Black Ink Image Forming with UV Exposure to Limit Paper Waving
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet printing on cut sheets experiences waving due to moisture loss during drying, particularly with black ink containing carbon black, leading to deteriorated image density and gloss, and existing methods to address this often require additional ink tanks or heads, increasing cost and complexity.
Innovation Solution
An image forming device and method using black ink with specific resin combinations (Tg A < T i < Tg B ) and exposure to visible light or ultraviolet radiation with a wavelength of 700 nm or less to minimize moisture evaporation, balancing image density and drying properties while reducing waving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat drying is used to quickly evaporate water and solvent in ink, then drying speed is improved, but paper waving occurs due to moisture loss in the printed medium
Solution Approach 1:
The patent changes the drying method from thermal evaporation to photochemical drying. By using UV irradiation with specific wavelengths (365nm or 395nm) and controlling the resin glass transition temperature (50-150°C), the ink dries through photopolymerization rather than heat evaporation, eliminating paper waving while maintaining fast drying speed
Solution Approach 2:
The patent utilizes the phase transition of resins through controlled glass transition temperatures. By selecting resins with Tg of 50-150°C, the ink formulation transitions from a liquid state during printing to a solidified state during UV drying, enabling rapid drying without thermal expansion that causes paper waving
2Productivity
If black ink containing carbon black is heated and dried, then drying is achieved, but image density and gloss deteriorate due to carbon black exposure on the surface
Solution Approach 1:
The patent changes the drying mechanism from thermal to photochemical by using UV irradiation at 365nm or 395nm. This prevents carbon black particles from being exposed to heat that would cause them to migrate to the surface, thereby maintaining image density and gloss while achieving complete drying through photopolymerization of the resin
Solution Approach 2:
The patent replaces the thermal drying system with a photochemical drying system. Instead of using heat to evaporate solvents, UV light initiates photopolymerization of the resin, which binds the ink components together and solidifies the image without thermal movement of carbon black particles
3Stability of the object's composition
If composite inks without black ink are used to print on special paper, then paper waving is reduced, but achromatic portions are colored and cost increases
Solution Approach 1:
The patent uses a composite ink formulation containing carbon black pigment, water, organic solvent, and specific resins (with Tg of 50-150°C). This composite structure allows the ink to be dried via UV photopolymerization rather than heat evaporation, enabling the use of black ink without causing paper waving while maintaining color accuracy and reducing cost by eliminating the need for special paper types
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
Achieves high image density and gloss with minimal paper waving by controlling resin glass transition temperatures and using UV/visible light exposure, thus optimizing drying and image quality without additional hardware.
Implementation Method 1
a first resin (A) and a second resin (B) different from each other, and wherein the resins (A) and (B) satisfy the following relationship: Tg A < Ti < Tg B
Implementation Method 2
exposure to visible light or ultraviolet radiation with a wavelength of 700 nm or less to minimize moisture evaporation
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An image forming device (10;400;1000) includes a black ink applying device (410k;101) configured to apply a black ink to a recording medium, and an irradiator (54;301) configured to expose the recording medium onto which the black ink has been applied to visible light or ultraviolet radiation having a wavelength of 700 nm or less, wherein the black ink comprises water, an organic solvent, carbon black, a resin A, and a resin B, wherein the resin A and the resin B satisfy the following relationship: TgA < Ti < TgB, where TgA represents the glass transition temperature of the resin A, TgB represents the glass transition temperature of the resin B, and Ti represents the surface temperature of an image on the recording medium after the recording medium is exposed to the visible light or ultraviolet radiation.