Developer Cartridge Slope Design for Toner Leakage Prevention

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Solution Overview

Problem

Existing image forming apparatuses face issues with toner leakage when the developer cartridge is detached, as toner can stay at the lower edges of the openings and leak outside during toner supply.

Innovation Solution

The developer cartridge and developing device incorporate slopes at the lower edges of their openings, inclined in a direction crossing the horizontal plane, to prevent toner leakage by ensuring toner flows inward and does not accumulate at the edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the developer cartridge is detachably attached to the developing device with openings for toner supply, then the ease of operation is improved, but toner leakage occurs at the lower edges of the openings

Engineering Contradiction:

Improvedetachable attachmentVSAvoidtoner leakage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by modifying only the lower edge region of the opening with a slope structure, while keeping the rest of the opening and cartridge design unchanged. This localized modification prevents toner leakage at the critical lower edge area without affecting the overall detachable attachment functionality or requiring redesign of the entire opening structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of trying to contain toner with vertical or inward-facing structures at the lower edge, the patent inverts the approach by creating an outward-sloping surface that actively directs toner away from the leakage-prone lower edge and back into the cartridge interior, using gravity and the slope geometry to reverse the problematic toner flow direction.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If openings are provided for toner communication between cartridge and device, then the productivity is improved, but toner accumulates at the lower edges of the openings

Engineering Contradiction:

Improvetoner supply efficiencyVSAvoidtoner accumulation

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The slope structure is applied locally at the lower edge of the opening where toner accumulation occurs, creating a specific geometric feature that redirects toner flow. This localized intervention prevents accumulation at the critical area while maintaining the overall opening structure necessary for efficient toner supply between the cartridge and developing device.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the typical opening edge configuration by sloping the lower edge outward instead of keeping it vertical or inward-facing. This inverted geometry prevents toner from accumulating at the lower edge by directing it back into the cartridge, thereby eliminating the accumulation problem while preserving the opening's function for productive toner supply.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If the opening edges are horizontal for stable structure, then the ease of manufacture is improved, but toner leakage and accumulation occur

Engineering Contradiction:

Improvehorizontal opening edgeVSAvoidtoner containment

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent maintains the easy-to-manufacture horizontal upper opening edge while applying the slope modification only at the lower edge region. This localized quality change preserves the manufacturing simplicity of the majority of the opening structure while addressing the toner containment issue specifically where it occurs, achieving both ease of manufacture and reliable toner containment.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of maintaining a purely horizontal lower edge that causes toner leakage, the patent inverts the edge orientation by creating an outward slope. This inverted geometry at the lower edge actively prevents toner leakage and accumulation, improving reliability while requiring minimal deviation from the otherwise simple horizontal opening structure that is easy to manufacture.

Inventive Principle:

Principle #13The other way round (Inversion)

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 design effectively prevents toner leakage by ensuring toner is carried inside the device, maintaining reliable operation and reducing maintenance needs.

Implementation Method 1

a slope provided at a lower edge of the cartridge-side opening, the slope inclining in a direction crossing a horizontal direction

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS7907875B2Developer cartridge and developing device

Publication Date: 2011.03.15 BROTHER KOGYO KK

AI summary

A developer cartridge includes a cartridge cabinet configured to accommodate developer. The cartridge cabinet includes a cartridge-side opening that allows communication between an inside of the cartridge cabinet and an outside of the cartridge cabinet, and a slope provided at a lower edge of the cartridge-side opening, the slope inclining in a direction crossing a horizontal direction when the cartridge-side opening is oriented in a horizontal direction.