Developer Concentration Adjustment Using Stirrer Load Measurement

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing developer concentration adjustment methods face challenges in accurately measuring high concentration liquid developers due to low light transmission and sensitivity issues, and toner adhesion on stirrers affects viscosity measurements, leading to incorrect concentration adjustments.

Innovation Solution

A developer concentration adjustment apparatus that uses a stirrer load as a substitute characteristic for concentration measurement, includes a cleaning operation to remove residual toner from the stirrer, and employs a controller to adjust the developer concentration by supplying supplemental developers or carrier liquid, ensuring precise concentration adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If light transmission method is used to measure developer concentration, then measurement is simple, but sensitivity is low and detection precision deteriorates due to saturation in high concentration developers

Engineering Contradiction:

Improvesimplicity of measurement methodVSAvoidconcentration detection precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces the optical measurement system with a mechanical stirring system. Instead of using light transmission to measure concentration, the system uses a stirrer to mix the developer and measures the mechanical load (torque or power consumption) required for stirring. This mechanical approach provides better sensitivity for high concentration developers where light transmission becomes saturated.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If stirrer load is used to measure developer concentration, then measurement sensitivity improves, but toner adhesion on stirrer causes measurement errors

Engineering Contradiction:

Improveconcentration detection precisionVSAvoidmeasurement accuracy due to toner adhesion

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing a cleaning operation before the actual concentration measurement. The stirrer is rotated at a high speed to remove adhered toner from its surface, ensuring that the subsequent load measurement reflects only the developer concentration and not contamination from previous measurements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements periodic cleaning cycles where the stirrer is rotated at high speed to remove toner adhesion. This periodic maintenance action ensures that the measurement system remains reliable over extended operation periods, preventing cumulative errors from toner buildup.

Inventive Principle:

Principle #19Periodic action

3Productivity

If high concentration developer is used to reduce toner consumption, then productivity improves, but concentration control becomes difficult due to concentration changes in residual developer

Engineering Contradiction:

Improvetoner efficiencyVSAvoidconcentration control precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control system for concentration management. The stirrer load measurement provides real-time feedback on developer concentration, and based on this information, the system automatically supplements the developer with concentrated toner solution or pure carrier liquid to maintain the target concentration, enabling precise control even with high concentration developers.

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 apparatus achieves precise developer concentration adjustment by reducing toner adhesion-related errors and maintaining accurate measurements, even with high viscosity developers, thereby improving the reliability of the image forming process.

Implementation Method 1

Viscosity relatively largely varies in response to concentration change in a high concentration range. Further, since such a method for measuring viscosity of developer, a characteristic value, such as torque at the time of stirring a developer which can be measured relatively easily can be used as a substitute characteristic

Methodology Applied

Scientific EffectViscosity: Viscometer

Implementation Method 2

When adhesion of toner is generated on the stirrer for measuring the stirring load, frictional resistance between the stirrer and the liquid developer may vary and affect the measurement of the viscosity of liquid developer

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8660449B2Developer concentration adjustment apparatus, method for adjusting developer concentration, and image forming apparatus using the same

Publication Date: 2014.02.25 KONICA MINOLTA INC

AI summary

This invention provides a developer concentration adjustment apparatus, a method for concentration adjustment, and an image forming apparatus, in which concentration adjustment is performed by use of a stirring load as a substitute characteristic of viscosity which represents a developer concentration, wherein a trouble of abnormality generation in toner concentration detection due to drying-adhesion of a residual developer on the stirrer is reduced. At the time of finishing the concentration adjustment, a concentration adjustment tank is made to be empty and the stirrer is cleaned by carrier liquid or a liquid developer having a concentration lower than a predetermined concentration. Alternatively, the stirrer is cleaned by empty-stirring operation not being put in a cleaning developer.