Developing Device Toner Mixing Control Valve

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Solution Overview

Problem

Conventional single-component developing methods, particularly nonmagnetic single-component developers, face challenges in stabilizing toner chargeability and flowability over long periods, leading to issues with image quality and reliability in electrostatic copying processes.

Innovation Solution

A developing device with a toner cartridge and a control valve system that allows for controlled toner supply and mixing, maintaining a stable ratio of fresh and deteriorated toner to ensure consistent chargeability and flowability, featuring a space-forming unit within the toner cartridge to prevent toner degradation and improve adherence to the image carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If single-component developer is used to make the developing device compact, then device size is reduced, but toner chargeability and flowability deteriorate over time

Engineering Contradiction:
Improvedeveloping device sizeVSAvoidtoner chargeability stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The developing device is divided into two separate chambers: a first chamber for storing fresh toner and a second chamber for storing deteriorated toner. This segmentation allows the system to maintain a supply of high-quality toner while managing deteriorated toner separately, thus preserving chargeability and flowability over extended operation periods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system automatically discards deteriorated toner from the first chamber to the second chamber when a predetermined amount is reached, and recovers usable toner by maintaining a continuous supply of fresh toner. This process ensures that only high-quality toner is used for image formation, maintaining reliability over time.

Inventive Principle:
Principle #34Discarding and recovering

2Device complexity

If single-component developer is used to reduce device complexity, then structure is simplified, but toner flowability decreases

Engineering Contradiction:
Improvedeveloper composition complexityVSAvoidtoner flowability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system dynamically monitors the amount of toner in the first chamber and automatically transfers deteriorated toner to the second chamber when thresholds are reached. This dynamic management ensures continuous flowability by preventing accumulation of deteriorated toner that would otherwise clog the system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A toner amount detecting unit acts as an intermediary between the two chambers, monitoring toner levels and triggering automatic transfer operations. This intermediary mechanism maintains optimal toner flowability without requiring complex manual intervention or additional mechanical components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If toner is supplied continuously to the developing unit, then productivity is improved, but toner density decreases due to consumption

Engineering Contradiction:
Improveimage formation speedVSAvoidtoner density
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The system performs preliminary separation of deteriorated toner before it significantly degrades image quality. By automatically transferring toner when predetermined amounts are reached, the system maintains high toner density in the active chamber, ensuring consistent image density and quality throughout extended operation periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The toner amount detecting unit provides continuous feedback on toner levels in the first chamber, enabling the system to automatically adjust when to transfer deteriorated toner. This feedback mechanism ensures optimal toner density is maintained in the image-forming chamber, balancing productivity with image quality.

Inventive Principle:
Principle #23Feedback

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 maintains high-quality image production over extended periods by stabilizing toner chargeability and flowability, preventing decreases in image density and adherence, thus enhancing the reliability of the electrostatic copying process.

Implementation Method 1

the developing sleeve holds the toner by static electricity

Methodology Applied
Scientific EffectStatic electricity: Electrostatics

Implementation Method 2

the toner contacts friction-charged members such as the developing sleeve or the layer thickness restricting member

Methodology Applied
Scientific EffectFriction charging: Triboelectric Effect

Data Source

PatentEP1875314B1Developing device, process cartridge, and image forming apparatus
Publication Date: 2015.01.14 RICOH CO LTD
  • EP1875314B1 patent drawingFigure 1A~1B
  • EP1875314B1 patent drawingFigure 2
  • EP1875314B1 patent drawingFigure 3(1)~3(5)

AI summary

A developing unit develops a latent image on an image carrier with toner. A toner cartridge is detachably arranged in parallel with the developing unit, and supplies the toner to the developing unit. An opening is disposed between the developing unit and the toner cartridge, through which the toner passes. The toner cartridge includes a space forming unit that forms a space in the toner stored in the toner cartridge. The space allows the toner to flow into from the developing unit.