Switching Gear Restraint for Image Scanner Motor Torque Control
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Solution Overview
Problem
The existing image reading apparatuses face issues where the switching gear cannot be appropriately separated from the feeding device-side or moving device-side transmission gears due to insufficient reaction forces, leading to potential stepping out of the switching gear's rotation from the motor's rotation.
Innovation Solution
The apparatus includes a restraint member that applies a restraint force to the switching gear, and a motor control unit generates a larger torque than the moving reading torque to securely switch the switching gear between positions, preventing it from stepping out during the switching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one motor drives both the feeding device and the moving device through a switching gear, then the device complexity is reduced, but the reliability of gear switching deteriorates due to insufficient reaction force causing the switching gear to step out from motor rotation
Solution Approach 1:
The restraint member applies a restraint force in the opposite direction to the switching gear's movement, providing a counterbalancing force that ensures reliable disengagement from the transmission gear. This counterforce mechanism prevents the switching gear from stepping out during position transitions, resolving the reliability issue while maintaining the single-motor configuration.
Solution Approach 2:
The restraint member is configured to apply a restraint force before and during the switching gear's position change, proactively preventing unwanted movement or stepping out. This preliminary counter-action ensures that the switching gear remains controlled throughout the transition, addressing the reliability concern while preserving the simplified single-motor drive system.
2Ease of operation
If the switching gear is allowed to switch freely between positions, then the ease of operation is improved, but the manufacturing precision deteriorates as the switching gear may step out from the motor's rotation
Solution Approach 1:
The motor control unit monitors the switching gear's position and adjusts the motor's rotation speed dynamically during the switching process. This feedback control ensures that the switching gear transitions smoothly between positions while maintaining synchronization with the motor, achieving both ease of operation and rotation precision without requiring complex mechanical constraints.
3Reliability
If the motor generates large torque to switch the restrained switching gear, then the reliability of gear switching is improved, but the use of energy increases beyond what is needed for normal document reading
Solution Approach 1:
The motor operates in distinct phases: a high-torque switching phase when the switching gear needs to change positions, and a low-torque normal operation phase during document reading. The motor control unit activates large torque only periodically during switching operations, while using minimal torque during steady-state reading, thus achieving reliable gear switching without excessive continuous energy consumption.
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 configuration effectively prevents the rotation of the switching gear from stepping out from the motor's rotation, ensuring stable operation by securely separating the switching gear from the transmission gears during position switching.
Implementation Method 1
The restraint member is configured to apply, to the switching gear, a restraint force for restraining the switching of the switching gear
Implementation Method 2
the motor generates a switching torque which is larger than the moving reading torque to be generated by the motor at the time of document reading and which causes the switching gear to switch against the restraint force
Data Source
AI summary
An image reading apparatus includes a reading unit, a feeding unit, a carriage holding the reading unit, a motor, a motor-side transmission gear, a feeding unit-side transmission gear, a carriage-side transmission gear, a switching gear which switches between a meshing state of meshing with the feeding unit-side transmission gear at a feeding unit-side position and a meshing state of meshing with the carriage-side transmission gear at a carriage-side position, a restraint member which applies a restraint force for restraining the switching of the switching gear, and a motor control unit which when switching the switching gear between the carriage-side position and the feeding unit-side position, executes a large torque control of controlling the motor to generate a switching torque which is larger than a moving reading torque to be generated by the motor at a time of document reading when executing a moving reading.