Image Forming Apparatus Sub CPU Low-Power Mode Transition
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Solution Overview
Problem
The existing image forming apparatuses take a long time to shift from a normal operation mode to a low-power consumption mode due to the increased amount of information transmitted when multiple types of interrupt signals serve as return triggers, leading to prolonged communication times.
Innovation Solution
The apparatus includes a first control unit, a second control unit, and a notification unit that transmits mode instruction information to the second control unit when shifting to a low-power consumption mode, allowing the second control unit to store and set units associated with the mode, thereby reducing the information required for determining return triggers and minimizing communication time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main CPU transmits information related to the type of interrupt signal serving as a return trigger to the sub CPU when shifting to low-power consumption mode, then the sub CPU can correctly identify return triggers, but the amount of information transmitted increases and communication time increases
Solution Approach 1:
The sub CPU preliminarily determines whether each interrupt signal is a return trigger based on pre-stored correspondence between low-power consumption modes and interrupt signal types. This preliminary action eliminates the need for the main CPU to transmit detailed mode information, significantly reducing communication time while ensuring reliable return trigger identification.
2Reliability
If the main CPU transmits detailed mode instruction information to the sub CPU, then the sub CPU can accurately determine return triggers, but the processing time and communication overhead increase
Solution Approach 1:
The sub CPU independently determines return triggers using pre-stored correspondence information between low-power consumption modes and interrupt signal types. This self-service approach eliminates dependency on detailed information transmission from the main CPU, thereby improving transition speed while maintaining accurate return trigger determination.
3Adaptability or versatility
If the apparatus supports multiple types of low-power consumption modes with different return triggers, then the system has higher versatility, but the amount of information to be transmitted increases
Solution Approach 1:
The system preliminarily establishes correspondence between multiple low-power consumption modes and their respective interrupt signal types in the sub CPU's storage. This preliminary configuration enables the sub CPU to handle diverse modes independently without requiring extensive information transmission, thus supporting high versatility with minimal information exchange.
Data Source
AI summary
An image forming apparatus capable of reducing execution time of a process for shifting the image forming apparatus from a normal operation mode to a low-power consumption operation mode. A sub interrupt controller 113 is connected to units and performs notification to a sub CPU in accordance with occurrence of a return trigger in any of the units. When shifting from the normal operation mode to the low-power consumption operation mode, a main CPU transmits mode instruction information indicative of the low-power consumption operation mode to the sub CPU. The sub CPU stores one or a plurality of units associated with the low-power consumption operation mode in advance, and sets one or a plurality of units in the sub interrupt controller, based on the mode instruction information and the plurality of units stored in association with the low-power consumption operation mode.