Inner Rotor Brushless DC Motor Control for Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face inefficiencies in energy use and motor durability due to the need for large stepping motors to handle load fluctuations, and DC motors lack precise position and hold control.
Innovation Solution
An image forming apparatus utilizing an inner rotor brushless DC motor with a rotation detector and controller that adjusts power supply based on target drive signals and detection signals to achieve precise speed and position control, similar to stepping motors, while being more energy-efficient and durable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stepping motor is used to achieve accurate position control and hold control, then position control precision is improved, but energy efficiency deteriorates and motor weight increases
Solution Approach 1:
The patent changes the operating parameters of the DC motor by using pulse width modulation to vary the duty cycle, enabling the motor to operate in discrete steps similar to a stepping motor while maintaining the energy efficiency of DC motor operation. The controller adjusts the voltage and current parameters dynamically based on load conditions.
Solution Approach 2:
The patent implements feedback control using an encoder to detect the motor's position and speed, then feeds this information back to the controller. The controller uses this feedback to adjust the pulse width modulation duty cycle, enabling closed-loop position control that matches stepping motor precision while maintaining DC motor energy efficiency.
2Reliability
If a stepping motor is used to handle load fluctuations, then position control reliability is improved, but motor weight increases
Solution Approach 1:
The patent enables a lighter DC motor to handle load fluctuations by dynamically changing its operating parameters through pulse width modulation. The controller adjusts the voltage and current delivery to match the actual load requirements, allowing the motor to provide sufficient torque during load changes without requiring the excessive size of a stepping motor.
Solution Approach 2:
The patent makes the motor control dynamic by using real-time feedback from the encoder to continuously adjust the pulse width modulation duty cycle. This dynamic control allows the motor to adapt to load fluctuations and maintain position control reliability while using a lighter motor design.
3Use of energy by moving object
If a DC motor is used to improve energy efficiency, then energy efficiency is improved, but position control precision deteriorates
Solution Approach 1:
The patent overcomes the position control limitation of DC motors by implementing closed-loop feedback control. The encoder detects the motor's actual position and speed, and the controller uses this information to adjust the pulse width modulation duty cycle, enabling the DC motor to achieve stepping motor-level position control precision while maintaining energy efficiency.
Solution Approach 2:
The patent replaces the mechanical step-by-step operation of a stepping motor with an electronically controlled DC motor using pulse width modulation. This substitution allows continuous control of motor speed and position through electrical parameters rather than mechanical construction, achieving both energy efficiency and precision control.
4Weight of moving object
If a DC motor is used to reduce motor weight, then motor weight is reduced, but responsiveness at acceleration and deceleration deteriorates
Solution Approach 1:
The patent enhances the responsiveness of the lightweight DC motor by implementing dynamic control through pulse width modulation. The controller can rapidly change the duty cycle to provide high current during acceleration and deceleration phases, enabling the motor to respond quickly despite its reduced weight and inertia.
Solution Approach 2:
The patent improves acceleration and deceleration responsiveness by dynamically changing the electrical parameters delivered to the motor. During high-demand phases, the controller increases the voltage and current delivery through adjusted pulse width modulation, allowing the lightweight motor to achieve stepping motor-level responsiveness.
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
The solution enables high energy efficiency, reduced motor weight, and improved responsiveness at acceleration and deceleration, matching the performance of stepping motors with enhanced durability and precise control.
Implementation Method 1
inner rotor brushless DC motor (101) having an output shaft (124), a driver (125) to supply power to drive the inner rotor brushless DC motor (101)
Implementation Method 2
a rotation detector (122, 123) to detect an amount of rotation and a direction of rotation of the output shaft (124)
Implementation Method 3
The controller controls a speed of rotation of the inner rotor brushless DC motor by varying the signal output to the driver based on the target drive signal and the detection signal
Data Source
AI summary
A drive unit, which can be included in an image forming apparatus with peripherals disposed thereto and use a control method therefore, includes an inner rotor brushless DC motor, a driver, a rotation detector, and a controller. The driver supplies power to drive the brushless DC motor. The rotation detector detects an amount and direction of rotations of an output shaft. The controller controls the rotations of the brushless DC motor and obtains a target drive signal of the brushless DC motor externally and a detection signal from the rotation detector and outputs a signal to the driver. The controller controls a speed of rotation of the brushless DC motor by varying the signal output to the driver based on the target drive signal and the detection signal.