Developing Roller Gear Coupling for Timed Toner Supply

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Solution Overview

Problem

Existing image forming apparatuses face issues where the developing roller cannot rotate in the same direction when the coupling is rotated clockwise or counterclockwise, and toner supply is not adequately timed with the operation of the coupling.

Innovation Solution

A developing device with a developing roller, a coupling gear, and a moving gear that rotates in opposite directions to position the developing roller and an auger or agitator for timed toner supply, eliminating the need for additional components like levers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a lever mechanism is added to supply toner, then toner supply timing is improved, but device complexity increases

Engineering Contradiction:
Improvetoner supply timingVSAvoiddevice complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent combines the toner supply function with the existing coupling mechanism by adding a gear that engages with the coupling's gear teeth. This allows the coupling to simultaneously drive both the developing roller and the toner supply mechanism through a single operational input, eliminating the need for separate lever mechanisms while achieving precise toner supply timing synchronized with coupling rotation.

Inventive Principle:
Principle #5Merging (Combining)

2Volume of moving object

If the coupling structure is simplified, then device size is reduced, but toner supply timing precision deteriorates

Engineering Contradiction:
Improvedevice sizeVSAvoidtoner supply timing precision
Core Design Contradiction:
Volume of moving objectVSLoss of time

Solution Approach 1:

The coupling mechanism is designed to perform multiple functions: it drives the developing roller rotation and simultaneously supplies toner at precise intervals through its gear teeth engagement. This multi-functional design eliminates the need for separate dedicated toner supply mechanisms, reducing overall device size while maintaining precise timing control through the inherent gear engagement geometry.

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

3Ease of operation

If gear teeth are added to the coupling, then toner supply control is improved, but device complexity increases

Engineering Contradiction:
Improvetoner supply controlVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The coupling's gear teeth automatically engage with the toner supply gear, creating a self-regulating mechanism where the coupling's own rotational position directly controls toner supply timing. This self-service approach eliminates the need for external control mechanisms or additional complexity, as the coupling inherently provides both the driving force and the timing control through its gear engagement.

Inventive Principle:
Principle #25Self-service

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 developing roller rotates in the same direction regardless of coupling rotation direction, and toner is supplied with precise timing, reducing device size and ensuring simultaneous development and supply.

Implementation Method 1

a coupling having a coupling gear and a moving gear. The moving gear is in mesh with the coupling gear and rotation of the coupling gear in opposite respective directions moves the moving gear to respective positions

Methodology Applied
Scientific EffectGear mechanism: Gear

Data Source

PatentEP4293427B1Developing device
Publication Date: 2026.02.25 BROTHER KOGYO KK
  • EP4293427B1 patent drawingFigure 1
  • EP4293427B1 patent drawingFigure 2
  • EP4293427B1 patent drawingFigure 3

AI summary

A developing device 10 includes an auger or an agitator that is capable of supplying toner in a toner accommodation chamber to a developing chamber and is rotatable about an auger axis extending in an axial direction, a transporting gear 26 that is rotatable together with the auger or the agitator, and a moving gear 33 that is in mesh with a coupling gear 22B and is rotatable both counterclockwise and clockwise. The moving gear 33 is movable while being in mesh with the coupling gear 22B between a first position where the moving gear 33 is in mesh with the transporting gear 26 and a second position where the moving gear 33 is out of mesh with the transporting gear 26. The moving gear 33 moves to the first position when the coupling gear 22B rotates counterclockwise and to the second position when the coupling gear 22B rotates clockwise.