Photoconductive Drum Charge Removal via Localized Light Width

Solution Overview

Problem

Image defects occur in image forming apparatuses due to light used for removing photoconductive drum charge leaking to the upstream side of the toner image transfer position, affecting the quality of the transferred images.

Innovation Solution

An image forming apparatus is designed with a charge removing member that emits light towards the photoconductive drum after toner image transfer, with an effective light receiving width less than the transfer member width, ensuring that residual charges are removed without affecting the toner image, and the charge removing position is strategically positioned between the transfer and cleaning positions to minimize interference with the image forming area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light source is used to remove residual charges on the photoconductive drum, then charge removal effectiveness is improved, but image defects occur due to light leakage to the upstream side of the transfer position

Engineering Contradiction:

Improvecharge removal effectivenessVSAvoidimage defects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by making the light receiving width of the photoconductive drum smaller than the width of the transfer member in the width direction. This creates a localized effective illumination area that confines the charge removal effect to the downstream side of the transfer position, preventing light from affecting the upstream side where toner images are formed, thus resolving the contradiction between charge removal effectiveness and image quality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a dimensional constraint by comparing and controlling the width dimensions of the photoconductive drum's light receiving area relative to the transfer member width. By operating in the width dimension and establishing a specific size relationship (light receiving width < transfer member width), the patent confines the light effect spatially to prevent upstream contamination while maintaining downstream charge removal

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the light receiving width of the photoconductive drum is reduced, then light leakage to the upstream side is prevented, but charge removal coverage may be insufficient

Engineering Contradiction:

Improvelight leakage preventionVSAvoidcharge removal coverage

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by making the light receiving width of the photoconductive drum smaller than the width of the transfer member in the width direction. This creates a localized effective illumination area that confines the charge removal effect to the downstream side of the transfer position, preventing light from affecting the upstream side where toner images are formed, thus resolving the contradiction between charge removal effectiveness and image quality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a dimensional constraint by comparing and controlling the width dimensions of the photoconductive drum's light receiving area relative to the transfer member width. By operating in the width dimension and establishing a specific size relationship (light receiving width < transfer member width), the patent confines the light effect spatially to prevent upstream contamination while maintaining downstream charge removal

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 image defects by ensuring that the charge removing light does not interfere with the toner image, maintaining image quality and preventing toner jumping, while achieving a sufficient charge removing effect.

Implementation Method 1

a light source that emits light toward the surface of the image carrier after transfer of the toner image to remove residual charges on the photoconductive layer

Methodology Applied

Scientific EffectPhotoconductive effect: Photoconductivity

Data Source

PatentUS10761471B2Image forming apparatus that removes residual charges on image carrier

Publication Date: 2020.09.01 TOSHIBA TEC KK

AI summary

An image forming apparatus includes an image carrier, a transfer member, and a light source. The image carrier has a photoconductive layer on a surface of the image carrier. The transfer member is configured to cause a toner image formed on the surface of the image carrier to be transferred to a transferee member at a transfer position of the image carrier. The light source is configured to emit light toward the surface of the image carrier after transfer of the toner image to remove residual charges on the photoconductive layer. An effective light receiving width of the image carrier in a width direction thereof is less than a width of the transfer member.