Document Scanner Light Source Thermal Control
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Solution Overview
Problem
Document reading apparatuses face productivity issues due to prolonged heat buildup from light sources, leading to delayed restarts even after the light source has cooled, as existing temperature detection methods are slow to reflect actual temperature changes, causing unnecessary downtime.
Innovation Solution
Incorporating a processor-controlled system with a temperature detector and timer to stop and restart the light source and document conveyance based on temperature thresholds and elapsed time, independent of the temperature detection results, ensuring timely document reading resumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature detection is used to control light source operation, then light source temperature can be monitored, but productivity decreases due to delayed restart after cooling
Solution Approach 1:
The patent applies dynamics by making the control strategy adaptive based on operating conditions. The controller switches between temperature-based control (for reliability) and time-based control (for productivity) depending on whether the light source is operating or in standby, optimizing the balance between monitoring accuracy and system throughput
Solution Approach 2:
The patent changes the control parameter from temperature-only to a combination of temperature and time parameters. By introducing time as an additional control dimension, the system can restart based on elapsed time after cooling rather than waiting for temperature threshold recovery, thereby improving productivity while maintaining reliability through dual-parameter monitoring
2Reliability
If thermistor detects temperature of light source, then temperature monitoring is achieved, but response time is slow due to heat capacity of mounting structure
Solution Approach 1:
The patent applies preliminary action by pre-cooling the light source during standby periods and pre-calculating optimal restart timing based on elapsed time. This allows the system to be ready for immediate restart without waiting for the thermistor to detect temperature changes, effectively decoupling the restart decision from the slow temperature detection response
Solution Approach 2:
The patent introduces time as an intermediary parameter between the cooling process and the restart decision. Instead of directly using temperature detection results to control restart timing, the system uses elapsed time since cooling start as a mediator to trigger restart, bypassing the slow temperature response while ensuring safe operating conditions
3Reliability
If document reading restarts based on thermistor temperature, then safety is ensured, but unnecessary downtime occurs when light source has cooled but thermistor still shows high temperature
Solution Approach 1:
The patent makes the control strategy dynamic by adapting the restart criterion based on system state. During active operation, temperature-based control ensures safety. During standby cooling periods, time-based control allows earlier restart when appropriate, reducing unnecessary downtime while maintaining safety through contextual adaptation of control parameters
Solution Approach 2:
The patent applies partial action by using temperature monitoring selectively rather than continuously for restart decisions. Temperature detection ensures safety when needed, but time-based control takes over for restart timing to avoid excessive waiting, achieving sufficient safety without the penalty of overly conservative temperature-threshold-only control
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 minimizes downtime and increases productivity by allowing the document reading apparatus to restart operations sooner, independent of temperature detection delays, thus reducing waiting times for users and maintaining consistent document processing speed.
Implementation Method 1
A detector provided on the substrate is configured to detect a temperature of the light source
Implementation Method 2
A sensor includes a light-receiving element that receives light emitted from the light source and reflected by the conveyed document
Data Source
AI summary
In a case where a temperature detected by a detector is greater than a threshold, one or more processors controls a light source not to emit light and stops conveyance of a document by a conveyance unit. In a case where a predetermined amount of time has elapsed from when the one or more processors controls the light source not to emit the light, the one or more processors controls the light source to emit the light and starts conveyance of the document by the conveyance unit, regardless of a detection result of the detector.