Electrophotographic Photoreceptor Stabilizing Print Density
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Solution Overview
Problem
Conventional single layer-type positively-chargeable organic electrophotographic photoreceptors face challenges in achieving stable print density, especially in low-temperature environments, due to fluctuations in environmental conditions, which affect print density and durability.
Innovation Solution
Incorporating a prescribed phthalocyanine compound as a charge generating material and a naphthalene tetracarboxylic acid diimide compound as an electron transporting material in the photosensitive layer, either in a laminate-type or single layer-type structure, to stabilize print density by suppressing potential fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional single layer-type positively-chargeable organic photoreceptors are used, then the structure is simple and manufacturing is easier, but print density becomes unstable in low-temperature environments due to potential fluctuations
Solution Approach 1:
The photoreceptor is divided into functionally separated layers: a charge generation layer containing phthalocyanine compounds for generating charges, and a charge transport layer containing naphthalene tetracarboxylic acid diimide compounds for transporting charges. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between structural simplicity and print density stability by introducing functional specialization that compensates for environmental variations.
Solution Approach 2:
The invention uses composite material systems where specific phthalocyanine compounds (charge generating materials) are combined with specific naphthalene tetracarboxylic acid diimide compounds (electron transporting materials) in a laminated structure. This composite approach creates synergistic effects that maintain stable charge generation and transport across temperature variations, thereby stabilizing print density while maintaining reasonable manufacturing complexity.
2Device complexity
If the photoreceptor structure is simplified to a single layer-type, then manufacturing complexity is reduced, but durability and resistance to environmental variations deteriorate
Solution Approach 1:
The photoreceptor employs a laminated structure with distinct charge generation layer and charge transport layer, each containing specifically selected compounds. This functional segmentation enhances durability and environmental resistance by isolating degradation-prone components in separate layers that can be independently optimized and protected, while the overall structure remains relatively simple to manufacture.
3Adaptability or versatility
If conventional charge generating and transporting materials are used, then material selection is flexible and manufacturing is easier, but potential fluctuations occur in low-temperature environments affecting print density
Solution Approach 1:
The invention specifies particular compounds within the phthalocyanine and naphthalene tetracarboxylic acid diimide families, selecting materials with specific molecular structures and properties optimized for low-temperature performance. This parameter-based material selection (molecular structure, functional groups) ensures stable charge generation and transport potentials in low-temperature environments while maintaining reasonable flexibility within the specified compound classes.
Solution Approach 2:
The combination of specifically selected phthalocyanine charge generating materials with specifically selected naphthalene tetracarboxylic acid diimide electron transporting materials creates a composite system where the interaction between layers compensates for environmental variations. This composite material approach stabilizes potentials across temperature ranges while allowing flexibility in selecting specific compounds within the defined chemical families.
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 use of these specific materials in the photoreceptor's photosensitive layer ensures stable print density even in low-temperature environments, enhancing durability and resistance to environmental variations.
Implementation Method 1
a photosensitive layer having a photoconductive function is disposed on a conductive substrate
Implementation Method 2
a charge transport layer having both functions of retaining a surface charge in dark places and transporting the charge generated by the charge generation layer upon receiving light
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate; and a photosensitive layer arranged on the conductive substrate and containing, as a charge generating material, any one material selected from the group consisting of titanyl phthalocyanines, metal-free phthalocyanines, chlorogallium phthalocyanines and hydroxygallium phthalocyanines; and, as an electron transporting material, a naphthalene tetracarboxylic acid diimide compound represented by Formula (1) below, where R1 and R2 each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkylene group, an alkoxy group, an alkyl ester group, a phenyl group optionally having a substituent, a naphthyl group optionally having a substituent, or a halogen element; and R1 and R2 are optionally the same or different:The photoreceptor realizes a stable print density even in a low-temperature environment by suppressing a reduction in print density that is caused by potential fluctuation of the photoreceptor in the low-temperature environment.