Sheet Feeding Device Upper Contact Member Load Distribution
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Solution Overview
Problem
The existing sheet feeding devices in image forming apparatuses face increased sliding resistance and deformation of the inner rail due to the load of the sheet storage cassette, leading to higher insertion and retraction forces and reduced positioning accuracy, especially when an automatic retracting device is used.
Innovation Solution
The introduction of an upper contact member, such as an upper roller member, that moves on the outer rail when the sheet storage cassette is inserted or drawn, reduces the load transmitted to the inner rail via a positioning pin, thereby minimizing deformation and maintaining accurate positioning by distributing the load through the outer rail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the inner rail is provided with a positioning pin and the sheet storage cassette is provided with an engagement hole to position the sheet storage cassette, then the positioning accuracy is improved, but the inner rail is deformed due to the load of the sheet storage cassette, causing increased sliding resistance and reduced positioning accuracy
Solution Approach 1:
A positioning member is introduced as an intermediary element between the inner rail and the sheet storage cassette. The positioning member includes a positioning protrusion that engages with the engagement hole, while the inner rail only provides support through the outer rail, avoiding direct load transmission to the positioning pin. This mediator structure allows positioning to occur without subjecting the inner rail to excessive loads that cause deformation.
2Measurement precision
If the positioning pin is used to engage with the engagement hole, then the positioning accuracy is improved, but the sliding resistance of the slide rail is increased due to inner rail deformation, requiring larger insertion and retraction forces
Solution Approach 1:
The positioning member acts as a mediator that separates the positioning function from the load-bearing function. The positioning protrusion on the positioning member engages with the engagement hole to provide accurate positioning, while the load is transmitted through the outer rail structure rather than through the inner rail and positioning pin connection, thereby reducing sliding resistance.
3Measurement precision
If the inner rail is deformed due to load, then the positioning accuracy is decreased, but adding support structures may increase device complexity
Solution Approach 1:
The positioning member with positioning protrusion serves as a simple intermediary component that maintains positioning accuracy without requiring complex additional support structures. The solution leverages the existing outer rail structure to bear loads, and the positioning member simply provides the positioning function through its protrusion-engagement hole interface, avoiding inner rail deformation without increasing overall structural complexity.
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 decreases the sliding resistance and improves the positioning accuracy of the sheet storage cassette, allowing for smoother sheet feeding and easier manual or automatic retraction of the cassette, enhancing the overall operation of the image forming apparatus.
Implementation Method 1
the inner rail is deformed to be fallen inside. Then, a sliding resistance of the slide rail is increased
Data Source
AI summary
A sheet feeding device includes a housing, a sheet storage cassette, a slide rail and an upper contact member. The housing has a pair of inner walls facing each other. The sheet storage cassette is attached between the inner walls in an insertable and drawable manner along a first direction. The sheet storage cassette has a pair of wall parts facing the pair of inner walls. The slide rail includes an outer rail and an inner rail. The outer rail extends along the first direction on the inner wall and the inner rail extends along the first direction on the wall part. The inner rail is supported by the outer rail in a movable manner. The upper contact member is provided on the wall part and moves on an upper face of the outer rail when the sheet storage cassette is inserted and drawn with respect to the housing.