Electrophotographic apparatus
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Solution Overview
Problem
Existing electrophotographic apparatuses experience a decrease in transfer efficiency and toner scattering after endurance due to uneven chargeability of toner in the developing roller's surface layer, leading to decreased image quality.
Innovation Solution
The electrophotographic apparatus incorporates a monolayer photosensitive layer containing a charge generating material, a hole transporting material, and a specific polyester resin with structural units that enhance electron accepting properties, along with a developing roller having an elastic layer and a coating layer with a silica particle and a second binder resin, to uniformize toner charge and prevent scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a developing roller with a coating layer containing silica particles is used to suppress filming, then filming is suppressed, but transfer efficiency decreases and toner scattering occurs after endurance
Solution Approach 1:
The patent changes the material parameters of the photosensitive layer by using a polyester resin with specific structural units (formula 1 and formula 2) that have high electron accepting properties. This parameter change in the photosensitive layer material enables uniform toner chargeability even when using a silica-containing coating layer on the developing roller, thereby maintaining transfer efficiency after endurance while still suppressing filming.
Solution Approach 2:
The patent uses a composite material approach by combining a polyester resin with specific structural units in the photosensitive layer that works synergistically with the silica particles in the developing roller coating layer. This composite system allows the silica particles to suppress filming while the specific polyester resin structure ensures uniform toner charging, resolving the contradiction between filming suppression and transfer efficiency maintenance.
2Object-generated harmful factors
If the developing roller surface layer is made flexible to suppress filming, then filming is suppressed, but toner chargeability becomes uneven leading to toner scattering
Solution Approach 1:
The patent changes the chemical composition parameters of the photosensitive layer by incorporating a polyester resin with specific structural units (formula 1 and formula 2) that possess high electron accepting properties. This parameter change enables the photosensitive layer to uniformly charge toner particles even when the developing roller surface is flexible, thereby preventing toner scattering while maintaining filming suppression.
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 configuration maintains high image quality from the initial stage to after endurance by suppressing toner scattering and transfer efficiency loss, ensuring consistent image quality over time.
Implementation Method 1
an exposing unit configured to irradiate the charged surface of the electrophotographic photosensitive member with light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member
Implementation Method 2
a developing roller including a shaft body, an elastic layer arranged on an outer periphery of the shaft body
Data Source
AI summary
Provided is an electrophotographic apparatus including: an electrophotographic photosensitive member; a charging unit; an exposing unit; and a developing unit, wherein the electrophotographic photosensitive member includes a monolayer type photosensitive layer containing a charge generating material, a hole transporting material, an electron transporting material, and a first binder resin, wherein the photosensitive layer contains, as the first binder resin, a polyester resin having specific structural units, wherein the developing unit is a developing roller including a shaft body, an elastic layer arranged on an outer periphery of the shaft body, and a coating layer arranged on an outer periphery of the elastic layer, and wherein the coating layer contains a second binder resin and a silica particle.