Developer Supply Channel Geometry for Reverse Gas Flow Relief

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Solution Overview

Problem

Gas flow through the developer channel in image forming apparatuses is hindered due to variations in sectional area and developer density, leading to inefficient discharge and potential filter soiling.

Innovation Solution

The developer channel is designed with a filled portion and a falling portion, where the falling portion has a larger sectional area than the filled portion, and the transporters in these sections have varying pitch and dimensions to facilitate gas flow and developer movement, with a space between them allowing smoother passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the developer channel has a uniform sectional area, then the structure is simple, but gas flow is hindered due to developer density

Engineering Contradiction:
Improvedeveloper channel structureVSAvoidgas flow efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The developer channel is segmented into a filled portion and a falling portion with different sectional areas. The filled portion has a smaller sectional area where developer is densely packed, while the falling portion has a larger sectional area that facilitates gas flow and developer discharge, resolving the contradiction between structural simplicity and gas flow efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the developer channel are given different local qualities: the filled portion maintains a compact structure for efficient developer storage and transport, while the falling portion expands to provide adequate space for gas circulation and smooth developer flow, allowing each section to optimize its function

Inventive Principle:
Principle #3Local quality

2Reliability

If the sectional area of the developer channel is increased, then gas flow is facilitated, but the device size increases

Engineering Contradiction:
Improvegas flow efficiencyVSAvoiddeveloper channel volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

Instead of uniformly increasing the channel volume, the design segments the channel into portions with different sectional areas. The falling portion locally expands to facilitate gas flow while the filled portion maintains a compact size, achieving improved gas flow without proportionally increasing overall device volume

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sectional area parameter of the developer channel is changed along its length, transitioning from a smaller area in the filled portion to a larger area in the falling portion. This parameter variation optimizes gas flow characteristics without requiring the entire channel to have a large cross-section

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the transporters have high transport ability, then developer supply is efficient, but gas flow is restricted

Engineering Contradiction:
Improvedeveloper transport efficiencyVSAvoidgas flow through channel
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The transport system is segmented into an upstream transporter in the filled portion and a downstream transporter in the falling portion. The downstream transporter operates in a region with larger sectional area that is less restrictive to gas flow, allowing high transport ability without severely restricting gas circulation

Inventive Principle:
Principle #1Segmentation

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 enhances gas flow through the developer channel, reducing pressure buildup and minimizing filter soiling, ensuring stable developer supply and prolonging filter life.

Implementation Method 1

a downstream transporter configured to transport the developer having passed through the filled portion toward the falling portion is provided on the downstream side of the filled portion

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

each of the upstream transporter and the downstream transporter is configured to transport the developer by pushing the developer using helical pushers provided around a rotation shaft along the developer channel

Methodology Applied
Scientific EffectScrew: Screw

Implementation Method 3

a falling portion where the developer falls downward

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4657172A1Image forming apparatus
Publication Date: 2025.12.03 FUJIFILM BUSINESS INNOVATION CORP
  • EP4657172A1 patent drawingFigure 1
  • EP4657172A1 patent drawingFigure 2
  • EP4657172A1 patent drawingFigure 3

AI summary

An image forming apparatus includes: an image carrier; a developing device configured to cause a developer to adhere to the image carrier; and a supply device having a developer channel through which the developer passes, and configured to supply the developer to the developing device. The developer channel includes a filled portion that is filled with the developer over an entire cross section of the developer channel, and a falling portion where the developer falls downward. The falling portion is positioned on a downstream side of the filled portion in a developer movement direction. Gas flowing from the developing device to the supply device moves upstream in the developer movement direction through the developer channel. A sectional area of the falling portion is larger than a sectional area of the filled portion.