Sheet Feeder Projections for Misfeed Prevention
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Solution Overview
Problem
Existing sheet feeder systems for image forming apparatuses face challenges in reducing costs and size while maintaining high-quality sheet feed and separation performance, particularly with the separation pad feeding system which can lead to misfeed and leading edge folds due to complex component alignment and friction coefficient mismatches.
Innovation Solution
The sheet feeder incorporates a rotary body with a friction body forming a separation nip region, supported by a receiver with projections at axial ends that guide the sheet toward the separation nip, ensuring proper alignment and reducing frictional load, thus preventing misfeed and leading edge folds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a separation pad feeding system is used to reduce costs and size, then device complexity and cost are reduced, but misfeed and leading edge folds occur due to friction coefficient mismatches and alignment issues
Solution Approach 1:
The friction body is provided with a specific friction coefficient that differs from both the rotary body and the sheet, creating a localized friction gradient. This local quality differentiation ensures that the friction body can effectively grip the sheet for separation while preventing misfeed and leading edge folds, resolving the reliability issue without increasing overall device complexity.
Solution Approach 2:
The multiple projections guide the sheet to contact the friction body at a predetermined position before the sheet reaches the separation nip region. This preliminary action ensures proper sheet alignment and positioning, preventing misfeed and leading edge folds caused by misalignment, while maintaining the simplified separation pad feeding system structure.
2Device complexity
If the friction body contacts the rotary body directly without guidance, then device complexity is reduced, but misfeed occurs due to improper sheet alignment
Solution Approach 1:
The multiple projections are positioned upstream to guide the sheet to contact the friction body at a predetermined position before separation occurs. This preliminary guidance action ensures accurate sheet positioning and alignment without requiring complex alignment mechanisms, achieving manufacturing precision through simple geometric guidance.
Solution Approach 2:
The friction body acts as an intermediary element between the rotary body and the sheet. The multiple projections guide the sheet to this intermediary friction body, which then mediates the contact and separation process. This intermediary structure simplifies the overall alignment requirements while maintaining positioning accuracy.
3Productivity
If the friction coefficient of the separation pad is too low, then sheet separation is achieved, but leading edge folds occur due to insufficient friction grip
Solution Approach 1:
The friction body is provided with a specific friction coefficient that is higher than that of the separation pad alone, creating a localized high-friction zone. This local quality enhancement provides sufficient friction grip to prevent leading edge folds while maintaining effective sheet separation, resolving the contradiction between separation efficiency and sheet integrity.
Solution Approach 2:
The sheet feeding system uses a composite friction structure where the friction body (with higher friction coefficient) works in conjunction with the separation pad (with lower friction coefficient). This composite material approach combines the gripping capability of high-friction materials with the separation capability of low-friction materials, preventing leading edge folds while ensuring effective sheet separation.
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 solution effectively reduces misfeed and leading edge folds, enhances sheet conveyance stability, and maintains high-quality sheet feeding performance while simplifying component assembly and reducing costs by using a more straightforward projection-based guide system.
Implementation Method 1
The separation pad feeding system causes a sheet fed by the sheet feed roller to contact the separation pad, so that multifeed of sheets is prevented due to friction between the separation pad and the sheet
Data Source
AI summary
A sheet feeder, which can be included in an image forming apparatus, includes a rotary body to contact and feed a recording medium to a downstream side along a sheet conveying path, a friction body disposed facing and contacting the rotary body with the sheet conveying path interposed therebetween, the friction body forming a separation nip region with the rotary body, a receiver to support the friction body at a position opposite to the separation nip region, and multiple projections to guide the recording medium toward the separation nip region. Each of the multiple projections extends toward the rotary body at respective axial ends of the rotary body and has a top face disposed upstream from the separation nip region in a sheet conveying direction between an outer circumferential surface of the rotary body and a surface of the friction body.