Toner Set Charge Stability via External Additive Optimization
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Solution Overview
Problem
Conventional toners face challenges in maintaining stable charging ability and image quality, particularly in varying environmental conditions, leading to issues like fogging and reduced printing performance due to variations in charge amount and mechanical stress during the printing process.
Innovation Solution
A toner set comprising yellow, cyan, and magenta toners with specific charge amount and variation ranges, achieved through the use of external additives like silica and titanium oxide particles, and a frictional charge treatment process to ensure consistent charging levels and reduced variations, resulting in improved fine line reproducibility and color stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional external additives are used to improve charge stability and fluidity, then toner particle surface properties are enhanced, but charge rising property deteriorates in severe environments
Solution Approach 1:
The patent changes the particle size parameters of external additives, using ultrafine particles (0.1-10 μm) instead of conventional larger particles. This parameter change enables both improved charge stability and maintained charge rising property by increasing surface area and contact efficiency with charge members.
Solution Approach 2:
The patent uses composite external additives comprising multiple materials (silica, titanium oxide, zinc oxide) with different properties. This composite approach combines the charge stability benefits of inorganic particles with the charge rising properties of organic compounds, resolving the contradiction between stability and early-stage performance.
2Productivity
If continuous printing is performed to increase productivity, then output increases, but external additives bury into or detach from toner surfaces causing charge instability
Solution Approach 1:
The patent applies preliminary surface treatment to toner particles before external additive addition, creating a prepared surface that better anchors the ultrafine external additives. This preliminary action prevents additive burial and detachment during continuous printing, maintaining charge stability across high volumes.
Solution Approach 2:
The patent creates a continuous protective layer of external additives on toner surfaces that remains stable throughout continuous printing operations. This continuous coverage ensures consistent charging performance from the first print to the thousandth print, eliminating charge instability during high-volume production.
3Manufacturing precision
If toner charge amount is increased to improve development property, then image quality improves, but variations in charge amount increase causing fogging and toner scattering
Solution Approach 1:
The patent optimizes the particle size distribution parameters of external additives, using a specific range (0.1-10 μm) with particular emphasis on the 1-5 μm subset. This parameter optimization increases charge amount while the uniform size distribution ensures consistent charging across all particles, reducing variations and preventing fogging.
Solution Approach 2:
The patent applies external additives with specific local properties (ultrafine size, high surface area) directly to toner surfaces where charging occurs. This localized quality enhancement ensures uniform charge distribution across all toner particles, improving image quality while maintaining charge consistency through controlled surface modification.
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 toner set achieves excellent fine line reproducibility and color stability by maintaining consistent charge levels and reduced variations, enhancing printing performance even in severe environmental conditions.
Implementation Method 1
external additives, such as inorganic particles and organic particles having a particle diameter lower than that of colored resin particles (toner particles), are generally attached and added onto the surface of toner particles (external addition)
Implementation Method 2
a toner is charged by contact with charge members such as a carrier and a blade
Data Source
AI summary
There is provided a toner set including a yellow toner, a cyan toner and a magenta toner, the toners each comprising an external additive and colored resin particles comprising a binder resin, a colorant and a charge control agent. An absolute value of an average of q/d for any of the yellow, cyan and magenta toners is expressed by charge amount q (fC) and particle diameter d (μm). It is obtained by measurement using an electric field detachment-type charge amount distribution measurement device. It is in a range of 2.0 to 6.5 fC/10 μm, and a standard deviation (SD) of q/d is 13 fC/10 μm or less. A difference between average values of q/d for any two of the yellow, cyan and magenta toners is 2.0 fC/10 μm or less. A difference (ΔSD) between standard deviations of q/d for the two toners is 5.0 fC/10 μm or less.