CVT Pulley Segments for Quiet Speed Control
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Solution Overview
Problem
Conventional Continuously Variable Transmission (CVT) devices used in image forming apparatuses are unable to achieve high responsiveness and control accuracy, leading to delays and image quality degradation when changing system speeds, particularly in color image forming processes where precise speed control is required.
Innovation Solution
An image forming apparatus utilizing a motor-driven variable speed transmission unit with divided pulley segments and a V-shaped belt, combined with feedback control to quickly and accurately adjust the rotation speed of the load shaft, ensuring quiet operation and precise speed changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a CVT device using belt drive is used to avoid gear noise, then quietness is improved, but response speed and control accuracy deteriorate
Solution Approach 1:
The pulley is divided into two independently controllable pulley segments that can move relative to each other along the shaft axis. This segmentation allows the V-shaped groove width to be dynamically adjusted, enabling the belt to be positioned at different radial distances from the shaft center, thereby achieving continuous transmission ratio change while maintaining quiet operation and improving response speed
Solution Approach 2:
The pulley segments are made dynamically adjustable rather than fixed. By applying driving forces to move the pulley segments along the shaft axis in real-time, the system achieves dynamic transmission ratio adjustment, which significantly improves response speed and control accuracy compared to conventional fixed-ratio belt drives
2Object-affected harmful factors
If a CVT device mechanically changes the distance between pulley segments to change speed, then quietness is improved, but control accuracy deteriorates due to large errors
Solution Approach 1:
A feedback control mechanism is implemented where the actual transmission ratio is continuously monitored and compared with the target ratio. The controller adjusts the pulley segment positions based on the detected error, enabling precise speed control within ±0.1% accuracy requirement for color image forming, while maintaining the quiet operation benefits of belt drive
Solution Approach 2:
The control system replaces purely mechanical adjustment with a combination of mechanical actuation and electronic control. Sensors detect the actual speed and position, and electronic controllers calculate and command the precise pulley segment movements, substituting imprecise mechanical linkages with electronically controlled actuation for higher accuracy
3Speed
If system speed is changed by changing gear ratio using gears, then speed control is achieved, but gear noise is generated
Solution Approach 1:
The invention replaces the traditional gear-based mechanical transmission system with a belt-driven CVT system. This substitution eliminates the toothed engagement of gears that generates noise, while achieving similar speed control functionality through continuous transmission ratio adjustment via pulley segment movement
4Reliability
If a heater with high heating capability is adopted to avoid fixing failure on special paper, then fixing reliability is improved, but power consumption and device cost increase
Solution Approach 1:
The system changes the operational parameters (speed) rather than the hardware capability (heating power). By reducing the system speed when processing special paper, the heat absorption rate of the paper is reduced, allowing the existing heater to achieve proper fixing without requiring higher power consumption or increased device cost
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 rapid and accurate system speed changes while maintaining quietness, improving image quality and reducing delays associated with speed adjustments, particularly when switching between different types of recording sheets.
Implementation Method 1
a V-shaped belt suspended between the grooves of the pair of pulleys
Data Source
AI summary
The present invention is capable of changing the system speed quickly and highly accurately while using a CVT device with an advantage in its quietness to transmit a driving force to rotative parts.Specifically, in the case of using a sheet of thick paper as a recording sheet, the controller changes, for each of the pulleys, the distance between the pulley segments (S204) while starting up the DC motor as the driving source (S202). After that, the controller performs the feedback control on the rotation of the DC motor, based on a detection signal received from the encoder of the load shaft of the driven pulley, to achieve the target rotation speed of the load shaft (S206: NO, S207).