Density-Gradient Filter Holding for Toner Leak Control

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Solution Overview

Problem

Conventional filter systems in developing devices allow air to leak laterally with toner, leading to incomplete collection and scattering of toner outside the device.

Innovation Solution

A filter holding device with an opening portion and a filter disposed within, where the filter has a higher weight density on one side facing outward, ensuring air is discharged while minimizing toner leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a filter is disposed in an opening portion to discharge air and collect toner, then toner scattering is reduced, but air leaks laterally with toner causing incomplete collection

Engineering Contradiction:

Improvetoner scatteringVSAvoidfilter collection function

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The filter is designed with non-uniform weight density distribution, where the weight density at the second side (outer side) is greater than at the first side (inner side). This local quality variation ensures that the filter material is more densely packed at the discharge side, preventing lateral leakage of air and toner while maintaining effective toner collection capability.

Inventive Principle:

Principle #3Local quality

2Stress or pressure

If air is discharged through the opening portion to maintain internal pressure, then pressure control is improved, but toner is discharged together with air reducing filter effectiveness

Engineering Contradiction:

Improveinternal pressure controlVSAvoidtoner loss

Core Design Contradiction:

Stress or pressureVSLoss of substance

Solution Approach 1:

The filter's weight density parameter is changed to be non-uniform, with higher density at the second side facing the outside. This parameter change allows the filter to selectively allow air to pass through while blocking toner particles, achieving both pressure control and preventing toner loss simultaneously.

Inventive Principle:

Principle #35Parameter changes

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 solution effectively reduces toner scattering and enhances the filter's collection performance by ensuring air is discharged without carrying toner, maintaining internal pressure and preventing clogging.

Implementation Method 1

The filter has a larger weight density per unit volume at the second side than at the first side in a state in which the filter is disposed in the opening portion

Methodology Applied

Scientific EffectDensity gradient: Density Gradient

Data Source

PatentUS12533617B2Filter holding device, developing device, process cartridge, and image forming apparatus

Publication Date: 2026.01.27 RICOH CO LTD

AI summary

A filter holding device includes an opening portion and a filter. The opening portion communicates an inside of the filter holding device with an outside of the filter holding device, and has a rim that extends in a communication direction from the inside of the filter holding device toward the outside of the filter holding device. The filter is disposed in the opening portion, and has a first side and a second side. The first side faces the inside of the filter holding device. The second side faces the outside of the filter holding device. The filter has a larger weight density per unit volume at the second side facing the outside of the filter holding device than at the first side facing the inside of the filter holding device in a state in which the filter is disposed in the opening portion.