ADF Hinge Mechanism for Parallel Alignment of Thick Documents
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Solution Overview
Problem
Existing document reading apparatuses face issues with maintaining parallelism and compactness of the hinge mechanism due to the use of lightweight materials, which can lead to bending and require frequent adjustments, especially when handling thick documents.
Innovation Solution
A hinge mechanism design with multiple members and springs that apply torque to maintain parallelism and compactness, including a first and second urging portion with springs to manage the opening and closing of the document conveyance unit, ensuring consistent alignment with the image reading unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lightweight materials (resin or thin metal) are used to reduce the weight and cost of the ADF, then the weight and cost are reduced, but the stiffness of the ADF decreases causing the edge portion to bend down and abut on the image reading unit
Solution Approach 1:
The patent introduces a second spring (equalization spring) that applies a counteracting force to the bending moment caused by the ADF's self-weight. This spring provides an upward urging force on the back portion of the ADF, counterbalancing the downward bending force and maintaining parallelism between the ADF and document reading unit.
Solution Approach 2:
The patent modifies the mechanical parameters of the hinge mechanism by adding a second spring with specific urging force characteristics. This changes the force balance parameters of the system, allowing lightweight materials to be used while maintaining the required stiffness and parallelism through controlled elastic forces.
2Ease of operation
If springs are used to apply large torque against the self-weight of the ADF to improve operability, then the operability for opening and closing is increased, but the torque produces a lifting force on the back portion of the ADF that prevents maintaining parallelism
Solution Approach 1:
The patent divides the torque application function into two separate springs with distinct roles: the first spring (open/close spring) provides the primary torque for opening and closing operations, while the second spring (equalization spring) specifically manages the parallelism and positioning of the ADF. This segmentation allows each spring to be optimized for its specific function without interference.
Solution Approach 2:
The patent applies different spring characteristics to different regions of the hinge mechanism. The first spring is positioned and configured to maximize open/close torque, while the second spring is positioned to specifically control the back portion of the ADF and maintain parallelism. Each spring has localized quality tailored to its specific function.
3Manufacturing precision
If adjustment screws are provided to adjust parallelism, then the parallelism can be adjusted, but the adjustment is required every time the ADF deforms due to aging or temperature changes
Solution Approach 1:
The patent implements a self-adjusting mechanism where the second spring automatically compensates for deformations caused by aging or temperature changes. The spring's elastic properties allow it to continuously maintain the correct parallelism without requiring manual intervention, making the system self-regulating rather than requiring periodic adjustment.
Solution Approach 2:
The patent transitions from a static adjustment mechanism (screws that require periodic manual adjustment) to a dynamic self-adjusting mechanism. The second spring provides continuous, adaptive force that automatically compensates for changes in the ADF's dimensions or shape due to environmental factors or aging, maintaining parallelism dynamically throughout operation.
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 mechanism maintains parallelism and compactness, reducing the need for frequent adjustments and preventing bending, while allowing smooth operation and handling of thick documents.
Implementation Method 1
springs (54, 55) that apply a large torque, against the self-weight of the ADF, in a direction in which the ADF is opened
Implementation Method 2
a fixed-end member (33) pivots on a fulcrum (f1) with respect to the fixed-end member (32), so that the whole of an ADF is opened and closed
Data Source
AI summary
A document reading apparatus includes an image reading unit, a document conveyance unit, and a hinge mechanism. The document conveyance unit includes a first abutment portion and a second abutment portion. The document conveyance unit includes a first abutment portion and a second abutment portion. The hinge mechanism includes a first member, a first shaft, a second member, a second shaft, a third member, a third shaft, a fourth member, a first urging portion, a second urging portion. The fourth member has a first pair of side plates supported by the third shaft. The second spring is disposed outside the first pair of side plates in an axial direction of the third shaft.