Image Developing Device Toner Detection with Dual Conveyance Path

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Solution Overview

Problem

Existing image developing devices face challenges in accurately detecting the residual amount of toner with low fluidity, leading to image blurring or clogging due to uneven toner surfaces and incorrect detection, especially in downsized devices where conventional detection methods are not suitable for low fluidity toners.

Innovation Solution

The image developing device incorporates a dual conveyance path system with a partition member and an optical detection unit in the second conveyance path, where the developer accumulates and forms a slanted surface, allowing for accurate detection even with low fluidity toners, preventing blurring and clogging by ensuring the toner surface is formed at a suitable position for detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an outer additive agent including a lubricant component is added to toner to reduce surface wear, then the photosensitive body surface wear is suppressed, but the fluidity of the toner is reduced and the surface of the toner becomes uneven

Engineering Contradiction:
Improvesurface wear suppressionVSAvoidtoner surface uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical state parameters of the toner by controlling its temperature. By heating the toner to a temperature above its glass transition temperature, the toner's viscosity decreases and its fluidity increases, allowing it to form a uniform surface despite the presence of lubricant additives. This parameter change resolves the contradiction between wear suppression and surface uniformity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a residual amount detection unit optically detects the surface of the developer to determine toner quantity, then the remaining amount of developer can be detected, but the detection accuracy varies when the fluidity of the toner is reduced

Engineering Contradiction:
Improvedeveloper amount detectionVSAvoiddetection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the temperature parameter of the toner to above its glass transition temperature, which increases the toner's fluidity. This allows the toner surface to become smooth and uniform, enabling the optical detection unit to accurately detect the toner level without interference from surface unevenness. The parameter change directly improves detection accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by pre-heating the toner before detection to ensure it has sufficient fluidity. This preliminary temperature adjustment creates optimal conditions for accurate optical detection, preventing detection errors before they occur.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the developer conveyance path is extended to continuously supply toner, then the toner supply is stabilized, but the device size increases and is not suitable for downsizing

Engineering Contradiction:
Improvetoner supply stabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent changes the temperature parameter of the toner to increase its fluidity, which allows for more efficient toner conveyance. This improved fluidity enables compact conveyance mechanisms that can stabilize toner supply without requiring extended conveyance paths, thus maintaining small device size while achieving reliable toner supply.

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

This configuration enables precise detection of the toner amount, maintaining high image quality and preventing erroneous detections, while reducing the required toner amount and device size, thus achieving cost reduction and stability for long-term operation.

Implementation Method 1

a developer amount detection unit which includes an optical detection unit arranged in the second conveyance path and which optically detects an amount of the developer

Methodology Applied
Scientific EffectOptical detection: Absorption Spectroscopy

Data Source

PatentEP2569672B1Image developing device, process cartridge including image developing device, and image forming device including image developing device
Publication Date: 2019.05.08 RICOH CO LTD
  • EP2569672B1 patent drawingFigure 1
  • EP2569672B1 patent drawingFigure 2
  • EP2569672B1 patent drawingFigure 3

AI summary

An image developing device includes a developer supporting body; a first conveyance path in which a first conveyance member is arranged; a second conveyance path in which a second conveyance member is arranged; and a partition member that partitions the first conveyance path and the second conveyance path and that has a first communication port and a second communication port. The first communication path and the second communication path communicates with each other through the first communication port and the second communication port. The image developing device includes a developer amount detection unit that includes an optical detection unit arranged in the second conveyance path and that optically detects an amount of the developer in the image forming device. The developer is caused to accumulate in the vicinity of the developer amount detection unit.