Image Forming Apparatus Controller Stabilizing Development Density

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Solution Overview

Problem

Image forming apparatuses face challenges in maintaining stable development density due to time lags in reflecting control target value corrections, particularly with toner concentration and laser intensity, leading to excessive or inadequate development density, especially under changing temperature, humidity, and usage conditions.

Innovation Solution

An image forming apparatus with a controller that performs target value correction processing by adjusting control target values of parameters with different response speeds, prioritizing faster response parameters like developing bias to stabilize development density, and gradually correcting slower response parameters like toner concentration, while monitoring environmental changes and usage patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the control target value of toner concentration is greatly corrected to stabilize development density after long retention time, then the development density becomes appropriate, but it takes a certain period of time for the toner concentration to reach the corrected control target value, during which the developing ability is too low to achieve sufficient development density

Engineering Contradiction:

Improvedevelopment densityVSAvoidtime lag in correction reflection

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The controller performs preliminary correction of the control target value of toner concentration before the actual development process. By anticipating the time lag and pre-adjusting the control parameter, the system prepares the developing ability in advance to ensure sufficient development density is achieved from the start of operation after retention time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller monitors the development density and adjusts the control target value of toner concentration based on feedback from the development process. This closed-loop control allows the system to compensate for time lags by continuously observing the actual development outcome and making real-time corrections to the control parameter.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If the control target value of toner concentration is corrected to decrease developing ability after long retention time, then the development density becomes appropriate, but the toner charge amount increases to an average value and the developing ability becomes too low to achieve sufficient development density

Engineering Contradiction:

Improvedevelopment densityVSAvoiddeveloping ability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The controller dynamically adjusts the control target value of toner concentration based on the retention time and current development conditions. By changing this parameter adaptively rather than using a fixed correction value, the system maintains appropriate developing ability while achieving stable development density, preventing the toner charge amount from becoming excessively high.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the control target value of toner concentration is greatly corrected in accordance with temperature and humidity change, then the development density becomes appropriate, but the toner concentration greatly deviates from the appropriate value until it reaches the corrected control target value

Engineering Contradiction:

Improvedevelopment densityVSAvoidtime lag in concentration adjustment

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

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 approach promptly stabilizes development density by addressing time lags in correction reflection, ensuring consistent output despite environmental and operational changes, and preventing poor development density during parameter correction periods.

Implementation Method 1

electrical adhesion of toner particles attracting to the carrier in the two-component developer

Methodology Applied

Scientific EffectElectrical adhesion: Electrostatics

Implementation Method 2

the two-component developer is stirred in the developing device, which promotes triboelectric charging of toner

Methodology Applied

Scientific EffectTriboelectric charging: Triboelectric Effect

Data Source

PatentUS9146498B2Image forming apparatus

Publication Date: 2015.09.29 RICOH CO LTD

AI summary

An image forming apparatus includes a controller and an imaging unit having a developing device to develop a latent image on a surface of a latent image carrier with toner. When control target value of control parameters that influence a developing ability of the imaging unit becomes inappropriate, the controller performs target value correction processing of correcting the control target value to bring the control target value close to an appropriate value for stabilizing a development density of the imaging unit. In the target value correction processing, the controller corrects a control target value of a second control parameter having a response speed, obtained when the developing ability is changed by the correction, faster than a first control parameter, correct the control target value of the first control parameter, and then turn the control target value of the second control parameter back to the original value.