Hot Melt Ink Dot Size Control via Wax Thermal Hysteresis

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Solution Overview

Problem

Conventional hot melt ink compositions require external treatment to achieve desired dot sizes and image quality, increasing manufacturing costs and complexity.

Innovation Solution

A hot melt ink composition comprising waxes with a freezing point of 20° C. to 45° C. and a melting point of at least 35° C., primarily consisting of 50 wt % or more wax, which forms dots with larger diameters without external treatment, using amide alcohol, urethane, ether, or ester waxes, and optionally including colorants, tackifiers, resins, plasticizers, antioxidants, and dispersants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional hot melt ink compositions are used, then the ink can be printed, but external treatment is required to achieve desired dot sizes and image quality

Engineering Contradiction:
Improvedot size controlVSAvoidexternal treatment process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The hot melt ink composition self-regulates its dot size through the inherent thermal properties of the wax components. The specific freezing point range (20-45°C) and melting point (≥35°C) create a thermal hysteresis effect that automatically controls dot expansion and final size without requiring external treatment processes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the thermal parameters of the ink composition by selecting waxes with specific freezing points (20-45°C) and melting points (≥35°C). This parameter optimization allows the ink to form dots of desired size through controlled phase changes during printing and drying, eliminating the need for external treatment.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If external treatment is applied to achieve desired dot sizes, then dot size control is improved, but manufacturing costs increase

Engineering Contradiction:
Improvedot size controlVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The ink composition performs the dot size control function internally through its formulated wax components with specific thermal properties. This self-regulating mechanism eliminates the need for costly external treatment processes while maintaining precise dot size control.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention extracts and utilizes the thermal hysteresis effect inherent in the wax composition to achieve dot size control. By taking advantage of the natural difference between freezing and melting points of the selected waxes, the system eliminates the need for separate external treatment steps.

Inventive Principle:
Principle #2Taking out (Extraction)

3Shape

If conventional hot melt inks are used, then printing can be performed, but larger dot diameters require external treatment

Engineering Contradiction:
Improvedot diameterVSAvoidexternal treatment process
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The invention optimizes the thermal parameters of the ink by selecting waxes with freezing points in the range of 20-45°C and melting points of at least 35°C. This parameter selection enables the ink to form dots with diameters of at least 85 μm through controlled phase changes without requiring external treatment processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transitions of the wax components during printing and drying. The specific melting point (≥35°C) and freezing point (20-45°C) create a thermal window that allows the ink to flow and form larger dots during heating, then solidify to maintain the desired dot diameter without external intervention.

Inventive Principle:
Principle #36Phase transitions

4Manufacturing precision

If higher print resolution is used to compensate for smaller dots, then image quality improves, but manufacturing complexity increases

Engineering Contradiction:
Improveimage qualityVSAvoidprint resolution requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the physical parameters of the ink composition to achieve larger dot diameters (≥85 μm) through optimized wax thermal properties. This parameter change in dot size reduces the required print resolution to achieve acceptable image quality, thereby reducing manufacturing complexity.

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

The composition achieves increased dot size and improved image quality without external treatment, reducing manufacturing costs and complexity by forming dots with an average diameter of at least 15% larger than conventional inks, enhancing visual and machine-readable contrast and reducing print resolution needs.

Implementation Method 1

Hot melt inks are a solid at ambient temperature and a liquid at temperatures above ambient temperature. During printing, the ink is typically heated until it becomes a liquid which is then ejected through a printhead onto a substrate.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The ink can solidify on the substrate at ambient temperature.

Methodology Applied
Scientific EffectFreezing: Freezing

Data Source

PatentUS9410051B2Hot melt inks
Publication Date: 2016.08.09 MARKEM IMAJE CORP

AI summary

This disclosure includes a hot melt ink composition that includes at least one wax having a freezing point of from about 20° C. to about 45° C. and a melting point of at least about 35° C., and at least one colorant. The composition includes at least about 50 wt % of the at least one wax. This disclosure also relates to a printing process using such a composition and a product containing such a composition.