Inkjet White-Ink Drying Layout for Low-Wettability Media
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Solution Overview
Problem
Aqueous pigment ink used in inkjet recording apparatuses tends to cause repelling and blotting on low-wettability recording media like plastic sheets due to insufficient drying of white ink, leading to image quality issues.
Innovation Solution
An inkjet recording apparatus with a specific arrangement of conveyance, application, and drying portions, using white ink with first resin particles having a minimum film formation temperature of 40°C to 80°C and non-white ink with second resin particles having a minimum film formation temperature of 80°C or less, along with controlled drying temperatures in each portion to ensure proper drying and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If white ink is applied to a recording medium with low wettability, then the wettability is improved, but blotting occurs due to insufficient drying
Solution Approach 1:
The drying process is segmented into two distinct stages: first drying (arranged between application and recording portions) and second drying (arranged after recording). The first drying removes solvent from white ink to prevent blotting before non-white ink is applied, while the second drying completes the drying process after image formation. This segmentation resolves the contradiction by providing targeted drying at appropriate process stages.
Solution Approach 2:
The first drying portion performs preliminary drying of white ink before the recording portion applies non-white ink. By removing solvent from white ink in advance, the recording medium surface is prepared to accept subsequent ink application without blotting, thus preventing the harmful effect before it occurs.
2Productivity
If high drying temperature is applied, then drying speed is improved, but resin particles form films prematurely causing blotting
Solution Approach 1:
The patent specifies precise temperature parameters for different drying stages: the first drying temperature is controlled to be not higher than 60°C (preferably 40-50°C) to prevent premature film formation, while the second drying temperature is set to 80-90°C to complete drying efficiently. This parameter control resolves the contradiction by matching temperature to process stage requirements.
Solution Approach 2:
The drying process uses periodic action with two distinct temperature phases: a lower temperature phase (first drying at ≤60°C) followed by a higher temperature phase (second drying at 80-90°C). This periodic temperature variation allows solvent removal without premature resin film formation, then completes drying at higher temperature safely.
3Ease of manufacture
If non-white ink is applied over wet white ink, then image formation is achieved, but abrasion resistance deteriorates
Solution Approach 1:
The first drying portion performs preliminary drying of white ink before non-white ink is applied by the recording portion. This preliminary solvent removal creates a stable base layer that prevents blotting during subsequent ink application and ensures proper adhesion, thereby maintaining abrasion resistance while enabling image formation.
Solution Approach 2:
By controlling the first drying temperature to not higher than 60°C, the patent prevents premature resin film formation while still removing sufficient solvent to establish a stable base. This parameter control allows non-white ink to be applied over properly prepared white ink, achieving both image formation and abrasion resistance.
4Ease of operation
If white ink is used as background layer, then wettability is improved, but drying time increases
Solution Approach 1:
The drying process is segmented into two efficient stages: first drying (removing bulk solvent at lower temperature to prevent blotting) and second drying (completing drying at higher temperature). This segmentation reduces total drying time compared to single-stage high-temperature drying, as each stage is optimized for its specific purpose.
Solution Approach 2:
The periodic two-stage drying process with distinct temperature phases (≤60°C followed by 80-90°C) efficiently removes solvent at optimal rates for each stage, reducing overall drying time while preventing the blotting that would occur with continuous high-temperature drying.
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
Prevents blotting and enhances abrasion resistance of images by optimizing the drying process, ensuring effective adhesion of inks to low-wettability media.
Implementation Method 1
The first drying portion is arranged downstream of the application portion with respect to the conveyance direction of the recoding medium and dries the white ink applied to the recoding medium by the application portion
Implementation Method 2
the drying temperature in the first drying portion is lower than the first minimum film formation temperature
Implementation Method 3
The second drying portion is arranged downstream of the recording portion with respect to the conveyance direction of the recoding medium and dries the non-white ink applied to the recoding medium by the recording portion
Implementation Method 4
the drying temperature in the second drying portion is equal to or higher than the first and second minimum film formation temperatures
Implementation Method 5
The white ink contains first resin particles with a minimum film formation temperature of 40°C or more but 80°C or less. The non-white ink contains second resin particles with a minimum film formation temperature of 80°C or less.
Data Source
Figure 1~2
Figure 3
AI summary
An inkjet recording apparatus (100) at least includes a conveyance portion (1), an application portion (2), a first drying portion (5), a recording portion (3), and a second drying portion (6). The first drying portion (5) dries white ink applied to a recoding medium (S) by the application portion (2). The recording portion (3) ejects non-white ink onto the recording medium (S) having passed through the first drying portion (5). The second drying portion (6) dries the non-white ink applied to the recoding medium (S) by the recording portion (3). The white ink contains first resin particles with a first minimum film formation temperature of 40°C to 80°C. The non-white ink contains second resin particles with a second minimum film formation temperature of 80°C or less. The drying temperature is, in the first drying portion (5), lower than the first minimum film formation temperature and, in the second drying portion (6), equal to or higher than the first and second minimum film formation temperatures.