Toner Shape Factor and Hydrophobic Oxide for Cleaning Efficiency
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the use of toner with a nearly true spherical shape leads to slipping and filming issues during cleaning, while increasing contact pressure to prevent slipping accelerates abrasion of the image holding member, reducing its lifetime.
Innovation Solution
The use of toner particles with a shape factor of 120 to 145 and hydrophobic inorganic oxide particles with a number average particle diameter of 30 nm to 80 nm, where the content of hydrophobic inorganic oxide particles is adjusted to satisfy the formula Q ≥ 160 − 12R, forming an aggregate layer that prevents toner slipping and reduces abrasion by maintaining a contact pressure of 9.8 mN/mm to 21.6 mN/mm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If toner with a nearly true spherical shape (high shape factor) is used, then image quality and transfer efficiency are improved, but cleaning efficiency deteriorates due to toner slipping and filming
Solution Approach 1:
The invention changes the physical and chemical parameters of the toner particles by controlling the shape factor to 110-130 (deviating from perfect sphere) and adding hydrophobic inorganic oxide particles with specific surface area and contact angle properties, thereby resolving the contradiction between image quality and cleaning efficiency
Solution Approach 2:
The invention creates a composite toner system by combining organic toner particles with inorganic oxide particles (silica, alumina, or titania) that have specific hydrophobic surface properties, where the inorganic particles prevent filming while the organic component maintains image quality
2Productivity
If contact pressure of the cleaning blade is increased to prevent toner slipping, then cleaning efficiency is improved, but the image holding member undergoes accelerated abrasion reducing its lifetime
Solution Approach 1:
The invention changes the surface properties of the toner particles by controlling shape factor and adding hydrophobic inorganic oxide particles, which modifies the friction characteristics between toner and cleaning blade, allowing effective cleaning at lower contact pressures (9.8-21.6 mN/mm) and thus preventing abrasion of the image holding member
3Duration of action of stationary object
If contact pressure of the cleaning blade is decreased to reduce abrasion, then the lifetime of the image holding member is extended, but cleaning efficiency deteriorates due to toner slipping
Solution Approach 1:
The invention uses composite toner particles containing hydrophobic inorganic oxide particles that create sufficient friction between toner and cleaning blade surface, enabling effective cleaning at low contact pressures and thus extending the lifetime of the image holding member while maintaining cleaning efficiency
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 enhances the cleaning efficiency of the image holding member, prevents filming, and extends the lifetime of the image holding member by effectively managing toner slipping and abrasion.
Implementation Method 1
toner that contains toner particles having a shape factor SF1 of 110 to 130 and hydrophobic inorganic oxide particles having a number average particle diameter of 30 nm to 80 nm
Implementation Method 2
a cleaning unit that has a cleaning blade which contacts with the surface of the image holding member at contact pressure of 9.8 mN/mm to 21.6 mN/mm, and removes toner remaining on the surface
Data Source
AI summary
An image forming apparatus includes an image holding member; a charging unit; an electrostatic charge image forming unit; a developing unit that accommodates an electrostatic charge image developer that contains toner particles having a shape factor SF1 of 120 to 145 and hydrophobic inorganic oxide particles having a number average particle diameter of 30 nm to 80 nm and satisfies the Formula (1), and develops the electrostatic charge image formed on the surface of the image holding member to form a toner image, by the electrostatic charge image developer; a transfer unit; and a cleaning unit that includes a cleaning blade which contacts with the surface of the image holding member at contact pressure of 9.8 mN/mm to 21.6 mN/mm, and removes toner remaining on the surface of the image holding member after transferring the toner image by the cleaning blade:Q≧160−12R (1).