Image Forming Apparatus Power State Transition Logic
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Solution Overview
Problem
Image forming apparatuses often undesirably return to a normal mode from a power-saving mode due to human detection, even if the user intended to transition to the power-saving mode and has left the device.
Innovation Solution
The apparatus includes a control device that counts the number of times a detection device detects a person within a predetermined period after the user initiates the transition to the power-saving mode. If the count reaches a specified number, the apparatus returns to the normal mode; otherwise, it remains in the power-saving mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the apparatus returns to normal mode when a person is detected after transitioning to power-saving mode, then user convenience is improved, but power-saving effectiveness deteriorates due to premature mode switching
Solution Approach 1:
The control device performs preliminary action by counting the number of times a person is detected within a predetermined period after the power-saving mode transition is initiated. This counting mechanism is established before making the final decision to return to normal mode, preventing premature mode switching while still enabling convenient user access when needed.
2Measurement precision
If a high-performance human detection sensor is used to accurately detect user approach and departure, then detection precision is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using a high-performance sensor with complex capabilities, the invention changes the parameter of detection by using a simpler sensor combined with a time-based counting mechanism. The control device counts detection events within a predetermined period, transforming the approach from relying on sensor precision to relying on detection frequency measurement, thereby reducing device complexity while maintaining functional effectiveness.
3Loss of energy
If the apparatus suspends return to normal mode until the detection sensor first detects a person and then no longer detects the person, then power-saving effectiveness is improved, but user convenience deteriorates when multiple users need access
Solution Approach 1:
The control device establishes a counting mechanism in advance that tracks the number of times a person is detected within a predetermined period. This preliminary counting action enables the system to distinguish between a single user leaving (who may be detected by the sensor) and multiple users needing access, thereby maintaining power-saving effectiveness while improving convenience for multi-user scenarios.
Solution Approach 2:
The system implements feedback by continuously monitoring detection events and using the count of detections within the predetermined period to determine whether to return to normal mode. This feedback mechanism allows the apparatus to adapt its behavior based on usage patterns, returning to normal mode only when sufficient detection activity indicates multiple users need access, rather than suspending return indefinitely.
Data Source
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AI summary
An image forming apparatus (1) includes an image forming device (12), an operation device (16), a detection device (21), and a control device (100) functioning as a controller (10). When accepting through the operation device (16) an instruction to transition to a second power state, the controller (10) allows the image forming apparatus (1) to transition from a first power state to the second power state. The controller (10) counts a number of times that the detection device (21) has detected a person existing within a predetermined range within a predetermined first period from a time of acceptance of the instruction to transition. When the counted number of times reaches a predetermined number of at least two, the controller (10) returns the image forming apparatus (1) from the second power state to the first power state. When the counted number of times falls short of the predetermined number, the controller (10) keeps the image forming apparatus (1) in the second power state.