Developing Unit Discharge Paths for Variable-Fluidity Toner Control

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Solution Overview

Problem

Existing developing devices face instability in developer amounts due to differences in fluidity, leading to insufficient or excessive discharge, as structures for surplus discharge are uniform across different developers.

Innovation Solution

The image forming apparatus is designed with multiple developing devices that accommodate developers of varying fluidities, featuring tailored transport paths, connection portions, and discharge paths to stabilize developer amounts by adjusting path widths, heights, and transport member configurations based on fluidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uniform structures for discharge of surplus developers are used across all developing devices, then device complexity is reduced and ease of manufacture is improved, but the amounts of developers accommodated become unstable due to differences in fluidity

Engineering Contradiction:
Improveease of manufactureVSAvoidstability of developer amount
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by configuring discharge paths, discharge transport members, first transport paths, and first connection portions differently according to the fluidity characteristics of each developer type. Each developing device has locally optimized structures tailored to its specific developer's fluidity, ensuring stable developer amounts while maintaining manufacturing feasibility through modular design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the discharge system including path widths, path heights, and transport member configurations based on developer fluidity. By adjusting these parameters, the discharge characteristics are optimized for each developer type, resolving the contradiction between uniform manufacturing and stable developer management.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If discharge paths and transport members are customized for each developer fluidity, then stability of developer amount is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvestability of developer amountVSAvoidcomplexity of discharge structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The discharge system is segmented into distinct components: discharge paths, discharge transport members, first transport paths, and first connection portions. This segmentation allows each component to be independently optimized for different developer fluidities while maintaining overall system functionality, reducing the complexity burden of customization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs the discharge system with universal principles that can be applied across multiple developing devices. The modular configuration of discharge paths and transport members allows the same basic structure to be adapted to different fluidity requirements through parameter adjustment rather than complete redesign, reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4647850A1Image forming apparatus and developing device
Publication Date: 2025.11.12 FUJIFILM BUSINESS INNOVATION CORP
  • EP4647850A1 patent drawingFigure 1
  • EP4647850A1 patent drawingFigure 2
  • EP4647850A1 patent drawingFigure 3

AI summary

An image forming apparatus (100) includes plural image holding bodies (11) and plural developing devices (14) that respectively develop images on the image holding bodies by using developers that are different from each other in fluidity, in which each of the developing devices includes an accommodation portion (300) that accommodates a developer and that includes a first transport path (191) extending in one direction, a second transport path (192) disposed below the first transport path and extending in the one direction, a first connection portion (196) connecting one end of the first transport path and one end of the second transport path to each other, and a second connection portion (197) connecting the other end of the first transport path and the other end of the second transport path to each other, a first transport member (410) that is disposed in the first transport path and that transports the developer from one end to the other end in the one direction, a second transport member (420) that is disposed in the second transport path and that transports the developer from the other end to the one end in the one direction, a discharge path (195) that extends in the one direction from the one end of the first transport path and through which the developer flowing out from the first transport path is discharged to an outside of the accommodation portion, and a discharge transport member (450) that is disposed in the discharge path and that transports the developer flowing out from the first transport path, and the lower a fluidity of the developer to be accommodated in the accommodation portion is, the more the discharge path, the discharge transport member, the first transport path of the accommodation portion, or the first connection portion is shaped to facilitate discharge of the developer to the outside of the accommodation portion.