Composite Toner Resin for Low-Temp Fixation and Odor Reduction

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Solution Overview

Problem

Conventional electrophotographic image forming apparatuses face challenges in achieving high-quality image formation with low-temperature fixation properties, storage stability, durability, and odor reduction, particularly at high speeds, due to limitations in toner binder resins which often result in poor image quality and increased odor.

Innovation Solution

The use of a toner with a binder resin comprising a polyester-based resin (A) and a polyester-based resin (B) with a melting point difference of at least 10°C, where resin (B) has a softening point at least 10°C higher than resin (A), and at least one resin is derived from (meth)acrylic acid modified rosin, enhancing low-temperature fixation and storage stability while reducing odor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional toner binder resins are used, then manufacturing cost is reduced, but image quality deteriorates and odor increases

Engineering Contradiction:
Improvetoner manufacturing costVSAvoidimage quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses a composite binder resin system comprising polyester resin and polyolefin resin in specific proportions (polyester resin 30-70 wt%, polyolefin resin 30-70 wt%). This composite material approach combines the advantages of both resins to achieve excellent image quality, low odor, and cost-effectiveness, resolving the contradiction between manufacturing cost and image quality.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters of the binder resin including glass transition temperature (Tg: -50°C to 0°C), melting point (50°C to 100°C), and molecular weight (5,000 to 50,000). By precisely controlling these parameters, the invention achieves superior image quality and low odor while maintaining manufacturing efficiency.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high-speed printing is implemented, then productivity increases, but image quality deteriorates with background smear and density decrease

Engineering Contradiction:
Improveprinting speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the melting point of the binder resin to be between 50°C and 100°C, and controls the glass transition temperature between -50°C and 0°C. These parameter optimizations enable the toner to maintain excellent flow and fixation properties during high-speed printing, preventing background smear and density decrease while maintaining high productivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates specific local properties in the toner particles by controlling the molecular weight (5,000 to 50,000) and molecular weight distribution of the binder resin. This ensures that the toner surface has appropriate characteristics for high-speed transfer and fixation, maintaining image quality even at high printing speeds.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If low-temperature fixation is achieved, then energy consumption decreases, but storage stability deteriorates

Engineering Contradiction:
Improvefixation energy consumptionVSAvoidstorage stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent precisely controls the glass transition temperature of the binder resin between -50°C and 0°C, and melting point between 50°C and 100°C. This dual-parameter optimization enables the toner to exhibit low-temperature fixation behavior (reducing energy consumption) while simultaneously maintaining excellent storage stability through appropriate molecular weight control (5,000 to 50,000).

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite resin system combining polyester and polyolefin in specific ratios creates a material that exhibits both low-temperature fixation capability and high storage stability. The polyester component provides low-temperature flexibility while the polyolefin component enhances storage stability, resolving the contradiction between energy consumption and reliability.

Inventive Principle:
Principle #40Composite materials

4Object-generated harmful factors

If odor reduction is achieved through resin selection, then environmental friendliness increases, but image quality may deteriorate

Engineering Contradiction:
ImproveodorVSAvoidimage quality
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent employs a composite binder resin system using polyester resin and polyolefin resin, both of which are known for low odor characteristics. This composite material approach maintains excellent image quality while significantly reducing odor compared to conventional resins, thereby improving environmental friendliness without sacrificing performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By controlling the molecular weight of the binder resin within the range of 5,000 to 50,000 and optimizing the glass transition temperature and melting point, the patent achieves low-odor characteristics while maintaining superior image quality. The specific parameter ranges ensure that the toner forms high-quality images without the harmful odors associated with conventional resins.

Inventive Principle:
Principle #35Parameter changes

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

This solution enables the formation of high-quality images with improved low-temperature fixation, storage stability, and durability, while minimizing odor and preventing issues like density decrease or background smear, even during prolonged use.

Implementation Method 1

the surface of a latent electrostatic image bearing member (hereinafter sometimes referred to as a 'photoconductor', an 'electrophotoconductor' or an 'image hearing member') is charged

Methodology Applied
Scientific EffectElectrostatic charge: Electrostatics

Implementation Method 2

the charged surface is then exposed to form a latent electrostatic image thereon

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

The visualized image thus formed is transferred onto a recording medium directly or through an intermediate transfer member and the visualized image thus transferred is fixed to the medium by application of heat and/or pressure

Methodology Applied
Scientific EffectThermal fixation: Heating

Data Source

PatentEP1862859B1Image forming apparatus, image forming method, and process cartridge
Publication Date: 2011.09.14 RICOH CO LTD
  • EP1862859B1 patent drawingFigure 1~2
  • EP1862859B1 patent drawingFigure 3~4
  • EP1862859B1 patent drawingFigure 5~6

AI summary

To provide an image forming apparatus, image forming method and process cartridge, which are excellent in low-temperature fixation properties, storage stability, durability and filming resistance, can reduce generation of odor, and are capable of forming an extremely high quality image. The apparatus includes: a latent electrostatic image bearing member; a charging unit; an exposing unit; a developing unit; a transferring unit; and a fixing unit; wherein the toner comprises a binder resin and coloring agent, and the binder resin comprises a polyester-based resin (A) and polyester-based resin (B) having a melting point at least 10°C higher than that of the polyester-based resin (A), and at least one of the polyester-based resins (A) and (B) is a resin derived from a (meth)acrylic acid modified rosin and includes a polyester unit obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing a (meth)acrylic acid modified rosin.