solution Approach 1:
The patent applies preliminary action by inserting the identification signal into the output from ineffective pixels before any abnormality detection occurs. This pre-inserted signal provides a stable reference that can be detected regardless of voltage fluctuations, enabling reliable connection status determination without being affected by time-varying voltage instability.
3Reliability
If connection detection is performed using existing methods, then CCD sensor abnormalities can be detected, but the method is ineffective for CMOS sensors and cannot reliably detect abnormal connections
Solution Approach 1:
The patent achieves universality by creating a connection detection method that works with both CCD and CMOS sensors. The identification signal insertion technique into ineffective pixels provides a sensor-type-independent solution that reliably detects connection status across different sensor technologies, eliminating the limitation of CCD-specific reset noise detection.
Data Source
AI summary
An image reading apparatus includes a reading unit that has multiple pixels for performing image reading, a driving unit that outputs a driving signal to the pixels of the reading unit, and a connection unit that connects the reading unit to the main body of the image reading apparatus. An identification signal is inserted by the driving unit at a specific pixel among ineffective pixels that do not react to external light among the pixels of the reading unit, and detection of whether or not the reading unit is connected correctly to the main body of the image reading apparatus by the connection unit is performed by examining the signal level of the specific pixel.