Layer Regulation Member Blade Free Length Variation

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Solution Overview

Problem

In image formation apparatuses using the electrophotographic method, the contact force of the layer regulation member's blade against the developer carrier tends to be reduced at the end portions, leading to unevenness in image density due to thicker toner layers.

Innovation Solution

The development unit incorporates a layer regulation member with a metal blade that has a shorter free length and greater flexural rigidity at the end portions compared to the center, supported by a frame with a holder that adjusts the blade's deflection, ensuring consistent contact force along the blade's length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the layer regulation member uses a metal blade pressed against the developer carrier, then the toner layer thickness can be regulated, but the contact force of the blade against the developer carrier is reduced at end portions, causing unevenness in image density

Engineering Contradiction:

Improvetoner layer thickness uniformityVSAvoidcontact force at end portions

Core Design Contradiction:

Manufacturing precisionVSForce

Solution Approach 1:

The blade is designed with varying free lengths along its longitudinal direction, where the free length at end portions is shorter than at the center portion. This creates local structural differences that compensate for the natural reduction in contact force at ends, maintaining uniform toner layer thickness across the entire blade width

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The blade's geometric parameter (free length) is changed along its length to optimize contact force distribution. By making the free length shorter at end portions and longer at the center, the blade's flexibility and contact pressure are adjusted locally to achieve uniform toner layer regulation across the developer carrier surface

Inventive Principle:

Principle #35Parameter changes

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 suppresses the reduction in contact force at the end portions, resulting in uniform toner layer thickness and reduced image density unevenness.

Implementation Method 1

a free length of the blade at an end portion in a longitudinal direction of the layer regulation member is shorter than a free length of the blade at a center portion in the longitudinal direction of the layer regulation member

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11619891B2Development unit, image formation unit, and image formation apparatus including developer carrier and layer regulation member

Publication Date: 2023.04.04 OKI ELECTRIC INDUSTRY CO LTD

AI summary

A development unit according to an embodiment may include a developer carrier configured to carry developer on a surface thereof; a layer regulation member being elongate in a direction and provided facing the developer carrier; and a frame supporting the developer carrier and the layer regulation member. The layer regulation member comprises a metal blade that contacts the developer carrier and a support member attached to the frame and supporting the blade. A free length of the blade at an end portion in a longitudinal direction of the layer regulation member is shorter than a free length of the blade at a center portion in the longitudinal direction of the layer regulation member.