Developing Roller Recirculation Layout to Reduce Toner Scattering

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Solution Overview

Problem

Existing image forming apparatuses face issues with developer deterioration due to stress caused by surplus developer retention on the upstream side of the developing roll, leading to inefficiencies in the reuse and distribution of toner and carrier.

Innovation Solution

The developing device incorporates a configuration that includes a discharge route and air stream mechanism to efficiently guide toner and carrier back into the supply system, reducing external scattering and maintaining internal pressure, thereby improving the reuse and distribution of developing agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If surplus developer is retained on the upstream side of the developing roll, then the developer quantity is regulated, but stress is produced in the developer causing deterioration

Engineering Contradiction:
Improvedeveloper quantityVSAvoiddeveloper quality
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts the surplus developer from the upstream side of the developing roll using a discharge route that leads to a discharge chamber. This removes the harmful retention of surplus developer that causes stress and deterioration, while still allowing the developer to be reused through the air stream mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an air stream as an intermediary medium to transport the discharged developer from the discharge chamber back to the developing roll. This intermediary mechanism allows the developer to be redistributed without direct contact with the stressed upstream region, preventing further deterioration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If a carried developer quantity regulating member is used, then developer quantity is controlled, but toner scattering occurs

Engineering Contradiction:
Improvedeveloper quantityVSAvoidtoner scattering
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent uses pneumatic principles by introducing an air stream to transport the discharged developer from the discharge chamber back to the developing roll. This pneumatic mechanism replaces mechanical contact methods, thereby preventing toner scattering that would occur with mechanical regulators.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If surplus developer is not efficiently reused, then distribution efficiency decreases, but external scattering increases

Engineering Contradiction:
Improvedeveloper reuse efficiencyVSAvoidexternal scattering
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system enables self-service by using the discharged developer itself as the material to be reused. The air stream automatically transports the surplus developer from the discharge chamber back to the developing roll, creating a closed-loop system that efficiently reuses developer without external intervention or scattering.

Inventive Principle:
Principle #25Self-service

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 effectively reduces toner scattering and maintains internal pressure, enhancing the efficiency and reliability of the developing device by reusing surplus developer and preventing excessive discharge.

Implementation Method 1

The developing device incorporates a configuration that includes a discharge route and air stream mechanism to efficiently guide toner and carrier back into the supply system

Methodology Applied
Scientific EffectAir stream: Convection

Data Source

PatentEP3776084B1Imaging system
Publication Date: 2025.11.12 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3776084B1 patent drawingFigure 1
  • EP3776084B1 patent drawingFigure 2
  • EP3776084B1 patent drawingFigure 3

AI summary

An imaging system includes a developing roller connected to a supply channel to supply a developing agent and to transfer toner in the developing agent to a photosensitive drum at a supply position, a regulation member located adjacent to the developing roller at an upstream side of the supply position to restrict a thickness of the developing agent; and a casing that forms a release chamber in the periphery of the developing roller between an upstream side of the regulation member and a downstream side of the supply position. The release chamber includes an outlet to discharge scattered toner to an inlet of the supply channel.