Printing Coated Paper Ink Absorption and Mottling Control
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Solution Overview
Problem
Conventional offset printing coated papers used in ink-jet printing machines suffer from poor ink affinity, leading to mottling, low print density, and inadequate rubbing resistance, especially at high printing speeds.
Innovation Solution
A printing coated paper with a coating layer containing ground calcium carbonate of average particle diameter 0.1 to 0.28 μm and treated with a cationic resin and water-soluble multivalent cation salt, applied in a specific range to enhance ink absorption and print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional offset printing coated paper is used in ink-jet printing machine, then the paper has satisfactory ink absorption, but the surface affinity with ink is unsatisfactory causing mottling
Solution Approach 1:
The invention changes the surface parameters of the coated paper by applying a size press treatment solution containing cationic resin and water-soluble multivalent cation salt. This treatment modifies the surface chemistry and physical properties, improving ink affinity and preventing mottling while maintaining bulk ink absorption capabilities.
Solution Approach 2:
The size press treatment solution acts as an intermediary between the coated paper surface and the ink. The cationic resin and multivalent cation salt in the treatment solution create intermediate bonding sites that facilitate better ink adhesion to the paper surface, resolving the affinity problem.
2Productivity
If conventional coated paper is used for ink-jet printing, then the paper can be printed, but the print density of dye ink is markedly poor
Solution Approach 1:
The size press treatment changes the surface parameters of the coated paper, creating optimal conditions for dye ink absorption and fixation. The treatment solution components modify the surface energy and porosity, enabling better dye ink penetration and higher print density.
3Productivity
If conventional coated paper is used in ink-jet printing machine, then the paper can be printed at high speed, but the rubbing resistance with respect to printed area is poor
Solution Approach 1:
The size press treatment is applied in advance to the coated paper before printing. This preliminary action prepares the paper surface with enhanced binding properties, ensuring that the printed area gains sufficient rubbing resistance to withstand high-speed printing and subsequent handling.
4Reliability
If ground calcium carbonate with larger particle diameter is used in coating layer, then the offset printability is maintained, but the ink affinity and mottling suppression are insufficient
Solution Approach 1:
The invention changes the particle size parameter of ground calcium carbonate to a specific range (0.1 to 0.28 μm) that optimizes both offset printability and ink affinity. This parameter optimization allows the coating layer to maintain its offset printing performance while providing sufficient surface characteristics for ink adhesion and mottling suppression.
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 solution effectively suppresses mottling, improves print density, and enhances rubbing resistance in ink-jet printing, particularly at high speeds, while maintaining offset printability.
Implementation Method 1
the base paper is a treated base paper which has been subjected to size press using a treatment solution containing at least one member selected from a cationic resin and a water-soluble multivalent cation salt
Implementation Method 2
the at least one pigment in the coating layer is ground calcium carbonate having an average particle diameter in the range of from 0.1 to 0.28 μm
Data Source
AI summary
Provided is a printing coated paper which is advantageous not only in that the coated paper has offset printability and causes no mottling in the printed area even in ink jet printing, but also in that the coated paper exhibits excellent rubbing resistance with respect to the printed area and excellent print density of a dye ink. The task of the present invention is achieved by a printing coated paper having a coating layer comprised mainly of a pigment and a binder formed on at least one side of a base paper, wherein the base paper is a treated base paper which has been subjected to size press using a treatment solution containing at least one member selected from a cationic resin and a water-soluble multivalent cation salt, wherein the total applied amount per each side of the at least one member selected from a cationic resin and a water-soluble multivalent cation salt, in terms of the solids content, is in the range of from 0.1 to 5.0 g/m2, and wherein the at least one pigment in the coating layer is ground calcium carbonate having an average particle diameter of 0.1 to 0.28 μm, wherein the amount of the ground calcium carbonate having an average particle diameter of 0.1 to 0.28 μm contained in the coating layer is in the range of 60 parts by mass or more, relative to 100 parts by mass of the total of the pigment(s) in the coating layer.