Planetary Gear Switching Mechanism for Image Reading Apparatus
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Solution Overview
Problem
Existing image reading apparatuses face challenges in efficiently switching driving force transmission between document conveying and placed document reading functions without causing collisions, leading to increased costs and reduced efficiency.
Innovation Solution
The apparatus employs a planetary gear mechanism with a sun gear, planetary gear, and output gears to selectively transmit driving force to either the moving mechanism or conveyance mechanism, using a load generation part to increase rotational resistance and a meshing part to facilitate smooth gear interaction, allowing for switching without imaging unit collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single driving source is used to drive both the document conveying mechanism and the imaging unit reciprocating mechanism, then the apparatus cost is reduced, but the switching of driving force transmission becomes complex and may cause imaging unit collision
Solution Approach 1:
A one-way clutch is introduced as an intermediary element between the driving source and the two mechanisms. The one-way clutch selectively transmits driving force in different rotation directions of the common driving source to either the document conveying mechanism or the imaging unit reciprocating mechanism, enabling automatic switching without complex control mechanisms and preventing imaging unit collision.
Solution Approach 2:
The system utilizes the rotation direction of the common driving source as a dynamic control parameter. By reversing the rotation direction, the one-way clutch automatically switches which mechanism receives driving force, transforming a static switching problem into a dynamic one solved by directional control.
2Adaptability or versatility
If the imaging unit is moved to read placed documents, then the placed document reading function is enabled, but the document conveying function cannot be performed simultaneously
Solution Approach 1:
The system alternates between the two reading functions by periodically reversing the rotation direction of the common driving source. The one-way clutch automatically directs driving force to the appropriate mechanism during each phase, enabling sequential operation of both functions without requiring simultaneous power sources.
3Reliability
If the planetary gear mechanism is used to switch driving force transmission, then the switching is achieved without imaging unit collision, but the rotational resistance varies during operation
Solution Approach 1:
The load generation part utilizes the system's own operational state to automatically adjust rotational resistance. When the imaging unit is at the first position, the load generation part increases rotational resistance of the first output gear, which automatically triggers the planetary gear to switch to the second output gear, eliminating the need for external control signals.
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 enables efficient switching of driving force transmission without imaging unit collisions, improving operational efficiency and reducing costs by allowing seamless operation between conveyed and placed document reading functions.
Implementation Method 1
a planetary gear configured to rotate by being meshed with the sun gear and having a rotation center configured to revolve around the sun gear between a third position and a fourth position
Implementation Method 2
a load generation part configured to increase a rotational resistance of the first output gear when the imaging unit is located at the first position
Data Source
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AI summary
An image reading apparatus comprising: an imaging unit; a moving mechanism moving the imaging unit between a first position and a second position; a conveyance mechanism; a sun gear; a planetary gear that rotates by being meshed with the sun gear and having a rotation center configured to revolve around the sun gear; a first output gear meshed with the planetary gear and transmits a driving force to the moving mechanism; a second output gear meshed with the planetary gear and transmits a driving force to the conveyance mechanism; a load generation part increasing a rotational resistance of the first output gear when the imaging unit is located at the first position, and a meshing part being meshed with teeth of the planetary gear when the planetary gear revolves around the sun gear.