Water-based Ink Drying for Reverse Void Printing
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Solution Overview
Problem
In void printing, the ink in already printed images prevents new ink from drying properly, leading to decreased abrasion resistance and the risk of ink adhering to conveyance mechanisms due to insufficient heating of ink portions during reverse sheet conveyance.
Innovation Solution
A recording method and device that discharge water-based recording ink with a resin-dispersed pigment, fine resin particles, and a water-soluble organic solvent onto a recording medium, where the ink is heated and read to determine if the first image is correctly recorded; if not, the medium is conveyed in reverse to record a second image over the first, using a solvent with low vapor pressure and surface tension for quick drying and improved abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If void printing is performed by conveying the recording medium in reverse direction, then the first image can be corrected, but the ink in already printed portions prevents new ink from drying properly
Solution Approach 1:
The patent changes the physical and chemical parameters of the ink formulation, specifically using a water-based ink with controlled surface tension (20-35 mN/m) and vapor pressure (0.03 hPa or less at 20°C), to enable proper drying during reverse conveyance void printing
Solution Approach 2:
The patent utilizes the phase transition of water-based solvent from liquid to vapor through controlled evaporation, ensuring the ink dries properly even when the medium is conveyed in reverse direction, by carefully selecting solvents with appropriate vapor pressure characteristics
2Reliability
If the recording medium is conveyed in reverse direction for void printing, then printing errors can be corrected, but ink may adhere to conveyance mechanisms due to insufficient heating
Solution Approach 1:
The patent modifies the ink's vapor pressure and surface tension parameters to ensure sufficient volatility and drying speed, preventing ink from adhering to conveyance mechanisms during reverse direction transport
Solution Approach 2:
The water-based solvent acts as an intermediary that facilitates controlled evaporation and drying, preventing direct contact and adhesion between the ink pigment and the conveyance mechanism surfaces
3Productivity
If conventional ink is used for overlapping images, then the printing process can be completed, but abrasion resistance decreases due to improper drying
Solution Approach 1:
The patent optimizes the ink composition parameters including surface tension (20-35 mN/m) and vapor pressure (0.03 hPa or less at 20°C) to achieve proper drying and fixation of overlapping images, thereby maintaining high abrasion resistance
Solution Approach 2:
The patent uses a composite ink formulation containing water-based solvent, resin, and pigment, where the specific combination of water-soluble organic solvents with controlled vapor pressure creates a matrix that ensures both drying quality and mechanical strength of the printed image
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 method and device enable quick ink drying and excellent abrasion resistance for overlapping images, reducing the risk of ink adherence to conveyance mechanisms.
Implementation Method 1
heating the recording medium or the water-based recording ink adhered to the recording medium with a heater to record a first image
Implementation Method 2
A content of substances having a vapor pressure of 0.03 hPa or less at 20° C. in the water-based recording ink relative to a total mass of the water-based recording ink is 10 mass % or less
Implementation Method 3
a surface tension of the water-based recording ink is 30 mN/m or less
Data Source
AI summary
A recording method includes: recording a first image on a recording medium; reading the first image to determine whether the first image is correctly recorded; and when the first image is determined as not being correctly recorded, recording a second image over the first image. The water-based recording ink includes a water-soluble organic solvent which is at least one selected from the group consisting of a glycol ether and a diol compound having six to eight carbon atoms and two hydroxyl groups, at least one of the two hydroxyl groups not being bonded to a terminal of a carbon chain of the diol compound. A content of substances having a vapor pressure of 0.03 hPa or less at 20° C. in the water-based recording ink is 10 mass % or less and a surface tension of the water-based recording ink is 30 mN/m or less.