Brushless Motor Sheet Stacking Device Control
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Solution Overview
Problem
Conventional discharge trays using DC motors for sheet stacking in image forming apparatuses face challenges with variable moving speeds due to load, leading to misalignment and require complex control systems, while brushless motors increase costs and noise when used for high-load conditions.
Innovation Solution
A sheet stacking device with a brushless motor-driven lifting unit, controlled by a CPU that adjusts the motor speed based on the position of the stacking tray using position detecting sensors, allowing for precise control and reduced noise and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a DC brush motor is used as the driving source for the discharge tray, then the motor can handle large loads, but the rotational speed becomes inversely proportional to the load amount and requires complex control systems
Solution Approach 1:
The patent replaces the DC brush motor with a brushless motor (BLM), which is a type of motor that uses electronic commutation instead of mechanical brushes. This substitution eliminates the need for complex control systems while maintaining the ability to handle large loads, as the brushless motor provides more stable rotational speed characteristics under varying load conditions.
Solution Approach 2:
The patent changes the motor type parameter from DC brush motor to brushless motor, which fundamentally alters the motor's operational characteristics. The brushless motor maintains more consistent rotational speed across different load conditions, eliminating the inverse proportionality issue and reducing control system complexity while preserving load handling capability.
2Manufacturing precision
If the discharge tray moves up immediately when sheets are removed, then sheet alignment is maintained, but the moving-up time becomes variable depending on the number of stacked sheets
Solution Approach 1:
The patent implements a feedback control system using a position detection unit that continuously monitors the discharge tray's position. The control unit receives this position information and adjusts the brushless motor's driving speed accordingly, enabling the tray to move up at the appropriate speed to maintain sheet alignment while minimizing unnecessary waiting time.
Solution Approach 2:
The patent makes the driving speed dynamic by allowing it to vary based on real-time position feedback. The control unit adjusts the motor speed according to the detected tray position, enabling optimal performance that balances alignment accuracy with reduced moving-up time variability.
3Reliability
If a brushless motor is used for high-load conditions, then reliability and lifetime are improved, but noise and cost increase
Solution Approach 1:
The patent applies partial action by using the brushless motor only when necessary (when load requirements demand it) rather than operating at full capacity continuously. The control unit adjusts the motor speed based on actual load conditions, reducing noise generation during low-load operations while maintaining reliability when high load is required.
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 accurate and efficient control of the stacking tray's movement, reducing noise and costs, while maintaining high reliability and extending the motor's lifetime by optimizing the motor speed according to the load and position.
Implementation Method 1
a position detecting unit that detects a position of the sheet stacking unit
Implementation Method 2
a sheet stacking device including a sheet stacking unit that stacks sheets thereon and that is movable up and down; a lifting unit that moves the sheet stacking unit up and down; a driving unit that drives the lifting unit
Data Source
AI summary
A sheet stacking unit that stacks sheets thereon is movable up and down. A lifting unit moves the sheet stacking unit up and down. A driving unit drives the lifting unit. A control unit controls a driving speed of the driving unit. A position detecting unit detects a position of the sheet stacking unit in an up-and-down direction. The control unit controls the driving speed according to the position of the sheet stacking unit detected by the position detecting unit.