Toner Binder Resin and Charge Control Agent for Image Quality
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Solution Overview
Problem
Existing toner technologies face challenges in achieving high image quality and low-temperature fixability while minimizing scattering, roughness, and selective development, particularly due to broad charge amount distribution and degradation of the line/solid ratio in electrostatic latent image development.
Innovation Solution
A toner and two-component developer are developed, utilizing a binder resin with a polyester unit and a charge control agent represented by a specific formula, where the binder resin includes aliphatic compounds with 30-102 carbon atoms, and the charge control agent is a pyrazolone monoazo metal compound, enhancing charge uniformity and interaction with the binder resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a charge control agent with high charging capability is used, then the charge amount of the toner is increased, but the charge amount distribution becomes broad causing scattering and roughness
Solution Approach 1:
The patent modifies the molecular structure parameters of the charge control agent by introducing a pyrazolone ring and specific substituent groups (formula [1]), which changes the charge generation mechanism to achieve both high charge amount and narrow distribution. This structural parameter change resolves the contradiction between charge quantity and distribution uniformity.
Solution Approach 2:
The patent combines the charge control agent with a specific binder resin system (polyester resin containing aliphatic polyhydric alcohol in 70-95 mol%) to create a composite toner material. This composite approach allows the charge control agent to function effectively while the binder resin provides structural integrity and controlled charge distribution, resolving the scattering and roughness issues.
2Temperature
If polyester resin with long-chain alkyl groups is used to improve low-temperature fixability, then the fixability is improved, but the charge amount decreases and line/solid ratio is degraded
Solution Approach 1:
The patent introduces aliphatic polyhydric alcohol groups (specifically 1,3-propanediol, 1,4-butanediol, or 1,5-pentanediol) at specific locations within the polyester resin structure. This local modification provides the necessary low-temperature fixability through hydrogen bonding while maintaining the overall charge control properties, thus resolving the contradiction between fixability and charge amount.
3Device complexity
If the same development contrast is used for broad charge distribution, then the development process is simplified, but selective development occurs and line/solid ratio is degraded
Solution Approach 1:
The patent changes the charge control agent's molecular parameters (formula [1] with specific substituents) to achieve a narrow charge amount distribution (standard deviation of 15% or less). This parameter change allows the use of uniform development conditions without selective development, as the charge distribution is sufficiently narrow to prevent size-based selective charging, thereby resolving the line/solid ratio degradation issue.
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 achieves improved low-temperature fixability, reduced scattering and roughness, and maintains a sharp charge amount distribution, thereby enhancing image quality and line/solid ratio stability.
Implementation Method 1
a charge control agent including a compound represented by formula [1]... the charge control agent is a pyrazolone monoazo metal compound... satisfactory in rise of electric charge
Implementation Method 2
the binder resin includes a resin having a polyester unit with at least one aliphatic compound condensed to the terminal thereof... the at least one aliphatic compound being selected from the group consisting of aliphatic monocarboxylic acids... and aliphatic monoalcohols
Implementation Method 3
the properties required for the toner include high charge amount and sharp distribution of charge amount... the use of these charge control agents allows toners relatively high in charge amount to be obtained
Data Source
AI summary
The present invention is a toner including a toner particle containing a binder resin and a charge control agent, wherein the binder resin includes a resin having a polyester unit with at least one aliphatic compound condensed to the terminal thereof, the at least one aliphatic compound being selected from the group consisting of aliphatic monocarboxylic acids each having 30 or more and 102 or less carbon atoms and aliphatic monoalcohols each having 30 or more and 102 or less carbon atoms; and the charge control agent includes a specific compound (a pyrazolone monoazo metal compound).