Positively-Chargeable Photoreceptor Surface Contact Angle Control
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Solution Overview
Problem
In electrophotographic printers, especially under high-temperature and high-humidity environments, positively-chargeable organic photoreceptors face issues with fine black or color spots due to toner and paper dust deposition, leading to image defects and toner filming, which existing solutions fail to adequately address.
Innovation Solution
The development of a positively-chargeable electrophotographic photoreceptor with a contact angle between the outermost layer and water controlled within a range of 81° to 87°, utilizing specific charge generation materials like titanyl phthalocyanine and binder resins, to inhibit moisture adsorption and deposition of toner and paper dust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positively-chargeable organic photoreceptor is used, then the benefits of positive charging systems are achieved including suppressed ozone generation and improved dot reproducibility, but fine black or color spots occur due to toner and paper dust deposition under high-temperature and high-humidity environments
Solution Approach 1:
The patent applies parameter changes by controlling the contact angle of the photoreceptor surface to be within a specific range (81° to 87°). This parameter control modifies the surface properties to reduce moisture adsorption, thereby preventing toner and paper dust deposition that causes fine black or color spots under high-temperature and high-humidity conditions.
Solution Approach 2:
The patent uses composite materials by combining specific binder resins (polycarbonate-based resin with bisphenol A structure and polyester resin) with charge generation materials (including titanyl phthalocyanine). This composite approach creates a photoreceptor layer with optimized surface properties that control moisture interaction and prevent dust deposition while maintaining electrophotographic performance.
2Manufacturing precision
If the contact angle is controlled within 81° to 87°, then moisture adsorption is suppressed and fine black or color spots are prevented, but the formulation of binder resins and charge generation materials becomes more complex
Solution Approach 1:
The patent applies local quality by selecting specific binder resins with particular chemical structures (polycarbonate-based resin containing bisphenol A and polyester resin) to achieve the desired contact angle range. This localized material selection focuses the complexity on the surface layer composition rather than the entire photoreceptor structure, allowing precise control of surface properties.
3Power
If titanyl phthalocyanine is used as charge generation material, then charge generation efficiency is improved, but the susceptibility to moisture adsorption and dust deposition increases without proper surface treatment
Solution Approach 1:
The patent uses binder resins (polycarbonate-based resin and polyester resin) as intermediary materials between the charge generation material (titanyl phthalocyanine) and the environment. These binder resins form a protective matrix that reduces direct exposure of the charge generation material to moisture while maintaining its charge generation functionality.
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 solution effectively suppresses the generation of fine black or color spots and toner filming, ensuring high image quality and durability in various environmental conditions.
Implementation Method 1
a contact angle between the surface of an outermost layer of the photoreceptor and water is in a range of 81° to 87°
Implementation Method 2
inhibit moisture adsorption and deposition of toner and paper dust
Implementation Method 3
an exposure device which generates an electrical image (electrostatic latent image) corresponding to an image on the surface of the photoreceptor
Implementation Method 4
organic photoreceptors (or OPC: organic photoconductors) in which an organic pigment is dispersed in a resin
Implementation Method 5
a transfer device which transfers the toner image onto a transfer paper
Data Source
AI summary
An electrophotographic photoreceptor which, even when mounted on a high-image-quality monochrome high-speed printer or tandem color printer including a cleaner-less process of a non-magnetic single-component contact development system using a polymerized toner, inhibits the generation of fine black spots or color spots and suppresses the occurrence of toner filming during the initial printing under a high-temperature and high-humidity environment and thereby stably attains a high image quality in a variety of environments. The electrophotographic photoreceptor is a positively-chargeable electrophotographic having a contact angle between the surface of an outermost layer and water that is in a range of 81° to 87° and having a binder resin of an outermost layer containing resins having repeating units represented by Formula (1) and Formula (2) below: