Development Cartridge Lateral Sealing Member Toner Leakage

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Solution Overview

Problem

The existing development cartridges in electrophotographic image forming apparatuses face challenges in preventing toner leakage, which contaminates the interior of the apparatus and requires complex sealing structures to ensure effective containment of waste toner and toner discharge during the printing process.

Innovation Solution

The development cartridge incorporates a sealing structure with a first lateral sealing member attached to the development frame, featuring a double-sided tape layer with slits and a support layer, along with a second lateral sealing member to prevent toner leakage through the end portion of the developing roller, utilizing a combination of adhesive layers and elastic materials to ensure secure attachment and effective sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing structure is added to prevent toner leakage, then toner containment is improved, but device complexity increases

Engineering Contradiction:
Improvetoner containmentVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing member is divided into multiple functional layers: a base sealing layer, an elastic deformation layer with protrusions, and an adhesive layer. This segmentation allows each layer to perform its specific function (sealing, deformation compensation, attachment) while simplifying the overall design compared to a monolithic complex seal.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastic deformation layer includes protrusions at specific locations that can locally deform to accommodate variations in the gap between sealing surfaces. This local quality enhancement allows the seal to adapt to dimensional variations without requiring a completely redesigned complex sealing structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If the sealing structure is made more complex to ensure effective containment, then toner leakage prevention is improved, but manufacturing difficulty increases

Engineering Contradiction:
Improvesealing effectivenessVSAvoidsealing structure manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The elastic deformation layer with protrusions is pre-formed during manufacturing to anticipate and compensate for dimensional variations that may occur during assembly. This preliminary action ensures sealing effectiveness without requiring complex post-assembly adjustments or highly precise manufacturing tolerances.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The protrusions in the elastic deformation layer can change their shape and position parameters through elastic deformation to adapt to variations in gap dimensions. This parameter change capability allows a relatively simple manufactured structure to achieve complex sealing adaptability.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If adhesive layers are applied to seal the end portion of the developing roller, then sealing coverage is improved, but attachment reliability decreases due to interference with the side wall

Engineering Contradiction:
Improvesealing coverage areaVSAvoidattachment reliability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The protrusions are extracted from the adhesive layer and placed in a separate elastic deformation layer. This extraction prevents the adhesive from being applied to the side wall area, maintaining attachment reliability while the protrusions provide additional sealing coverage by deforming into the gap space.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The elastic deformation layer acts as an intermediary between the adhesive layer and the gap space. It allows the adhesive to be applied only to appropriate surfaces while the protrusions mediate the sealing function in the gap area through elastic deformation, preventing adhesive interference with the side wall.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances the sealing safety of the development cartridge, preventing toner leakage and improving the stability of the sealing structure, thereby maintaining a clean and efficient printing environment.

Implementation Method 1

a support layer between the body and the double-sided tape layer and having ductility

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a double-sided tape layer to attach the body to the development frame

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3709093B1Development cartridge having sealing member
Publication Date: 2024.04.24 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3709093B1 patent drawingFigure 1
  • EP3709093B1 patent drawingFigure 2
  • EP3709093B1 patent drawingFigure 3

AI summary

Disclosed is a development cartridge detachable from a main body of an image forming apparatus. The development cartridge includes a lateral waste toner sealing member contacting an end portion of a photosensitive drum in a lengthwise direction of the photosensitive drum to prevent a waste toner from leaking through the end portion of the photosensitive drum, and a photosensitive frame including a waste toner container to contain the waste toner, a first attachment surface, to which the lateral waste toner sealing member is attached, and a side wall to form a boundary at an upstream side of the first attachment surface with respect to a rotation direction of the photosensitive drum. The lateral waste toner sealing member includes an opposite surface facing the side wall, and a protrusion protruding towards the side wall is provided on the opposite surface.