Segmented Powder Conveying Passages for Clog-Free Toner Supply

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Solution Overview

Problem

Existing powder conveying devices in image forming apparatuses face issues with toner clogging and inconsistent toner supply due to differences in conveyance speeds and cross-sectional areas of conveyance passages, leading to potential failures in toner delivery.

Innovation Solution

The design includes a first conveyor in a larger cross-sectional area conveyance passage followed by a second conveyor with a smaller cross-sectional area, allowing toner to fall by gravity between passages, ensuring consistent toner flow without clogging, even when conveyance speeds differ.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cross-sectional area of the first conveyance passage is made larger than the second conveyance passage, then toner flow stability is improved and clogging is prevented, but the device complexity increases due to the need for multiple conveyance passages with different cross-sectional areas

Engineering Contradiction:
Improvetoner supply stabilityVSAvoidconveyance passage structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conveyance system is divided into multiple segments (first and second conveyance passages) with different cross-sectional areas. The first passage has a larger cross-section for stable toner flow, while the second has a smaller cross-section. This segmentation allows each passage to be optimized for its specific function, preventing clogging while maintaining supply stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-dimensional conveyance path to a multi-dimensional system with vertical stacking of conveyance passages. The first conveyance passage is positioned above the second, creating a three-dimensional arrangement that allows different cross-sectional areas while maintaining compact device footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If conveyance speeds of the first and second conveyors are made different, then adaptability to various toner supply requirements is improved, but toner clogging occurs due to speed mismatch between passages

Engineering Contradiction:
Improveconveyance speed adjustmentVSAvoidtoner flow continuity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The conveyors are designed with variable speed capabilities, allowing dynamic adjustment of conveyance speeds. The first conveyor can operate at a higher speed while the second operates at a lower speed, with the larger cross-sectional area of the first passage compensating for the speed difference to maintain consistent toner flow and prevent clogging.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameter of cross-sectional area to compensate for differences in conveyance speed. By making the first passage's cross-sectional area larger, the system allows different conveyor speeds while maintaining equivalent toner throughput, enabling speed adaptation without causing clogging.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single conveyance passage is used, then the device complexity is reduced, but toner clogging occurs due to insufficient space for consistent toner flow

Engineering Contradiction:
Improveconveyance passage structureVSAvoidtoner delivery consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Instead of using a single conveyance passage, the system is segmented into multiple passages with different cross-sectional areas. The first passage has a larger cross-section that provides sufficient space for consistent toner flow, preventing clogging while maintaining relatively simple device structure through the segmentation approach.

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 configuration stabilizes toner supply by preventing clogging and ensuring efficient delivery from the toner container to the developing device, enhancing layout flexibility and reducing failures.

Implementation Method 1

The powder output from an outlet port of the first conveyance passage is to fall in the fall passage

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4202556B1Powder conveying device and image forming apparatus incorporating same
Publication Date: 2025.11.05 RICOH CO LTD
  • EP4202556B1 patent drawingFigure 1
  • EP4202556B1 patent drawingFigure 2~3
  • EP4202556B1 patent drawingFigure 4

AI summary

A powder conveying device (90) includes a first conveyor (71), a first conveyance passage (91), a fall passage (93), a second conveyor (72), and a second conveyance passage (92). The first conveyor (71) conveys powder in a substantially horizontal direction and is disposed in the first conveyance passage (91). The powder output from an outlet port (91b) of the first conveyance passage (91) is to fall in the fall passage (93). The second conveyor (72) conveys the powder in the substantially horizontal direction and is disposed in the second conveyance passage (92). When viewed in a cross section orthogonal to a powder conveyance direction, a cross-sectional area of a space that is not occupied by the first conveyor (71) in the first conveyance passage (91) is larger than a cross-sectional area of a space that is not occupied by the second conveyor (72) in the second conveyance passage (92).