Printer Door Hinge Structure to Prevent Warping and Rattling
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Solution Overview
Problem
In electrophotographic image forming apparatuses, such as laser printers, the door member warps due to the deviation of lock and hinge mechanisms, causing rattling and dimensional issues when trying to absorb dimensional variations between the door and main body members.
Innovation Solution
The implementation of hinge mechanisms with a first hinge hole smaller than the second hinge hole, where the hinge shaft is pressed by a spring unit against the inner surfaces, allowing for effective absorption of dimensional variations while restricting displacement and reducing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hinge holes are made larger than the hinge shaft to absorb dimensional variation, then the door member can be reliably locked and the hinge shaft can easily slide, but the door member rattles due to rattling of the hinge mechanisms
Solution Approach 1:
The patent introduces a spring mechanism that changes the dimensional parameters of the hinge system dynamically. The spring applies elastic force to press the hinge shaft against the inner peripheral surface of the hinge hole, eliminating gaps and rattling while maintaining the larger hole size for dimensional variation absorption.
Solution Approach 2:
The spring mechanism provides beforehand cushioning by pre-compressing the hinge shaft against the hinge hole surface. This elastic cushioning force compensates for dimensional variations and prevents rattling before it occurs during door operation.
2Object-affected harmful factors
If springs are added to press the hinge shaft against the inner peripheral surfaces of the hinge holes to reduce rattling, then rattling is reduced, but the door member warps due to bending moment from deviated lock and hinge mechanisms
Solution Approach 1:
The patent modifies the hinge hole dimensions (making them asymmetric with different diameters) to change the mechanical parameters of the system. This allows the spring force to be applied optimally while restricting door member displacement to prevent warping.
Solution Approach 2:
The patent applies local quality by making the hinge holes asymmetric (different diameters at different positions). This local variation in hole size allows differential restriction of door movement, preventing warping while maintaining rattling reduction.
3Adaptability or versatility
If the lock mechanism and hinge mechanism are arranged deviated from each other to accommodate layout requirements, then other equipment can be laid out properly, but a bending moment is applied to the door member causing warping
Solution Approach 1:
The patent changes the dimensional parameters of the hinge holes (making them asymmetric with different diameters) to compensate for the bending moment caused by the deviated arrangement of lock and hinge mechanisms. This allows maintained layout flexibility while preventing warping.
4Shape
If the first hinge hole is made smaller than the second hinge hole to restrict door member displacement and suppress warping, then warping is suppressed, but the ability to absorb dimensional variation is reduced
Solution Approach 1:
The patent applies local quality by creating asymmetric hinge holes with different diameters at different positions. The larger second hinge hole absorbs dimensional variations, while the smaller first hinge hole restricts door displacement and prevents warping, achieving both functions through localized dimensional differences.
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 solution effectively suppresses warping of the door member while maintaining cost-effectiveness and avoiding the need for increased rigidity, thus reducing manufacturing costs and improving the door's stability.
Implementation Method 1
a spring unit which presses the hinge shaft against inner peripheral surfaces of the first and second hinge holes
Data Source
AI summary
An image forming apparatus comprising: an image forming unit; a main body member; a door member for opening and closing an opening provided in the main body member; a hinge mechanism which joins the door member swingably with respect to the main body member; and a lock mechanism which is provided at a position deviated from the hinge mechanism, wherein the hinge mechanism includes; a first hinge hole and a second hinge hole which are provided in at least one of the door member and the main body member, and are arranged substantially coaxially while being spaced from each other, a hinge shaft inserted across the first hinge hole and the second hinge hole, and a spring unit which presses the hinge shaft against inner peripheral surfaces of the first and second hinge holes, and furthermore, the first hinge hole is smaller in size than the second hinge hole.