Toner with Composite Resin for Low-Temperature Fixing and Anti-Blocking
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Solution Overview
Problem
Current toners face challenges in achieving low temperature fixing ability, anti-blocking properties, and preventing transfer white missing, particularly in high-speed devices and high temperature humidity environments, while maintaining stability and image quality.
Innovation Solution
A toner formulation containing a non-crystalline polyester resin with a diol component, trivalent or higher acid, and a urethane or urea bond, which has a glass transition temperature (Tg1st) of 25° C. to 50° C. and a TMA compressive deformation rate of 10% or lower at 50° C. under 70% relative humidity, ensuring anti-blocking and low temperature fixing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If glass transition temperature (Tg) of toner binder is lowered to achieve low temperature fixing, then fixing temperature is reduced, but aggregation (blocking) of powder occurs and anti-blocking property deteriorates
Solution Approach 1:
The invention uses a composite binder resin system comprising a non-crystalline polyester resin (main component) and a crystalline resin (auxiliary component). This composite structure allows the non-crystalline resin to provide low-temperature fixing ability through its low Tg, while the crystalline resin maintains structural integrity and prevents aggregation at low temperatures, thus resolving the contradiction between low fixing temperature and anti-blocking property.
Solution Approach 2:
The invention precisely controls the Tg of the non-crystalline polyester resin within a specific range (20°C to 60°C, preferably 30°C to 50°C) and limits the crystalline resin content to 5-50 mass% of the total binder resin. These parameter optimizations ensure the toner achieves both low-temperature fixing capability and sufficient anti-blocking performance, transforming the qualitative trade-off into a quantitative balance.
2Temperature
If glass transition temperature (Tg) of toner binder is lowered to achieve low temperature fixing, then fixing temperature is reduced, but toner deposits on carrier and photoconductor causing filming
Solution Approach 1:
The crystalline resin component in the composite binder system provides structural support and prevents excessive softening at low temperatures, thereby preventing toner deposition on carriers and photoconductors. The non-crystalline polyester resin enables low-temperature fixing, while the crystalline resin acts as a stabilizer to prevent filming, resolving the contradiction between low fixing temperature and anti-filming property.
3Temperature
If glass transition temperature (Tg) of toner binder is lowered to achieve low temperature fixing, then fixing temperature is reduced, but shelf stability of fixed image is degraded
Solution Approach 1:
The crystalline resin in the composite binder system maintains dimensional stability and prevents image melting and displacement during storage, while the non-crystalline polyester resin provides low-temperature fixing capability. This composite structure resolves the contradiction between low fixing temperature and shelf stability by dividing functional roles between the two resin types.
4Reliability
If crystalline resin is used as toner binder to achieve anti-blocking and low temperature fixing, then anti-blocking property is improved, but hot offset is caused due to lack of elasticity
Solution Approach 1:
The non-crystalline polyester resin with low Tg (20-60°C) provides elasticity and flexibility to the toner, preventing hot offset by allowing the toner to conform to the substrate without excessive rigidity. The crystalline resin provides anti-blocking properties. Together, they resolve the contradiction between anti-blocking performance and hot offset prevention by balancing structural support with flexibility.
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 achieves paradoxical characteristics of anti-blocking, anti-filming, and low temperature fixing, preventing transfer white missing, while maintaining heat-resistant storage stability and image quality.
Implementation Method 1
the toner has Tg1st of 25° C. to 50° C.; wherein Tg1st is glass transition temperature of the toner for first heating
Implementation Method 2
the toner has a TMA compressive deformation rate (TMA %) of 10% or lower at 50° C. under a condition having relative humidity of 70%
Data Source
AI summary
To provide a toner, which contains a colorant, a binder resin, and a releasing agent, wherein the toner satisfies the following (a) to (c): (a) the toner contains at least a polyester resin as the binder resin; (b) the toner has Tg1st of 25° C. to 50° C.; and (c) the toner has a TMA compressive deformation rate (TMA %) of 10% or lower at 50° C. under a condition having relative humidity of 70%, wherein the Tg1st is glass transition temperature of the toner for first heating, as the toner is measured by a DSC system (a differential scanning calorimeter).