Developing Roller Impedance Tuning for Stable Toner Charging
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Solution Overview
Problem
Existing toners with a high content of crystalline resin for low-temperature fixability suffer from charge stability issues, leading to image fogging and reduced image density due to charge leakage and excessive adhesion to the developing roller.
Innovation Solution
A developing apparatus with a toner having resistivity ≤ 2.00×10^14 Ω·m and specific impedance and phase characteristics of the developing roller, along with a conductive outer surface and resin layer, to stabilize charge and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the toner contains a large amount of crystalline resin to achieve low-temperature fixability, then the fixation temperature is lowered, but the resistance of the toner is decreased causing insufficient charge quantity and image fogging
Solution Approach 1:
The patent changes the electrical parameters of the developing roller by controlling its impedance (Z) and phase angle (θ) at specific frequencies. The developing roller is designed to have an impedance Z of 1.00×10^4 Ω or more at 1.0×10^2 Hz and a phase angle θ of -40° to -10° at the same frequency, which stabilizes the charge on the toner particles and prevents image fogging while maintaining low-temperature fixability
Solution Approach 2:
The developing roller uses a composite structure combining a conductive substrate with a resin layer having specific electrical properties. This composite design allows the roller to provide both conductivity for charge control and resistance for charge stabilization, resolving the contradiction between low-temperature fixability and charge stability
2Reliability
If the resistance value of the developing roller is increased to maintain toner charge, then charge stability is improved, but significant charge-up occurs on the developing roller surface during continuous printing causing excessive adhesion and reduced image density
Solution Approach 1:
The patent precisely controls the impedance and phase angle parameters of the developing roller to achieve optimal charge stability without excessive charge-up. By setting the impedance Z ≥ 1.00×10^4 Ω at 1.0×10^2 Hz and phase angle θ between -40° and -10° at the same frequency, the system maintains charge stability while preventing harmful charge accumulation on the roller surface during continuous operation
Solution Approach 2:
The developing roller design incorporates feedback mechanisms through its impedance and phase angle characteristics that automatically regulate charge transfer. The specific parameter ranges ensure that the roller maintains appropriate charge levels without causing excessive adhesion or image density reduction, even during continuous high-density printing
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 solution effectively suppresses image fogging and maintains image density by stabilizing charge on the toner, ensuring high charge stability and low-temperature fixability.
Implementation Method 1
the developing roller has an impedance Z of at least 1.00×10^4 Ω at a frequency of 1.0×10^2 Hz, obtained by AC impedance measurement
Implementation Method 2
the toner has a resistivity of not more than 2.00×10^14 Ω·m at a frequency of 0.01 Hz, obtained by AC impedance measurement
Implementation Method 3
a substrate having a conductive outer surface
Data Source
AI summary
A developing apparatus including a developing roller and a toner is provided, in which the toner includes a toner particle containing a crystalline material, the toner has a resistivity of not more than 2.00×1014 Ω·m at a frequency of 0.01 Hz, obtained by AC impedance measurement, the developing roller includes a substrate having a conductive outer surface and a resin layer on the outer surface of the substrate, the developing roller has an impedance Z of at least 1.00×104 Ω at a frequency of 1.0×102 Hz, obtained by AC impedance measurement, the developing roller has a phase θ1 of −40° to −10° at a frequency of 1.0×102 Hz, obtained by AC impedance measurement, and the developing roller has a phase not more than θ2 of −60° at a frequency of 1.0×104 Hz, obtained by AC impedance measurement is.