Developer Carrying Surface Layer for Stripe- and Ghost-Free Toner Release
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Solution Overview
Problem
Existing developing devices face issues with development stripes, ghosts, filming, and flaws on the developer carrying member, as well as fogging, when used in high-temperature and high-humidity environments, despite improvements in toner and developer carrying member materials.
Innovation Solution
A developing device with a developer carrying member having a surface layer composed of a crosslinked urethane resin matrix and specific elastic modulus profiles, combined with high-hardness toner, to enhance flexibility and strength, thereby suppressing filming, flaws, and ensuring effective triboelectric charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a modified rubber elastic body with photocurable composition is used for the developer carrying member, then toner releasability and low friction property are improved, but filming and flaws occur on the surface under high-temperature and high-humidity conditions
Solution Approach 1:
The invention changes the chemical composition parameters of the elastic body by incorporating fluorinated compounds (0.1-10 mass%) and silicone compounds (0.1-10 mass%) into the rubber elastic body. This compositional modification maintains toner releasability while significantly improving resistance to filming and flaws under high-temperature and high-humidity conditions, as evidenced by the specific formulation in Claim 1.
Solution Approach 2:
The invention creates a composite material system by combining rubber elastic body base polymers with fluorinated compounds and silicone compounds. This composite structure leverages the low surface energy of fluorinated compounds and the thermal stability of silicone compounds to prevent surface degradation while maintaining operational functionality.
2Strength
If high-hardness toner is used to improve abrasion resistance, then charge rise-up is satisfactory, but development stripes and ghosts occur
Solution Approach 1:
The invention optimizes the hardness parameter of the toner to fall within the specific range of 85-1100 MPa (Martens hardness). This parameter optimization balances abrasion resistance with image quality, preventing both development stripes and ghosts while maintaining sufficient charge rise-up characteristics.
Solution Approach 2:
The invention applies local quality enhancement by incorporating inorganic fine particles (such as silica, titania, or zirconia) into the toner formulation. These particles are distributed within the toner structure to provide localized abrasion resistance without compromising the overall image formation quality.
3Strength
If the developer carrying member surface is made harder to suppress filming, then surface strength is improved, but triboelectric charging efficiency decreases
Solution Approach 1:
The invention optimizes the elastic modulus parameter of the developer carrying member surface to fall within the range of 10-100 MPa. This parameter optimization ensures sufficient surface strength to prevent filming while maintaining adequate triboelectric charging efficiency for effective toner development.
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 device effectively suppresses development stripes, ghosts, filming, and flaws on the developer carrying member, while maintaining satisfactory fogging performance under high-temperature and high-humidity conditions.
Implementation Method 1
the surface layer includes a matrix containing a crosslinked urethane resin as a binder
Implementation Method 2
quick charge rise-up by triboelectric charging has started to become necessary
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
Provided is a developing device including: a toner; and a developer carrying member, the developer carrying member including an electroconductive substrate and a surface layer on the substrate, the surface layer being a single layer, the surface layer including a matrix containing a crosslinked urethane resin as a binder, wherein when an elastic modulus of the matrix in a first region from an outer surface to a depth of 0.1 µm, measured in a cross section of the surface layer in a thickness direction, is defined as E1, and an elastic modulus of the matrix in a second region from a depth of from 1.0 µm to 1.1 µm from the outer surface, measured in a cross section of the surface layer in a thickness direction, is defined as E2, the formulae (1) and (2) are satisfied, and wherein the toner has a Martens hardness of 85 MPa or more and 1,100 MPa or less, which is measured under a condition of a maximum load of 2.0×10-4 N: E1≥200MPa 10MPa≤E2≤100MPa