Toner Concentration Control via Viscosity Feedback

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Solution Overview

Problem

Existing toner concentration adjustment systems for wet type developers face challenges in accurately adjusting toner concentration due to variations in viscosity caused by temperature and differences in toner particle size and form, especially when different lots of developers are mixed, leading to deviations from target values and image quality issues.

Innovation Solution

A toner concentration adjusting system that measures viscosity as a substitute characteristic to control the supply of concentrated developer and dispersion medium, using a cumulative supply amount and correction tables to adjust toner concentration, ensuring it aligns with a standard toner concentration target value, even when different lots of developers are used.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If viscosity measurement is used to detect toner concentration, then measurement is possible for high concentration developers, but measurement precision deteriorates due to temperature and particle size variations

Engineering Contradiction:

Improvetoner concentration measurementVSAvoidtoner concentration measurement precision

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The system changes the measurement parameter from direct optical measurement to viscosity measurement, which is feasible for high concentration developers. The control target value is dynamically adjusted based on temperature and particle size parameters to maintain measurement precision despite these variations affecting viscosity readings.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback mechanisms where the measured viscosity is compared against a dynamically adjusted control target value. The control target value correction section uses feedback from temperature sensors and particle size data to adjust the expected viscosity range, enabling precise control despite environmental variations.

Inventive Principle:

Principle #23Feedback

2Productivity

If different lots of developers are mixed to maintain supply, then productivity is improved, but toner concentration uniformity deteriorates due to lot-to-lot variations

Engineering Contradiction:

Improvedeveloper supply continuityVSAvoidtoner concentration uniformity

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The system adjusts the control target value parameter based on the specific lot being supplied. When a new lot is introduced, the system identifies it and applies lot-specific control target values that account for variations in toner particle size and viscosity characteristics, maintaining concentration uniformity across different lots.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system performs preliminary identification and characterization of each developer lot before mixing. By detecting lot variations in advance and pre-calculating appropriate control target values, the system prepares for potential composition changes before they affect the final product, ensuring continuous uniformity.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If optical sensor is used to measure toner concentration, then measurement is straightforward for low concentration developers, but measurement becomes impossible for high concentration developers due to light absorption

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidmeasurement applicability across concentration ranges

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system replaces the optical measurement mechanism with a viscosity-based measurement mechanism. Instead of using light transmission through the developer, the system measures viscosity using rotational torque, which remains effective across the full range of developer concentrations including high concentration formulations where optical methods fail.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system enables precise adjustment of toner concentration, reducing image quality variations and improving productivity by accounting for viscosity fluctuations and lot differences, thereby maintaining consistent image density across different developer lots.

Implementation Method 1

measuring viscosity of the wet type developer as a substitute characteristic of the toner concentration

Methodology Applied

Scientific EffectViscosity measurement:

Data Source

PatentUS8285165B2Toner concentration adjusting system and image forming apparatus using the same

Publication Date: 2012.10.09 KONICA MINOLTA INC

AI summary

The present invention provides a toner concentration adjusting system and an image forming apparatus which can accurately adjust toner concentration by controlling the supply of a concentrated developer even if a production lot of the concentrated developer is different. In the method, for controlling the toner concentration, in which the supply of the concentrated developer and the like to a wet type developer for which a first control target value is set is controlled while detecting a substitute characteristic of toner concentration, the first control target value is corrected depending on a second control target value based on a substitute characteristic of the toner concentration of the lot of the concentrated developer to be supplied, and depending on a cumulative supply amount of the lot of the concentrated developer.