Photoreceptor Charge Transport Layer for Low-Torque Blade Cleaning
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Solution Overview
Problem
Image forming apparatuses with lamination-type electrophotographic photoreceptors containing polyarylate resin in the charge transport layer face issues of increased rotational torque and reduced abrasion resistance, leading to a shorter lifespan due to excessive pressure from cleaning blades.
Innovation Solution
Incorporating a binder resin composed of polyarylate resin with a dicarboxylic acid unit and a diol unit, along with a polycarbonate resin, into the charge transport layer, and maintaining a contact line pressure of 2.4 gf/mm to 4.5 gf/mm, stabilizes the contact pressure and suppresses rotational torque while enhancing abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning blade is brought into contact with the photoreceptor at a contact line pressure of 2.4 gf/mm or more to effectively remove toner, then cleaning performance is improved, but rotational torque increases excessively and abrasion resistance decreases
Solution Approach 1:
The patent optimizes the contact line pressure parameter to a specific range (2.4-4.5 gf/mm) that balances cleaning effectiveness with torque control. This parameter change resolves the contradiction by identifying the optimal pressure threshold where sufficient toner removal occurs without causing excessive rotational torque that would reduce photoreceptor lifespan.
Solution Approach 2:
The photoreceptor surface layer uses a composite material composition containing fluorine-based resin particles (2-20 wt%) combined with specific polyarylate resin. This composite structure provides both the necessary surface properties for effective toner release at moderate pressure and enhanced durability to resist abrasion and control torque during operation.
2Reliability
If the contact line pressure is increased to ensure thorough toner removal, then cleaning effectiveness is improved, but abrasion resistance of the photoreceptor surface decreases
Solution Approach 1:
The patent establishes an optimal contact line pressure range (2.4-4.5 gf/mm) that achieves thorough toner removal without exceeding the threshold that would cause surface abrasion. This parameter optimization ensures cleaning effectiveness is maximized while preserving photoreceptor surface integrity and abrasion resistance over time.
Solution Approach 2:
The surface layer employs a composite material system with fluorine-based resin particles (2-20 wt%) and specific polyarylate resin that provides enhanced abrasion resistance. This composite structure allows the photoreceptor to withstand the mechanical stress of cleaning operations while maintaining surface integrity and preventing wear.
3Reliability
If fluorine-based resin particles are added to the surface layer to improve toner release, then cleaning performance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise quantitative parameters for fluorine-based resin content (2-20 wt%) and contact line pressure (2.4-4.5 gf/mm) to achieve optimal toner release performance. By defining these clear parameter ranges, the invention simplifies the manufacturing process through quantitative control rather than requiring complex qualitative adjustments, making production more straightforward and reproducible.
Data Source
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AI summary
An image forming apparatus includes an electrophotographic photoreceptor in which a conductive substrate, a charge generation layer, and a charge transport layer are laminated in this order, a charging device that charges a surface of the electrophotographic photoreceptor, an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor, a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image, a transfer device that transfers the toner image to a surface of a recording medium, and a cleaning device that has a cleaning blade for cleaning the surface of the electrophotographic photoreceptor with a contact line pressure of 2.4 gf/mm or more and 4.5 gf/mm or less, in which the charge transport layer contains a binder resin containing at least a polyarylate resin having a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B) and a polycarbonate resin, and a charge transport material. In Formula (A), n1 is 1, 2, or 3, n1 pieces of m1' s are each independently 0, 1, 2, 3, or 4, m1 pieces of Ra1' s are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms. In Formula (B), Rb1 and Rb2 are each independently a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, Rb3, Rb4, Rb5, Rb6, Rb7, Rb8, Rb9, and Rb10 are each independently a hydrogen atom, an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, an aralkyl group having 7 or more and 20 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, and Rb1 and Rb2 may be bonded to each other to form a cyclic alkyl group.