Transfer Apparatus Trailing Edge Support
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Solution Overview
Problem
In electro-photographic image forming apparatuses, the rapid separation of sheets from the image carrier at the trailing edge leads to image disturbance due to electric discharge, which existing guide plates fail to adequately address.
Innovation Solution
A transfer apparatus comprising a flexible guide member and an inflexible protrusion supporting member, where the guide member is fixed to a frame at the upstream of the transfer portion and the protrusion supporting member is positioned downstream to support the trailing edge of the sheet, preventing rapid separation and ensuring stable image transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a guide plate is provided to bring the sheet to the image carrier side at the upstream portion, then electric discharge between the image carrier and sheet is suppressed, but the sheet is rapidly separated from the image carrier at the trailing edge causing image disturbance
Solution Approach 1:
The guiding structure is divided into two distinct segments: a flexible guide member for the leading portion of the sheet and an inflexible protrusion supporting member for the trailing edge. This segmentation allows each part to perform its specific function - the flexible member prevents electric discharge at the upstream while the inflexible member prevents rapid separation at the trailing edge, thereby resolving the contradiction between preventing electric discharge and maintaining image quality.
Solution Approach 2:
Different regions of the guiding structure are given different mechanical properties - the guide member is made flexible to conform to the sheet and prevent electric discharge, while the protrusion supporting member is made inflexible to rigidly support the trailing edge and prevent rapid separation. This local differentiation of material properties allows simultaneous prevention of electric discharge and trailing edge disturbance.
2Object-affected harmful factors
If the guide member is made flexible to conform to the sheet, then electric discharge is suppressed, but the trailing edge cannot be reliably supported preventing image disturbance
Solution Approach 1:
The guiding function is segmented between two members with different rigidity characteristics. The flexible guide member handles the upstream guiding to prevent electric discharge, while the inflexible protrusion supporting member handles the trailing edge support. This segmentation allows each component to optimize its performance for its specific function without compromise.
Solution Approach 2:
The inflexible protrusion supporting member acts as an intermediary element that provides reliable mechanical support for the trailing edge, complementing the flexible guide member's electric discharge prevention function. Together they form a complete guiding system where each element mediates a specific aspect of the sheet-conveyor interaction.
3Manufacturing precision
If the protrusion supporting member is positioned to support the trailing edge, then rapid separation is prevented, but the structure complexity increases
Solution Approach 1:
The guide member is designed as a thin, flexible plate that can be easily formed and attached to the guide member supporting frame. This thin-film approach minimizes the added complexity while maintaining the necessary guiding function. The simplicity of this component helps offset the added complexity of the protrusion supporting member.
Solution Approach 2:
By dividing the guiding function into two simple, dedicated components rather than one complex mechanism, the overall system complexity is managed. Each component has a single, well-defined function, making them easier to manufacture and assemble than a monolithic complex guiding structure would be.
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
Effectively suppresses image disturbance near the trailing edge of the sheet by reliably supporting it with the protrusion member, even for thicker sheets, thereby maintaining image quality.
Implementation Method 1
a transfer roller applied with a transfer bias for electrostatically attracting the developer image from the image carrier
Implementation Method 2
a inflexible protrusion supporting member which has a rigid shape as seen in a side sectional view, and is provided on the guide-member supporting frame
Data Source
AI summary
A transfer apparatus includes a transfer roller which transfers developer on an image carrier onto a conveyed recording medium at a transferring portion, a supporting frame, a flexible guide member attached to the supporting frame to guide the record medium to the transferring portion, and a inflexible protrusion supporting member which is provided on the supporting frame between the transferring portion and the guide member and protrudes to support a trailing edge of the record medium after passing the guide member. The guide member includes a swing portion which is provided at one end side at a downstream thereof. The protrusion supporting member is provided to abut the guide member while the guide member does not protrude from the protrusion supporting member to a side of the transferring portion when the swing portion of the guide member swings by abutting the record medium.