Dielectric Shielding Member for Charge Leakage Prevention

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Solution Overview

Problem

In miniaturized electrophotographic image forming apparatuses, the short interval between the charging device and the exposure device leads to electrification charge leakage, disrupting image formation and preventing further miniaturization.

Innovation Solution

A dielectric shielding member with a dielectric constant of 5.0 or less is placed between the charging device and the exposure position, maintaining a specific gap to prevent electrification charge leakage and ozone deterioration, while allowing for close proximity of the charging and exposure devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the image forming apparatus is miniaturized to reduce installation space, then the device size is reduced, but the interval between charging device and exposure device becomes short causing electrification charge leakage

Engineering Contradiction:

Improvedevice sizeVSAvoidelectrification charge leakage

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

A dielectric shielding member is introduced as an intermediary component between the charging device and the exposure device. This shielding member has a dielectric constant of 5.0 or less and is positioned with a specific gap to block the leakage of electrification charge from the charging device to the exposure device, thereby preventing image quality deterioration while enabling miniaturization.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent specifies precise parameter control for the dielectric shielding member, including its dielectric constant (≤5.0) and the gap distance from the image carrier surface (0.1mm to 5.0mm). By optimizing these parameters, the shielding member effectively prevents charge leakage without occupying excessive space, thus resolving the contradiction between miniaturization and charge leakage prevention.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the interval between charging device and exposure device is reduced for miniaturization, then space is saved, but ozone deterioration affects the image carrier

Engineering Contradiction:

Improvedevice sizeVSAvoidozone deterioration

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The dielectric shielding member serves as a protective intermediary that not only blocks electrification charge leakage but also mitigates ozone deterioration. By positioning this shielding member with appropriate gap distance, it creates a protective barrier that prevents direct exposure of the image carrier to ozone generated during the charging process, enabling closer spacing of components.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a dielectric shielding member is added to prevent charge leakage, then charge leakage is prevented, but device complexity increases

Engineering Contradiction:

Improveelectrification charge leakageVSAvoidstructure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent simplifies the overall device structure by carefully controlling the parameters of the dielectric shielding member. By specifying a dielectric constant of 5.0 or less and an optimal gap range (0.1mm to 5.0mm), the design achieves effective charge leakage prevention with minimal additional complexity. The shielding member can be implemented as a simple component integrated into the existing charging device housing.

Inventive Principle:

Principle #35Parameter changes

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 prevents electrification charge leakage and ozone-related defects, enabling the miniaturization of image forming apparatuses without compromising image quality, especially in full-color printers with multiple process units.

Implementation Method 1

a dielectric shielding member with a dielectric constant of 5.0 or less is placed between the charging device and the exposure position

Methodology Applied

Scientific EffectElectrostatic shielding: Faraday Cage

Implementation Method 2

maintaining a specific gap to prevent electrification charge leakage and ozone deterioration

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS9141021B2Image forming apparatus with reduced charge leakage

Publication Date: 2015.09.22 KK TOSHIBA

AI summary

An image forming apparatus includes an image carrier whose surface is moved in a specific direction, a charging device to charge the image carrier, an exposure device to form an electrostatic latent image by exposing a surface of the charged image carrier, a developing device to supply a developer to the image carrier on which the electrostatic latent image is formed, a transfer device to transfer a developer image formed on the surface of the image carrier onto an image forming medium, and a dielectric member that extends from the charging device to the vicinity of the image carrier and is disposed between the charging device and the image carrier surface part exposed by the exposure device, in which the charging device, the exposure device, the developing device and the transfer device are sequentially arranged around the image carrier along the movement direction of the surface of the image carrier.