Developing Roller Thickness Regulation Blade with Dual Roughness

Solution Overview

Problem

The existing developing devices in electro-photographic image forming apparatuses face issues with uneven developer density due to varying surface roughness of the rubber portion, leading to friction-induced local fixation of developer or additives, resulting in vertical stripes during image formation, which is difficult to resolve with precise surface roughness optimization.

Innovation Solution

A developing device with a thickness regulation blade featuring a rubber portion divided into regions with different surface roughness values, where the first region has a coarser surface roughness and the second region has a finer surface roughness, strategically positioned to minimize friction and ensure uniform developer distribution, reducing the likelihood of image formation failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the surface roughness of the contact region of the rubber portion is fine, then the thickness of the developer layer becomes substantially uniform, but the friction force increases causing developer or external additive to be locally fixed to the upstream end of the contact region

Engineering Contradiction:

Improveuniformity of developer layer thicknessVSAvoidfriction force causing local fixation of developer

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The rubber portion is divided into a first contact region with finer surface roughness and a second contact region with coarser surface roughness. The first contact region maintains uniform developer layer thickness, while the second contact region reduces friction force to prevent local fixation of developer or external additive. This local differentiation of surface quality resolves the contradiction between uniformity and friction reduction.

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If the surface roughness of the contact region of the rubber portion is coarse, then the friction force is reduced, but the thickness of the developer layer varies in the rotation axis direction of the developing roller

Engineering Contradiction:

Improvefriction force reductionVSAvoiduniformity of developer layer thickness

Core Design Contradiction:

Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The rubber portion is divided into a first contact region with finer surface roughness and a second contact region with coarser surface roughness. The first contact region maintains uniform developer layer thickness, while the second contact region reduces friction force to prevent local fixation of developer or external additive. This local differentiation of surface quality resolves the contradiction between uniformity and friction reduction.

Inventive Principle:

Principle #3Local quality

3Reliability

If the surface roughness is optimized precisely to prevent image formation failures, then image quality improves, but the production difficulty and cost increase significantly

Engineering Contradiction:

Improveimage formation success rateVSAvoidproduction difficulty of thickness regulation blade

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The rubber portion is divided into a first contact region with finer surface roughness and a second contact region with coarser surface roughness. The first contact region maintains uniform developer layer thickness, while the second contact region reduces friction force to prevent local fixation of developer or external additive. This local differentiation of surface quality resolves the contradiction between uniformity and friction reduction.

Inventive Principle:

Principle #3Local quality

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 prevents image formation failures by maintaining uniform developer thickness and reducing friction-induced issues, allowing for easier production of the thickness regulation blade without the need for highly precise surface roughness optimization.

Implementation Method 1

when the surface roughness of the contact region of the rubber portion is fine, a friction force applied from the contact region of the rubber portion to the developer increases between the developing roller and the rubber portion

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS9348257B2Developing device provided with developing roller and thickness regulation blade

Publication Date: 2016.05.24 BROTHER KOGYO KK

AI summary

In a developing device, a developing roller has an outer peripheral surface movable in a moving direction upon rotation of the developing roller to transfer developing agent to a developing region having a width in an axial direction of the developing roller. A thickness regulation blade includes a rubber portion. The rubber portion provides a contact region in contact with the outer peripheral surface to provide a nip region relative to the developing roller. The contact region includes a first region; and a second region. The first region and the second region each extends in the axial direction by a length at least equal to or greater than the width of the developing region. The first region has a first surface roughness. The second region is positioned downstream of the first region in the moving direction and has a second surface roughness finer than the first surface roughness.