Scanner Power Saving via Intermittent LED Detection
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Solution Overview
Problem
Conventional auto document feeders in image forming apparatuses face high power consumption due to constant operation of the CPU for controlling and monitoring the infrared LED light emitting unit, which is necessary for document detection, making it difficult to achieve power saving modes without compromising document detection capabilities.
Innovation Solution
The implementation of a document detection sensor with a light emitting and receiving unit, a driving signal output unit for intermittent lighting, and a control unit with an interrupt port that returns to a power saving state upon detection, allowing the CPU to enter a suspended mode while still detecting document presence through a D-type flip-flop and PWM functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the infrared LED is constantly lit for document detection, then document detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by intermittently lighting the infrared LED at regular intervals instead of continuously. The lighting control unit turns the LED on and off periodically, and the detection signal output unit checks for document presence only during lighting periods. This reduces power consumption while maintaining detection capability during active intervals.
Solution Approach 2:
The patent implements dynamics by making the CPU operational state dynamic rather than static. The CPU operates actively during lighting periods to monitor detection signals, then transitions to a suspended power-saving state during non-lighting periods. This dynamic state change allows the system to balance detection reliability with power consumption requirements.
2Speed
If the CPU constantly monitors document detection signals, then detection responsiveness is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by having the CPU monitor detection signals only during predetermined lighting intervals rather than continuously. The lighting control unit and detection signal output unit are synchronized to check for document presence only when the infrared LED is illuminated, allowing the CPU to enter suspended states between monitoring periods.
Solution Approach 2:
The patent implements dynamics by transitioning the CPU between active and suspended states based on lighting intervals. The CPU dynamically switches to a suspended state after completing detection checks during lighting periods, then wakes up for the next lighting interval. This dynamic state management reduces CPU power consumption while maintaining detection responsiveness during active periods.
3Use of energy by moving object
If the CPU enters a suspended state to save power, then power consumption is reduced, but document detection capability is lost
Solution Approach 1:
The patent applies preliminary action by performing document detection checks before the CPU enters suspended state. The detection signal output unit checks for document presence during lighting intervals while the CPU is still active, ensuring detection capability is maintained before power savings begin. This preliminary detection ensures no document events are missed during subsequent suspended periods.
Solution Approach 2:
The patent uses periodic action by synchronizing detection checks with periodic lighting intervals. The CPU enters suspended state only after completing detection during each lighting period, then wakes up for the next periodic lighting interval to repeat the process. This periodic cycle ensures detection capability is continuously restored at regular intervals while maintaining power savings during non-detection periods.
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 solution reduces power consumption by enabling the CPU to enter a power saving mode without compromising document detection responsiveness, allowing for efficient power management in image processing apparatuses.
Implementation Method 1
a detection unit, having a light emitting unit and a light receiving unit for receiving light output from the light emitting unit
Data Source
AI summary
An information processing apparatus includes a light emitting unit and a light receiving unit for receiving light output from the light emitting unit, and includes a detection unit for outputting a light reception signal indicating that the light receiving unit has received light from the light emitting unit, a driving signal output unit for outputting a driving signal to the detection unit so that the light emitting unit intermittently outputs light, a detection signal output unit for outputting, based on the output driving signal and the output light reception signal, a detection signal indicating whether an object exists between the light emitting unit and the light receiving unit, and a control unit including an interrupt port to which the output detection signal is input and for returning from a power saving state in response to the detection signal being input to the interrupt port in the power saving state.