Photosensitive Layer Resin Composition for High-Temperature Reliability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Electrophotographic photosensitive members experience local dielectric breakdown under high-temperature and high-humidity conditions, leading to dot-shaped image defects due to reduced chargeability, and excessive use of polyester resin impairs sensitivity.

Innovation Solution

Incorporating a specific amount of polyester resin and polycarbonate resin in the photosensitive layer, with a content percentage of polyester resin between 0.3% to 7.0% by mass, to enhance withstand voltage and prevent image defects while maintaining sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyester resin is added to the photosensitive layer, then withstand voltage under high-temperature conditions is improved, but sensitivity deteriorates when excessive amount is used

Engineering Contradiction:
Improvewithstand voltage under high-temperature conditionsVSAvoidsensitivity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the content percentage of polyester resin in the photosensitive layer to be 0.3% to 7.0% by mass. This specific parameter range resolves the contradiction by optimizing the balance between withstand voltage improvement and sensitivity maintenance, preventing both dielectric breakdown and excessive sensitivity impairment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining polyester resin with polycarbonate resin in the photosensitive layer. This composite approach allows the polyester resin to provide enhanced withstand voltage under high-temperature conditions while the polycarbonate resin helps maintain sensitivity, thus resolving the technical contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #40Composite materials

2Reliability

If polyester resin content is increased to improve withstand voltage, then reliability under high-temperature conditions is improved, but image quality deteriorates due to reduced chargeability

Engineering Contradiction:
Improvewithstand voltage under high-temperature conditionsVSAvoiddot-shaped image defects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by setting the polyester resin content within the specific range of 0.3% to 7.0% by mass in the photosensitive layer. This optimized parameter prevents dielectric breakdown under high-temperature conditions while maintaining sufficient chargeability, thereby preventing dot-shaped image defects and ensuring high image quality.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If polyester resin is used to enhance withstand voltage, then reliability is improved, but sensitivity deteriorates

Engineering Contradiction:
Improvewithstand voltageVSAvoidsensitivity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the polyester resin content to 0.3% to 7.0% by mass and combining it with polycarbonate resin. This parameter optimization ensures that the photosensitive layer achieves high withstand voltage while maintaining excellent sensitivity, thus resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by formulating the photosensitive layer with both polyester resin and polycarbonate resin. The polyester resin provides enhanced withstand voltage, while the polycarbonate resin contributes to maintaining sensitivity, together resolving the technical contradiction between these two properties.

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

The combination of polyester and polycarbonate resins in the photosensitive layer improves withstand voltage under high-temperature conditions, preventing dot-shaped image defects and ensuring excellent sensitivity.

Implementation Method 1

the photosensitive layer contains a charge generating material, a binder resin, a hole transport material, and an electron transport material... the binder resin includes a polyester resin and a polycarbonate resin... improves withstand voltage under high-temperature conditions

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP3736634B1Electrophotographic photosensitive member, process cartridge, and image forming apparatus
Publication Date: 2024.09.18 KYOCERA DOCUMENT SOLUTIONS INC
  • EP3736634B1 patent drawingFigure 1~3
  • EP3736634B1 patent drawingFigure 4
  • EP3736634B1 patent drawing

AI summary

An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3) of a single layer. The photosensitive layer (3) contains a charge generating material, a binder resin, a hole transport material, and an electron transport material. The binder resin includes a polyester resin and a polycarbonate resin. The polyester resin includes a first repeating unit represented by general formula (1) shown below and a second repeating unit represented by general formula (2) shown below. The polycarbonate resin includes a third repeating unit represented by general formula (3) shown below and a fourth repeating unit represented by general formula (24) shown below. A content percentage of the polyester resin in the photosensitive layer is at least 0.3% by mass and no greater than 7.0% by mass.