Segmented Toner Particles for Image Deletion Suppression
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Solution Overview
Problem
In electrophotographic methods, image deletion occurs due to ionic substances adhering to the photoreceptor surface, causing disturbance in latent image charges, especially in high humidity environments, leading to image blurring. Existing solutions, such as using toner with metal stearate particles, have limitations in effectively removing these substances.
Innovation Solution
The toner composition includes first particles with a binder resin core and a shell layer, and second particles with a metal stearate core and shell layer, where the metal stearate content is 50% or more, and the second particle ratio is between 5% and 25%, allowing for effective removal of ionic substances during the image fixing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal stearate particles are added to suppress image deletion, then image quality is improved, but fogging may occur due to excessive metal stearate adhesion to photoreceptor
Solution Approach 1:
The toner is segmented into two distinct particle types: first particles containing binder resin and second particles containing metal stearate. This segmentation allows controlled delivery of metal stearate to the photoreceptor surface, sufficient to suppress image deletion but not excessive to cause fogging, thereby resolving the contradiction between image quality improvement and fogging prevention.
Solution Approach 2:
The invention changes the parameter of metal stearate content control by forming it as core material in second particles with specific composition ratios (5-50 mass%). This parameter control ensures that metal stearate is supplied in optimal amounts to suppress image deletion without causing fogging, resolving the contradiction between these two opposing effects.
2Reliability
If high metal stearate content is used to effectively remove ionic substances, then image deletion is suppressed, but toner stability and handling become difficult
Solution Approach 1:
By segmenting the toner into first particles (binder resin) and second particles (metal stearate), the invention achieves effective ionic substance removal through controlled metal stearate release while maintaining toner stability. The segmented structure prevents excessive metal stearate exposure that would compromise toner stability, thus resolving the contradiction between image deletion suppression and toner stability.
Solution Approach 2:
The invention creates a composite toner system combining binder resin and metal stearate in specific proportions (15-65 mass% second particles). This composite structure achieves the dual benefit of effective image deletion suppression through metal stearate while maintaining overall toner stability through the binder resin matrix, resolving the contradiction between these two requirements.
3Productivity
If metal stearate particles are used to adhere to ionic substances, then cleaning efficiency is improved, but image sharpness may be reduced due to excessive adhesion
Solution Approach 1:
The invention optimizes the parameter of metal stearate content by controlling it within specific ranges (5-50 mass% in second particles, 15-65 mass% of total toner). This parameter optimization ensures sufficient metal stearate for effective cleaning of ionic substances while preventing excessive adhesion that would compromise image sharpness, thereby resolving the contradiction between cleaning efficiency and image sharpness.
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 suppresses image deletion and fogging by ensuring the metal stearate is supplied to the photoreceptor surface, where it can be rapidly removed with the ionic substances, maintaining image clarity and sharpness.
Implementation Method 1
the affinity between the ester structure in the metal stearate particles and the ionic substance is high
Implementation Method 2
owing to the lubricating ability of the metal stearate, the facility of removal of the metal stearate particles from the surface of the photoreceptor is high
Data Source
AI summary
Toner includes, as toner particles, first particles and second particles. The first particles each include a first core and a first shell layer covering a surface of the first core. The first core contains a first binder resin and is free from metal stearates. The second particles each include a second core and a second shell layer covering a surface of the second core. The second core contains a metal stearate. The first shell layer and the second shell layer are formed of resins of the same type, respectively. The content of the metal stearate in the second core is 50% by mass or more with respect to the mass of the second core as a whole. The number ratio of the second particles is 5% or more but 25% or less of the total number of the first particles and the second particles.