Charging Roller Cleaning Member Structure to Prevent Print Defects

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Solution Overview

Problem

In contact charging type image forming apparatuses, foreign matter from the cleaning member adheres to the charging member, leading to printing defects due to the adhesion of external additives like toner, which affects the charging condition of the photosensitive drum.

Innovation Solution

A charging device with a rotatable cleaning member featuring a core bar and a helically wound foam member with a gap, where a first adhesive agent forms a sandwich structure to prevent foreign matter exposure and adherence to the charging member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cleaning member is used to remove foreign matter from the charging member, then the charging condition is improved, but foreign matter from the cleaning member adheres to the charging member causing printing defects

Engineering Contradiction:
Improvecharging condition stabilityVSAvoidforeign matter adhesion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The adhesive agent is extracted and separated from the foam member as a distinct layer. This adhesive layer is specifically designed to contact the charging member, while the foam member provides the cleaning function. By separating these functions into distinct layers, the adhesive agent can be optimized to prevent foreign matter adhesion without compromising the cleaning capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive agent acts as an intermediary layer between the foam member and the charging member. This intermediate layer prevents direct contact between foreign matter and the charging member surface, while still allowing the cleaning action to be transmitted from the foam member. The adhesive agent mediates the interaction, preventing harmful adhesion while maintaining cleaning effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the cleaning member contacts the charging member to remove toner, then cleaning effectiveness is improved, but foreign matter is flung up and adheres to the charging member surface

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidforeign matter flinging
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The adhesive agent serves as a protective intermediary that prevents foreign matter from being flung onto the charging member surface during the cleaning process. While the foam member effectively removes toner, the adhesive layer blocks the path of flung foreign matter, preventing it from adhering to the charging member and causing printing defects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive agent is applied in advance to the foam member before it contacts the charging member. This preliminary application creates a protective barrier that prevents foreign matter adhesion before the cleaning action occurs. The adhesive agent is positioned to intercept foreign matter before it can reach the charging member surface.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If a foam member is used to clean the charging member, then foreign matter removal is improved, but adhesive agent exposure and foreign matter adhesion occur

Engineering Contradiction:
Improveforeign matter removalVSAvoidadhesive agent exposure
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The cleaning member is segmented into distinct functional layers: the foam member for foreign matter removal and the adhesive agent layer for preventing adhesion. This segmentation allows each layer to perform its specific function optimally without interfering with the other. The adhesive layer is segmented to cover the entire contact surface, ensuring complete protection against foreign matter adhesion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cleaning member uses a composite structure combining the foam member and adhesive agent in a multi-layer configuration. This composite design integrates the cleaning capabilities of the foam material with the protective adhesive properties, creating a unified component that performs both foreign matter removal and adhesion prevention simultaneously.

Inventive Principle:
Principle #40Composite materials

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 design inhibits the adhesion of foreign matter to the charging member, maintaining high print quality by preventing contamination and ensuring stable charging conditions.

Implementation Method 1

a first adhesive agent that is provided between the foam member and the core bar, the first adhesive agent contacting a part of the foam member and another part of the foam member that are formed to adjoin each other in the lengthwise direction via the gap

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3992724B1Charging device, image forming unit, image forming apparatus, and method of manufacturing cleaning member
Publication Date: 2026.02.25 OKI ELECTRIC INDUSTRY CO LTD
  • EP3992724B1 patent drawingFigure 1
  • EP3992724B1 patent drawingFigure 2
  • EP3992724B1 patent drawingFigure 3

AI summary

A charging device (16) includes a charging member (32) that is rotatable and contacts and electrically charges a surface of a charging target member (14); and a cleaning member (34) that is rotatable and cleans a surface of the charging member (32), wherein the cleaning member (34) includes a core bar (34a) extending in a lengthwise direction, a foam member (34d) that is helically wound around the core bar (34a) while forming a gap (34dG) in the lengthwise direction and contacts the charging member (32), and a first adhesive agent (34c1) that is provided between the foam member (34d) and the core bar (34a), the first adhesive agent (34c1) contacting a part of the foam member (34d) and another part of the foam member (34d) that are formed to adjoin each other in the lengthwise direction via the gap (34dG).