Stepper Motor Control for Printer Printhead Pressure
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Solution Overview
Problem
Existing printers face challenges in achieving precise control of printhead pressure and position, leading to inefficiencies and heat generation in motor windings due to high torque requirements and inadequate control over motor output.
Innovation Solution
A printer system utilizing a stepper motor with a sensor and controller to generate control signals that adjust the magnetic field's orientation and magnitude, allowing for precise and adaptable control of motor output torque, reducing the risk of stalling and heat generation by using positional feedback to optimize field angle and current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If high torque levels are used to press the printhead into contact with the printing surface, then adequate printing pressure is achieved, but significant heat is generated in motor windings and the motor size increases
Solution Approach 1:
The system employs a sensor to detect the actual position of the printhead and feeds this information back to the controller. The controller adjusts the motor drive signals based on this feedback to maintain the desired printing pressure, preventing excessive torque application and reducing heat generation in the motor windings.
Solution Approach 2:
The system dynamically adjusts motor control parameters (such as current magnitude and pulse width) based on real-time position feedback. By changing these parameters adaptively, the system achieves adequate printing pressure only when needed, rather than continuously applying high torque, thus reducing heat generation and allowing for smaller motor design.
2Reliability
If high torque levels are used to ensure adequate printing pressure, then printing reliability is improved, but the motor and power supply size must increase
Solution Approach 1:
Position feedback from the sensor allows the controller to maintain reliable printing pressure by adjusting motor output in real-time. This ensures adequate pressure is applied during printing while avoiding continuous high-torque operation, enabling the use of a smaller, lighter motor that would not be capable of sustained high-torque output.
Solution Approach 2:
The system transitions from static high-torque operation to dynamic torque control. The motor operates at variable torque levels based on real-time printing needs, applying high torque only momentarily during contact printing and reducing torque during non-printing phases. This dynamic operation enables reliable printing with a smaller motor design.
3Manufacturing precision
If precise control of printhead pressure and position is achieved through advanced motor control, then print quality is improved, but control system complexity increases
Solution Approach 1:
The sensor provides position feedback to the controller, enabling closed-loop control of printhead position and pressure. This feedback mechanism allows precise control of printing parameters to improve print quality while keeping the control system relatively simple by using straightforward position-based control algorithms rather than complex multi-parameter control.
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 enables accurate and efficient control of printhead pressure and position, minimizing heat generation and allowing for smaller motor and power supply usage while maintaining optimal torque output, thereby improving print quality and efficiency.
Implementation Method 1
The control signals for the stepper motor are arranged to cause a magnetic field to be generated by windings of the stepper motor
Implementation Method 2
a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor
Data Source
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AI summary
A printer comprising a printhead configured to selectively cause a mark to be created on a substrate, a stepper motor having an output shaft coupled to the printhead, the stepper motor being arranged to vary the position of the printhead, a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor, and a controller arranged to generate control signals for the stepper motor. Said control signals being at least partially based upon an output of said sensor and at least partially based upon a target position. Said control signals for the stepper motor are arranged to cause a magnetic field to be generated by windings of the stepper motor. A field angle being defined between an angular position of the output shaft of the stepper motor, and an orientation of the generated magnetic field. Said control signals comprise a first control signal configured to cause said field angle to have a predetermined value, and a second control signal configured to cause said magnetic field to have a predetermined magnitude, and said controller is configured to vary said first and second control signals based upon said target position and said output of said sensor.