Hardware Stop Control Circuit for Fixing Device Motor Safety
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Solution Overview
Problem
Conventional image forming apparatuses face issues with motor control reliability due to software-based control systems, leading to potential motor breakdowns and increased manufacturing costs from high-accuracy encoders, especially when the control device fails or lacks necessary ports for sensor output.
Innovation Solution
A fixing device with a hardware-based stop control circuit that receives output from a detecting member to safely stop the motor without software control, using a motor that can rotate in both directions to adjust fixing pressure and a control section that issues voltage instructions for motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If software control is used to control motor rotation, then control flexibility is improved, but system reliability deteriorates due to potential control device failure
Solution Approach 1:
The control system is segmented into two independent parts: a software control device for normal operation and a hardware stop control circuit for safety. The hardware circuit independently monitors motor rotation via a detecting member and can stop the motor without software intervention, thus maintaining reliability while preserving software flexibility.
Solution Approach 2:
A hardware stop control circuit acts as an intermediary between the detecting member and the motor drive circuit. This intermediary circuit provides a reliable fallback mechanism that operates independently of the software control device, ensuring system reliability while allowing software control flexibility.
2Measurement precision
If high-accuracy encoders are installed to improve motor control precision, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using expensive high-accuracy encoders, the patent employs a simple detecting member that detects motor rotation through basic principles. This cheaper detection method achieves sufficient precision for the application while significantly reducing device complexity and cost.
Solution Approach 2:
The patent replaces complex mechanical encoder systems with a simpler detection mechanism that uses basic electrical circuits to monitor motor rotation. This substitution maintains adequate measurement precision while eliminating the need for complex mechanical components.
3Device complexity
If the control device lacks necessary ports for sensor output, then device simplicity is maintained, but control functionality is limited
Solution Approach 1:
The hardware stop control circuit serves as an intermediary that bridges the gap between the simple control device and the motor control requirements. It provides the necessary control functionality through hardware logic without requiring additional ports or complexity in the main control device.
Solution Approach 2:
The hardware stop control circuit is self-sufficient in monitoring motor rotation and executing stop commands. It does not require complex processing or additional ports from the main control device, maintaining device simplicity while providing essential control functionality.
Data Source
AI summary
A fixing device includes a heating rotating member, a pressing rotating member, a motor, a fixing pressure adjustment mechanism, a control section, a motor drive section, a detecting member, and a stop control circuit. The heating rotating member heats a paper sheet. The pressing rotating member is pressed to the heating rotating member. The motor can rotate in both forward and backward directions. The fixing pressure adjustment mechanism moves a rotating member to be moved between first and second positions. The control section includes a control device, issues an instruction of voltage to be applied to the motor. The motor drive section controls the voltage to be applied to the motor. The detecting member detects that the rotating member to be moved reaches the first position. The stop control circuit stops the motor without software control when the rotating member to be moved reaches the first position.