Stepping Motor Control Switching for Vibration Reduction
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Solution Overview
Problem
Conventional stepping motors in image forming apparatuses experience middle-range vibration phenomena due to variations in coil properties, limiting their operational speed range and causing malfunctions such as loss of synchronization or motor stopping.
Innovation Solution
An image forming apparatus employing a multi-phase excitation mode with a constant-voltage control unit, a constant-current control unit, a measuring unit, a chopping count determination unit, and a control switching unit to dynamically switch between control methods based on chopping count, preventing middle-range vibration by switching to constant-voltage control when chopping count is low and maintaining constant-current control otherwise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant-current control method is employed to prevent overheating and damage, then reliability is improved, but middle-range vibration phenomenon occurs due to torque variations between phases
Solution Approach 1:
The patent applies dynamics by making the control method adjustable based on operating conditions. The control unit dynamically switches between constant-voltage and constant-current control methods depending on the rotation speed range, allowing the system to adapt to different operational states and eliminate torque variations in the middle-speed range while maintaining reliability at low speeds.
Solution Approach 2:
The patent changes the control parameter from fixed constant-current control to variable control that switches between constant-voltage and constant-current methods. By changing the control parameter based on rotation speed feedback, the system resolves torque variations in the middle-speed range while maintaining the benefits of constant-current control at low speeds.
2Object-generated harmful factors
If constant-voltage control method is employed, then middle-range vibration phenomenon is prevented, but large current flows causing overheating and damage at low speeds
Solution Approach 1:
The system dynamically selects the control method based on rotation speed. At low speeds where constant-voltage control would cause overheating, the system switches to constant-current control. At middle and high speeds where constant-current control causes vibration, the system uses constant-voltage control, thus preventing harmful vibrations while maintaining reliability.
Solution Approach 2:
The control parameter is changed from fixed to variable based on rotation speed feedback. The control unit monitors rotation speed and switches between control methods accordingly, preventing both overheating at low speeds and vibration at middle speeds through parameter adaptation.
3Productivity
If stepping motor speed is increased to improve productivity, then productivity is improved, but middle-range vibration phenomenon causes loss of synchronization or motor stopping
Solution Approach 1:
The system enables high-speed operation for improved productivity by using constant-voltage control in the middle-speed range, which prevents vibration and maintains synchronization stability. The dynamic switching allows the motor to operate reliably across a wider speed range, achieving both high productivity and stable synchronization.
Solution Approach 2:
By changing the control method based on speed feedback, the system allows operation at higher speeds that improve productivity while maintaining synchronization stability through appropriate control method selection. The parameter change enables the motor to avoid vibration zones and operate reliably at high speeds.
4Device complexity
If conventional control methods are used, then device complexity is low, but speed range is limited due to vibration phenomenon
Solution Approach 1:
The control system incorporates dynamic switching between two control methods based on rotation speed feedback. This adds moderate complexity but enables operation across a wide speed range from low to high speeds, significantly improving adaptability while maintaining manageable system complexity through feedback-based automatic switching.
Solution Approach 2:
The system uses parameter changes by switching control methods based on speed feedback. This approach extends the operational speed range from limited conventional ranges to a wide range covering low, middle, and high speeds, improving versatility while keeping the control logic relatively simple through feedback-based decision making.
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 allows the stepping motor to operate stably across a wider speed range, preventing torque imbalances and overheating, thus enhancing productivity and reliability by avoiding middle-range vibration phenomena.
Implementation Method 1
a constant-current control unit configured to control the drive of the stepping motor by regulating an amount of current for each phase by a chopping control
Implementation Method 2
a measuring unit configured to measure a chopping count of each phase on a per-step basis
Data Source
AI summary
An image forming apparatus drives and rotates at least one of a photosensitive drum and a transport roller with use of a stepping motor in a multi-phase excitation mode. The image forming apparatus includes: a constant-voltage control unit controlling the stepping motor by applying a constant voltage for each phase; a constant-current control unit controlling the stepping motor by regulating an amount of current for each phase by a chopping control; a measuring unit measuring a chopping count of each phase on a per-step basis; a chopping count determination unit determining whether the chopping count of each phase is less than or equal to a predetermined count; and a control switching unit causing the constant-voltage control unit to control the stepping motor when the chopping count determination unit determines affirmatively, and causing the constant-current control unit to control the stepping motor when the chopping count determination unit determines negatively.