Developer Discharge Regulation Structure for Stable Image Density

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Solution Overview

Problem

Existing electro-photographic image forming devices face issues with maintaining the appropriate level of developer, leading to problems such as density unevenness, developer leakage, and toner scattering due to excessive or insufficient discharge of the developer.

Innovation Solution

The developing device incorporates a discharge regulation member that partially blocks the upper path of the developer conveying path while allowing the lower path to be open, preventing excessive discharge and ensuring the developer is maintained at an appropriate level by stagnating surplus developer on the upstream side of the discharge portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the developer discharge portion is opened to allow surplus developer to be discharged, then the developer level can be maintained, but excessive discharge occurs causing density unevenness and auger marks

Engineering Contradiction:

Improvedeveloper levelVSAvoidimage density uniformity

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The conveying path is divided into upper and lower paths by the discharge regulation member. The lower path allows developer to pass through to the discharge portion, while the upper path is blocked, creating segmented flow paths that control discharge quantity and prevent excessive discharge causing image defects

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The discharge regulation member acts as an intermediary component between the conveying member and the discharge portion. It partially blocks the conveying path to regulate the amount of developer discharged, serving as a mediator that controls the flow to maintain developer level while preventing excessive discharge

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If the discharge of surplus developer is increased to prevent developer shortage, then the developer level can be maintained, but toner scattering and insufficient charging occur

Engineering Contradiction:

Improvedeveloper levelVSAvoidtoner scattering

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

By segmenting the conveying path into upper and lower paths with the discharge regulation member, the system controls the discharge amount to be moderate rather than excessive. This prevents toner scattering and insufficient charging while still maintaining the developer level through regulated discharge

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The discharge regulation member implements partial blocking of the conveying path, allowing only a controlled portion of the developer to be discharged. This partial action prevents excessive discharge that would cause toner scattering while still maintaining adequate developer level

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12487551B2Developing device with structure to regulate discharging amount of developer

Publication Date: 2025.12.02 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

A developing device includes a conveying member to circulate a developer in a housing, a developer discharge portion extending from one end portion of the housing to form a passage through which surplus developer is discharged from the housing, and a discharge regulation member located on an upstream side of the developer discharge portion with respect to a direction in which the developer is conveyed to the developer discharge portion by the conveying member to partially block a conveying path of the developer. The discharge regulation member includes a lower end portion and an upper end portion arranged apart from a bottom and an upper wall of the conveying path, respectively.