Electrophotographic Photosensitive Drum Composite Surface Structure

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electrophotographic photosensitive members face challenges in achieving both a reduction in torque during cleaning and improved image transferability due to differing requirements for reducing the area of contact with the cleaning blade and toner, respectively, which are not effectively addressed by existing surface structures.

Innovation Solution

The photosensitive member features a composite structure with two distinct groups of surface patterns: one with smaller appearance periods and lower heights for reducing torque, and another with larger appearance periods and higher heights for enhancing image transferability, isotropically arranged to maintain cleaning efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a single surface structure is used to reduce the area of contact with the cleaning blade, then torque during cleaning is reduced, but image transferability deteriorates due to excessive contact area with toner

Engineering Contradiction:
Improvetorque during cleaningVSAvoidimage transferability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The surface structure is segmented into two distinct groups: a first structure group with smaller appearance periods and lower heights for reducing torque, and a second structure group with larger appearance periods and higher heights for improving image transferability. This segmentation allows each structure to serve its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the photosensitive member surface are assigned different local qualities through the two structure groups. The first structure group provides low torque characteristics in certain areas, while the second structure group provides improved image transferability in other areas, creating spatially differentiated functional properties.

Inventive Principle:
Principle #3Local quality

2Productivity

If the area of contact with the cleaning blade is reduced, then cleaning efficiency is improved, but residual toner escapes from the contact portion

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidcleaning completeness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The surface is divided into two structure groups with different appearance periods. The first structure group with smaller appearance periods reduces the contact area with the cleaning blade, improving cleaning efficiency. The second structure group with larger appearance periods ensures complete cleaning by preventing residual toner escape, thus resolving the contradiction between cleaning efficiency and completeness.

Inventive Principle:
Principle #1Segmentation

3Force

If surface unevenness is increased to reduce contact area, then frictional force and torque are reduced, but the complexity of surface processing increases

Engineering Contradiction:
Improvefrictional forceVSAvoidsurface processing complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The complex surface unevenness is segmented into two distinct structural patterns with different appearance periods. This segmentation simplifies the processing by allowing each pattern to be formed through separate, well-defined procedures rather than attempting to create a single complex uneven surface, thus reducing processing complexity while maintaining the desired friction reduction effect.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3901702B1Electrophotographic photosensitive member, process cartridge, and electrophotographic image forming apparatus
Publication Date: 2025.06.25 CANON KK
  • EP3901702B1 patent drawingFigure 1A~1B
  • EP3901702B1 patent drawingFigure 2A~2D
  • EP3901702B1 patent drawingFigure 3A~3B

AI summary

Provided is an electrophotographic photosensitive drum that achieves both of a reduction in torque of the electrophotographic photosensitive drum at the time of its cleaning and an improvement in image transferability. The electrophotographic photosensitive drum includes: a support; and a photosensitive layer arranged on the support, the electrophotographic photosensitive drum having arranged on an outer surface thereof at least two structure groups having different appearance periods, wherein when, out of the two structure groups, a group including structures having a smaller appearance period is defined as a first structure group, and a group including structures having a larger appearance period is defined as a second structure group, a height of the first structure group is lower than a height of the second structure group.