Planetary Gear Switching Control for Accurate Medium Positioning
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Solution Overview
Problem
Medium processing devices, such as scanners and printers, face issues with incomplete document feeding due to inefficient switching between gear states in planetary gear mechanisms, leading to suboptimal processing results when the sub gear and motive force transmission gear do not mesh smoothly.
Innovation Solution
A medium processing device with a motive force switching unit that includes a main gear and a sub gear, capable of switching between meshed and disengaged states, along with a load detection unit and controller, which determines the meshed state based on motor load and applies appropriate control to ensure proper processing, using threshold values and drive amounts to prevent false detection and ensure accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a planetary gear mechanism is used to switch motive force transmission states, then the device can efficiently switch between motor-driven and free-wheeling states, but the gear meshing may not transition smoothly leading to inaccurate medium positioning
Solution Approach 1:
The controller monitors the load of the motor during gear switching and uses this feedback to determine when the sub gear has successfully meshed with the motive force transmission gear. Based on this feedback, the controller adjusts the drive amount of the motor to compensate for positioning errors caused by delayed or incomplete meshing, thereby maintaining positioning accuracy while preserving the efficiency benefits of the planetary gear mechanism.
2Reliability
If the sub gear switches from disengaged to meshed state, then motive force transmission is established, but the leading ends of gear teeth may abut preventing quick transition to meshed state
Solution Approach 1:
The controller performs preliminary positioning of the medium based on the drive amount before the gear switching is complete. By anticipating the delay in meshing transition and pre-adjusting the medium position, the system ensures that the medium will be at the correct position once the gear meshing is established, thereby reducing the effective time loss and ensuring reliable motive force transmission.
3Ease of operation
If the controller uses fixed drive amount for medium feeding, then the control is simple, but positioning accuracy deteriorates when gear meshing is delayed
Solution Approach 1:
The controller dynamically adjusts the drive amount of the motor based on the actual gear meshing state detected through load monitoring. Instead of using a fixed drive amount, the system adapts the drive amount in real-time according to whether the sub gear has successfully meshed with the motive force transmission gear, thereby maintaining positioning accuracy while adding minimal complexity to the control logic.
Data Source
AI summary
A medium processing device includes a processor, a feed roller, a motor, a motive force transmission gear that transmits motive force of the motor to the feed roller, a switching unit that is configured including a main gear and a sub gear that meshes with the main gear and moves in planetary motion around the main gear, and that switches accompanying rotation direction switching of the main gear between a meshed state and a disengaged state between the sub gear and the motive force transmission gear, a load detection unit that detects load of the motor, and a controller. The controller controls the motor and the processor according to the load detected by the load detection unit at switching of the sub gear from the disengaged state to the meshed state.