Developing Device Filter Structure for Toner Scattering Control

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Solution Overview

Problem

Existing developing devices in image forming apparatuses face issues with toner scattering due to increased internal pressure, which conventional filters fail to adequately address.

Innovation Solution

A filter holding device with a filter having a two-layer structure, where the second side has a higher weight density and larger surface area intersecting the communication direction than the first side, is disposed in an opening portion to prevent toner scattering while allowing air ventilation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional filter is disposed in the opening portion to prevent toner scattering, then toner scattering is reduced, but the filter easily clogs and internal pressure increases

Engineering Contradiction:

Improvetoner scatteringVSAvoidfilter clogging

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The filter is divided into multiple layers with different pore sizes and density characteristics. The first layer has larger pores for initial filtration, while subsequent layers have progressively smaller pores for finer filtration, preventing clogging while maintaining toner scattering prevention

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the filter have different weight densities and pore structures. The density varies from the upstream side to the downstream side, with the upstream side having lower density for better airflow and the downstream side having higher density for effective toner particle capture

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If a conventional filter is disposed in the opening portion to prevent toner scattering, then toner scattering is reduced, but internal pressure increases

Engineering Contradiction:

Improvetoner scatteringVSAvoidinternal pressure

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The filter is divided into multiple layers with progressively smaller pores, allowing air to pass through while progressively filtering toner particles. This segmented structure reduces resistance to airflow compared to a single dense layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pore size, weight density, and surface area parameters are optimized across different layers. The gradual change in these parameters from upstream to downstream allows for progressive filtration with minimal pressure drop

Inventive Principle:

Principle #35Parameter changes

3Productivity

If a filter with larger surface area at the second side is used, then toner collection efficiency is enhanced, but device complexity increases

Engineering Contradiction:

Improvetoner collection efficiencyVSAvoidfilter structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The filter structure has varying properties at different locations: the second side has larger surface area and appropriate density for efficient toner capture, while the first side has smaller surface area and lower density for smooth airflow entry

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The filter is constructed as a composite structure with multiple layers having different pore sizes, weight densities, and surface areas. This composite approach achieves high toner collection efficiency while maintaining manufacturability

Inventive Principle:

Principle #40Composite materials

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

The filter effectively reduces internal pressure, preventing toner scattering and enhancing toner collection efficiency without clogging, ensuring stable operation of the developing device.

Implementation Method 1

The filter is disposed in the opening portion and includes a first side and a second side. The first side is located adjacent to the inside of the filter holding device. The second side is located adjacent to the outside of the filter holding device. The filter has a larger weight density per unit volume at the second side than a weight density per unit volume at the first side and has a larger area of a surface intersecting a communication direction at the second side than an area of a surface intersecting the communication direction at the first side.

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Data Source

PatentUS12508527B2Filter holding device, developing device, process cartridge, and image forming apparatus

Publication Date: 2025.12.30 RICOH CO LTD

AI summary

A filter holding device includes an opening portion and a filter. The opening portion communicates between an inside and an outside of the filter holding device. The filter is disposed in the opening portion and includes a first side and a second side. The first side is located adjacent to the inside of the filter holding device. The second side is located adjacent to the outside of the filter holding device. The filter has a larger weight density per unit volume at the second side than a weight density per unit volume at the first side and has a larger area of a surface intersecting a communication direction at the second side than an area of a surface intersecting the communication direction at the first side.