Toner Band Density Control in Two-Component Developing

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Solution Overview

Problem

Image forming apparatuses using two-component developers face challenges in maintaining optimal toner density, leading to potential image defects due to developer degradation, especially when external additives embed in the carrier, causing uneven toner distribution and consumption.

Innovation Solution

The apparatus incorporates a developing device with a two-component developer, a density detection unit, and a determining unit that assesses the toner band density to decide on necessary adjustments, forming a toner band to refresh the developer and adjust image density by controlling the bias voltage and exposure, ensuring consistent toner distribution across multiple colors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a two-component developer is used for developing, then developing efficiency is improved, but toner density becomes unstable due to external additives embedding in the carrier

Engineering Contradiction:

Improvedeveloping efficiencyVSAvoidtoner density stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by detecting the density of the toner band and comparing it with a reference density. When the detected density falls outside the reference range, the system automatically performs density adjustment by controlling the developing device to form a new toner band, thereby maintaining stable toner density despite developer degradation over time.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the parameter of toner band density through controlled adjustment processes. By monitoring density parameters and adjusting the developing conditions (such as bias voltage or exposure) when deviations are detected, the system maintains optimal toner density and prevents image defects caused by developer degradation.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If developer is used continuously without adjustment, then productivity is maintained, but image quality deteriorates due to uneven toner distribution

Engineering Contradiction:

Improvecontinuous operation capabilityVSAvoidimage quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system continuously monitors toner band density and provides feedback to the control unit. This enables the system to detect degradation in toner distribution and trigger density adjustment operations, ensuring image quality is maintained throughout continuous operation without manual intervention.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis and self-adjustment by automatically detecting toner band density and initiating density adjustment when needed. This self-service capability allows the system to maintain image quality autonomously during continuous operation, eliminating the need for external monitoring or manual adjustment.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If density adjustment is performed frequently, then image density consistency is improved, but operation time is consumed

Engineering Contradiction:

Improveimage density consistencyVSAvoidoperation time for density adjustment

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs density adjustment only partially or selectively - specifically when the detected toner band density falls outside the reference range. This avoids unnecessary full adjustment operations, reducing time consumption while still maintaining adequate image density consistency through targeted adjustments.

Inventive Principle:

Principle #16Partial or excessive 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 solution effectively maintains desired image density by determining the need for density adjustments based on detected toner band changes, preventing defects and ensuring consistent output across 100 pages, thereby extending developer life and improving image quality.

Implementation Method 1

a density detection unit that detects a density of the toner band

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a developing device that performs a developing process by using two-component developer

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS10289047B2Image forming apparatus and non-transitory computer readable medium

Publication Date: 2019.05.14 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes a developing device that performs a developing process by using two-component developer; an image carrier that carries a toner image including a toner band developed by the developing device; a density detection unit that detects a density of the toner band; and a determining unit that determines whether or not to perform a density adjustment on the basis of the density of the toner band detected by the density detection unit.