Charging Device Control Electrode Layout for Uniform Charging

Solution Overview

Problem

Existing charging devices experience charging unevenness due to vibration of the control electrode when connection portions are uniformly disposed along the axial direction of the charged body.

Innovation Solution

The control electrode is designed with a plurality of linear conductors intersecting the rotation direction of the charged body, with a higher density of connection portions in the central portion compared to the end portions, to mitigate charging unevenness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If connection portions are uniformly disposed along the axial direction of the charged body, then the control electrode structure is simple and easy to manufacture, but charging unevenness occurs due to vibration of the control electrode

Engineering Contradiction:

Improvecharging uniformityVSAvoidcontrol electrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The connection portions are arranged with different densities in different regions: a higher density in the central region and a lower density in the end regions. This local variation in connection portion density provides differential vibration suppression where needed most (center) while maintaining structural simplicity, thereby reducing charging unevenness without uniformly complicating the entire electrode structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The control electrode structure transitions from a symmetric uniform arrangement to an asymmetric arrangement where the connection portion density varies by region. The central region has a different connection portion density compared to the end regions, creating an asymmetric structure that specifically addresses vibration-induced charging unevenness in the critical central charging area.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If connection portions are densely disposed in the central portion, then vibration of the control electrode is suppressed and charging uniformity is improved, but the device complexity increases

Engineering Contradiction:

Improvecharging uniformityVSAvoidconnection portions arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The connection portions are arranged with different densities in different regions: a higher density in the central region and a lower density in the end regions. This local variation in connection portion density provides differential vibration suppression where needed most (center) while maintaining structural simplicity, thereby reducing charging unevenness without uniformly complicating the entire control electrode structure.

Inventive Principle:

Principle #3Local quality

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 effectively suppresses charging unevenness, ensuring consistent and uniform charging across the surface of the charged body, thereby improving image quality in image forming apparatuses.

Implementation Method 1

a discharge electrode; and a control electrode that is disposed between the discharge electrode and a charged body that is charged by the discharge electrode

Methodology Applied

Scientific EffectCorona discharge: Corona Discharge

Data Source

PatentUS20250306498A1Charging device, image forming unit, and image forming apparatus

Publication Date: 2025.10.02 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A charging device includes a discharge electrode; and a control electrode that is disposed between the discharge electrode and a charged body that is charged by the discharge electrode, in which the control electrode includes plural linear conductors disposed to intersect a rotation direction of the charged body at any angle, and plural connection portions that are members of connecting the linear conductors along the rotation direction of the charged body, and are disposed more in a region of a central portion than in a region of both end portions in a direction intersecting the rotation direction of the charged body.