Liquid Developer Pigment System for Transfer Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid developers for electrophotographic image forming face challenges in achieving adequate image density and preventing transfer failure, particularly due to the electrical conductivity of carbon black and insufficient adjustment of electrical resistance when using copper phthalocyanine or yellow pigments.
Innovation Solution
A liquid developer comprising toner particles with a combination of carbon black, C.I. Pigment Brown 23 or C.I. Pigment Brown 25, and optionally C.I. Pigment Blue 15:3 and/or C.I. Pigment Yellow 74, 74, 155, 180, or 185, which maintains high pigment concentration without causing transfer failure by adjusting electrical resistance and ensuring proper hue and image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the concentration of carbon black is increased to ensure adequate image density, then image density is improved, but electrical resistance decreases causing transfer failure
Solution Approach 1:
The patent changes the chemical composition parameters of the pigment system by introducing specific brown pigments (C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25) in combination with carbon black. This compositional parameter change allows the system to achieve both high image density and adequate electrical resistance, as the brown pigments contribute to color strength while having different electrical properties than carbon black alone.
Solution Approach 2:
The patent creates a composite pigment system by combining carbon black with specific brown pigments (C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25) in defined ratios (40-80% carbon black, 20-60% brown pigment). This composite material approach allows the toner particles to benefit from both the high electrical resistance of the brown pigments and the high image density contribution of carbon black, thereby resolving the contradiction between image density and transfer quality.
2Manufacturing precision
If the particle size of toner particles is reduced to improve image quality, then image quality is improved, but more toner particles are needed to ensure adequate image density
Solution Approach 1:
The patent changes the pigment concentration parameter within toner particles by incorporating 20-60% by mass of brown pigments in combination with carbon black. This parameter change increases the color strength per unit mass of toner, allowing smaller particle sizes to deliver adequate image density, thus resolving the contradiction between image quality and toner quantity.
3Reliability
If copper phthalocyanine is used to adjust electrical resistance, then electrical resistance is improved, but hue adjustment is insufficient
Solution Approach 1:
The patent changes the pigment composition parameters by selecting specific brown pigments (C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25) that provide both adequate electrical resistance and proper black hue. The patent specifies that carbon black content should be 40-80% and brown pigment content should be 20-60%, creating a compositional parameter range that simultaneously satisfies both electrical resistance and hue requirements.
4Illumination intensity
If Solvent Brown 58 is used in combination with carbon black, then hue is improved, but the pigment migrates into insulating liquid causing transfer failure
Solution Approach 1:
The patent selects brown pigments (C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25) that are inherently suitable for liquid developer systems, avoiding the migration problem exhibited by Solvent Brown 58. These selected pigments maintain their position within toner particles and do not migrate into the insulating liquid, thereby preventing transfer failure while still providing the desired hue adjustment.
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 achieves high image quality with adequate image density and proper hue while preventing transfer failure, even at high pigment concentrations, by utilizing specific brown pigments that enhance electrical resistance and dispersibility within the resin.
Implementation Method 1
Carbon black used commonly as this black pigment, however, has electrical conductivity, which means that an increase of the concentration of carbon black causes the electrical resistance of the toner particles to decrease, resulting in a problem of occurrence of a transfer failure in electrophotographic image formation.
Implementation Method 2
the first pigment is carbon black, the second pigment is C.I. (color index) Pigment Brown 23 and/or C.I. Pigment Brown 25... not only satisfies an adequate image density and a proper hue but also prevents the problem of transfer failure
Data Source
AI summary
A liquid developer is characterized in that it includes toner particles and an insulating liquid, the toner particles include a resin and a pigment, the pigment includes a first pigment and a second pigment, the first pigment is carbon black, the second pigment is C.I. Pigment Brown 23 and/or C.I. Pigment Brown 25, and 20 to 60% by mass of the pigment is included relative to the toner particles.