Regular Paper Pretreatment for Inkjet Feathering and Bleeding Control
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Solution Overview
Problem
Inkjet printing on regular paper without a coat layer faces issues of image failure due to feathering, color bleeding, and poor rubfastness, with existing methods failing to achieve simultaneous improvement in image density, color saturation, and resistance to smearing.
Innovation Solution
Applying a pretreatment liquid containing a cationic polymer compound and a surfactant to the paper surface, combined with an inkjet recording ink that includes a water-dispersible colorant and a penetrating agent, to enhance the adhesion and saturation of the ink, while maintaining low surface tension for improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ink permeability is suppressed to decrease feathering, then feathering is reduced, but ink dryness becomes poor causing smear adhesion
Solution Approach 1:
A pretreatment liquid containing cationic polymer compound and surfactant is applied to the regular paper surface before inkjet printing. This preliminary action modifies the paper surface properties to control ink permeability and improve drying characteristics, resolving the contradiction between reducing feathering and preventing smear adhesion.
Solution Approach 2:
The invention changes the surface tension parameter of the pretreatment liquid to 20-30 mN/m through surfactant addition, and controls the molecular weight and charge density of the cationic polymer compound. These parameter changes optimize ink penetration control while maintaining surface adhesion, simultaneously reducing feathering and smear adhesion.
2Object-affected harmful factors
If ink permeability is increased to decrease color bleeding, then color bleeding is reduced, but image density decreases and back permeation increases
Solution Approach 1:
The pretreatment liquid creates local quality differences on the paper surface through cationic polymer compound deposition. The modified regions provide controlled ink reception properties that prevent color bleeding at boundaries while maintaining high image density in printed areas, and the low surface tension (20-30 mN/m) ensures proper ink distribution without excessive back permeation.
3Manufacturing precision
If treatment liquid containing fine particles is used to improve aggregation effect, then colorant aggregation is enhanced, but rubfastness deteriorates due to mechanical vulnerability
Solution Approach 1:
The invention extracts and eliminates the fine particles component from the pretreatment liquid formulation, retaining only the cationic polymer compound and surfactant. This removal of problematic fine particles prevents the formation of mechanically vulnerable accumulations on the paper surface, thereby maintaining high color saturation through colorant aggregation while significantly improving rubfastness.
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 achieves excellent image density, color saturation, and reduced feathering and bleeding, along with improved rubfastness, ensuring high-quality images with resistance to smearing and environmental durability.
Implementation Method 1
a colorless liquid containing silica fine particles is deposited to a recording medium, and then a non-aqueous recording liquid containing oil black is deposited thereto
Implementation Method 2
the pretreatment liquid has a static surface tension of 20 mN/m to 30 mN/m
Implementation Method 3
Increasing the ink permeability is being tried for solving the problem, namely, for decreasing the color bleeding
Data Source
AI summary
An image forming method of the present invention including applying a pretreatment liquid to a recording medium, and discharging an inkjet recording ink dropwise according to an image signal to form an image on the recording medium on which the pretreatment liquid has been applied, wherein the recording medium is regular paper which has no coat layer, the pretreatment liquid contains a cationic polymer compound, a surfactant A, water and a water-soluble organic acid, and the inkjet recording ink contains a water-dispersible colorant, a water-soluble organic solvent, a surfactant B, a penetrating agent and water, and wherein the pretreatment liquid has a static surface tension of 20 mN/m to 30 mN/m.