Scanner Optical Sensor Auto-Calibration for Power Efficiency
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Solution Overview
Problem
Existing image reading apparatuses face challenges in accurately determining the insertion of a reading target medium into a conveyance path without increasing power consumption, as they require CPU operation to adjust light projection amounts before medium insertion.
Innovation Solution
An image reading apparatus that includes a generator for pulse signals, a sensor with a light projector and receiver, a peak hold circuit to store light reception peak values, and a current supply circuit to adjust light projection amounts based on these values, allowing for adjustment without CPU intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If power is supplied to the CPU in advance to adjust the light projection amount, then the light projection amount can be accurately adjusted, but the power consumption of the scanner increases
Solution Approach 1:
The light projection amount is adjusted in advance during the manufacturing process by manually adjusting the light projector before final assembly. This preliminary adjustment eliminates the need for CPU-based adjustment during operation, thereby resolving the contradiction between achieving accurate light projection adjustment and minimizing power consumption.
2Use of energy by moving object
If the light projection amount is adjusted manually during manufacturing, then power consumption is reduced, but the adjustment precision may be insufficient
Solution Approach 1:
A feedback mechanism is implemented where the light receiver detects the actual light reception amount and feeds this information back to the adjustment process. This allows for precise adjustment of the light projection amount by using the detected light reception amount as a reference, ensuring manufacturing precision while maintaining low power consumption.
3Ease of manufacture
If optical sensors with product variations are used, then manufacturing cost is reduced, but the determination accuracy of medium insertion varies
Solution Approach 1:
The system compensates for product variations in optical sensors by dynamically adjusting the light projection amount based on the actual light reception amount detected. This parameter adjustment ensures that determination accuracy is maintained across different sensor units, resolving the contradiction between using cost-effective sensors with variations and achieving consistent determination accuracy.
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
Enables accurate determination of medium insertion and efficient power management by adjusting light projection amounts autonomously, reducing power consumption and CPU dependency.
Implementation Method 1
a sensor (24) includes a light projector (24T) that projects pulsed light corresponding to the pulse signal toward the conveyance path and a light receiver (24R) disposed so as to face the light projector across the conveyance path
Data Source
AI summary
In a scanner, a pulse generator generates a pulse signal, a transmissive optical sensor includes a light projector that projects pulsed light corresponding to the pulse signal and a light receiver disposed so as to face the light projector, a peak hold circuit holds a peak value of a voltage value indicating a light reception amount of the pulsed light in the light receiver, and a first current supply circuit increases a light projection amount of the pulsed light projected from the light projector by increasing a current supplied to the light projector when the peak value is smaller than a reference value and decreases the light projection amount of the pulsed light projected from the light projector by decreasing the current supplied to the light projector when the peak value is larger than the reference value.