Toner Composition for Cleanerless Printers
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Solution Overview
Problem
Cleanerless systems in printers face issues with toner deterioration, leading to poor transferability, embedding of external additives, and the occurrence of development ghosts and fixation tailing due to stress applied during charging and recovery steps, which affect image quality and stability over long-term use.
Innovation Solution
A toner with specific properties, including a softening point of 110° C to 140° C and specific integrated stress values measured using a tack tester, combined with a binder resin containing a vinyl resin and an amorphous polyester with monomer units derived from linear aliphatic dicarboxylic acids, to enhance adhesiveness and durability, reducing toner deterioration and improving transferability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a cleanerless system is adopted to reduce printer size, then the size of the image-forming apparatus is reduced, but toner deterioration occurs leading to poor transferability and development ghosts
Solution Approach 1:
The patent modifies the chemical composition parameters of the binder resin, specifically incorporating polyamide resin with controlled molecular weight (peak molecular weight 3,000-10,000) and using specific copolymer ratios (styrene-acrylate copolymer with 40-80 mass% styrene component). These parameter changes enhance toner adhesion and reduce deterioration during the charging and recovery steps in cleanerless systems, thereby maintaining transferability while enabling compact design.
Solution Approach 2:
The patent employs a composite binder resin system combining multiple resin components: styrene-acrylate copolymer, polyamide resin, and optionally other resins. This composite material approach creates synergistic effects where each component contributes specific properties - the styrene-acrylate copolymer provides adhesion, the polyamide resin provides durability and controlled melting characteristics. This composite structure enables the toner to withstand the stress of cleanerless operation while maintaining transferability.
2Volume of moving object
If film fixing is adopted to downsize the fixing unit, then the fixing unit size is reduced, but toner requires improved adhesiveness to prevent fixation tailing
Solution Approach 1:
The patent optimizes the melting point parameters of the binder resin to 70-90°C through selective resin composition and molecular weight control. This parameter change ensures the toner becomes sufficiently adhesive during the brief high-temperature film fixing process to prevent fixation tailing, while maintaining stability during normal operation. The controlled softening behavior at specific temperature thresholds enables effective adhesion in compact fixing units.
Solution Approach 2:
The patent utilizes periodic thermal action during film fixing where the toner is rapidly heated to melting temperature range (70-90°C) for brief periods during the fixing cycle. This periodic thermal treatment creates transient high adhesiveness exactly when needed during transfer, then allows cooling and solidification. The cyclic heating-cooling process enables strong bonding in the compact fixing unit without requiring continuous high temperature.
3Temperature
If toner softening point is lowered to improve low-temperature fixing, then fixing temperature is reduced, but toner brittleness increases leading to cracking under stress
Solution Approach 1:
The patent uses a composite resin system where styrene-acrylate copolymer and polyamide resin work synergistically. The styrene-acrylate copolymer provides flexibility and crack resistance, while the polyamide resin contributes to adhesion and controlled melting. This material composition enables the toner to maintain flexibility and resist brittleness even at lower softening points (70-90°C), preventing cracking during the charging and recovery steps while enabling low-temperature fixing.
Solution Approach 2:
The patent carefully controls the molecular weight parameters of the polyamide resin (peak molecular weight 3,000-10,000) and the copolymer composition ratios to achieve optimal balance between softening point and brittleness. By adjusting these parameters, the toner maintains sufficient molecular chain entanglement and intermolecular forces to prevent cracking, while the overall composition enables lower softening temperature for energy-efficient fixing.
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 effectively suppresses development ghosts and fixation tailing, maintaining image quality and stability over long-term use by ensuring toner adhesiveness and flowability, even under stress conditions.
Implementation Method 1
wherein a softening point of the toner is at least 110° C. and not more than 140° C.
Implementation Method 2
a binder resin, an amorphous polyester, and a colorant
Implementation Method 3
an integrated value f1 for stress of the toner is not more than 10 g·m/sec, as measured using a tack tester
Data Source
AI summary
A toner having a toner particle containing a binder resin, an amorphous polyester, and a colorant, wherein a softening point of the toner is at least 110° C. and not more than 140° C.; an integrated value f1 for stress of the toner is not more than 10 g·m/sec, as measured using a tack tester, with a temperature for a probe end being 150° C. and a press holding time being 0.01 seconds; and an integrated value f2 for stress of the toner is at least 30 g·m/sec, as measured using a tack tester, with a temperature for a probe end being 150° C. and a press holding time being 0.1 seconds.