Paper Feed Sensing Slider Absorbs Assembly Variations
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Solution Overview
Problem
In image formation apparatuses, the existing sensing modules using push switches for detecting paper size and presence often experience erroneous sensing due to dimensional tolerances and assembly variations, leading to unstable paper feeding and potential paper jams, especially when using commercially available push switches with small movable strokes.
Innovation Solution
The proposed solution involves a sensing module with a slider, push switch, first and second elastic bodies, and a coupling member, where the second elastic body provides a greater biasing force than the first, allowing the slider to move and absorb variations in the mounting direction, ensuring stable detection of switch depression without causing switch breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a commercially available push switch with a small movable stroke is used, then the apparatus size is reduced, but erroneous sensing occurs due to dimensional tolerances and assembly variations
Solution Approach 1:
The sensing mechanism is segmented into multiple components: a slider that moves independently, a push switch with its own movable stroke, and elastic bodies that provide biasing forces. This segmentation allows the slider to absorb dimensional tolerances and assembly variations through its extended movable stroke, while the push switch maintains its small size for compact apparatus.
Solution Approach 2:
The slider acts as an intermediary between the paper feed unit and the push switch. It translates the mounting action into a controlled depression of the push switch, absorbing variations in mounting position and force through its extended stroke and elastic biasing, thereby ensuring reliable switch activation regardless of assembly tolerances.
2Volume of moving object
If a push switch with a small movable stroke is used, then the apparatus becomes more compact, but the push switch may break due to excessive depression from assembly variations
Solution Approach 1:
The elastic bodies (first and second elastic bodies) provide beforehand cushioning by absorbing excess depression force before it reaches the push switch. The slider's extended movable stroke also cushions the impact, ensuring that the push switch is depressed within its safe stroke limits even when assembly variations cause excessive mounting force.
Solution Approach 2:
The slider serves as a protective intermediary that limits the force transmitted to the push switch. Its extended stroke and elastic biasing mechanism ensure that the push switch is depressed smoothly and within its design limits, preventing breakage while still enabling reliable sensing.
3Reliability
If the movable stroke of the slider is extended to absorb assembly variations, then sensing reliability is improved, but the device complexity increases
Solution Approach 1:
The slider performs multiple functions: it moves to absorb dimensional tolerances, transmits force to activate the push switch, and returns to its initial position through elastic biasing. The elastic bodies also serve dual purposes of providing biasing force and cushioning excessive depression. This multi-functionality reduces the need for additional components, mitigating the increase in device complexity.
Solution Approach 2:
The invention changes the parameter of the slider's movable stroke from small to extended, allowing it to absorb assembly variations. This parameter change is achieved through the interaction with elastic bodies that provide the necessary biasing force, creating a simple yet effective mechanism that improves reliability without requiring complex control systems or additional sensors.
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 allows for stable sensing of paper feed unit presence and type, preventing paper jams and switch breakage by extending the movable stroke of the slider to accommodate assembly variations, ensuring reliable operation.
Implementation Method 1
The first elastic body is a member arranged to be interposed between the slider and a portion which does not relatively move with respect to the apparatus body, for elastically biasing the slider toward a direction away from the push switch
Implementation Method 2
The second elastic body is a member arranged to be interposed between the slider and a switch portion of the push switch, for elastically biasing the slider toward a direction away from the push switch
Data Source
AI summary
An image formation apparatus includes, in an apparatus body, a sensing portion which senses presence or absence of depression by a paper feed unit. The sensing portion includes a slider provided to be slidingly movable along a mounting direction of the paper feed unit, a push switch arranged behind the slider along the mounting direction, and a first elastic body and a second elastic body for elastically biasing the slider toward a direction away from the push switch. The first elastic body is interposed between the slider and a portion which does not relatively move with respect to the apparatus body, and the second elastic body is interposed between the slider and a switch portion of the push switch.