Inkjet Recording Medium Backside Layer Curl Reduction
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Solution Overview
Problem
Aqueous inkjet recording media often exhibit curl due to differential moisture absorption, leading to unreliable printing and feeding issues in printers, as well as potential dust formation and delamination during manufacturing and mounting.
Innovation Solution
A porous inkjet recording medium with a support coated on one side with an ink-receiving layer and on the opposite side with a backside layer comprising at least 50% fine inorganic particles and a binder, and a non-porous outer layer primarily consisting of polymeric material, which reduces curl propensity and enhances backside integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a back coating is applied to reduce curl, then curl propensity is reduced, but reliable picking and feeding by printer transport mechanism remains problematic
Solution Approach 1:
The patent applies different coating characteristics to different regions: the back coating is designed with specific properties (low static coefficient of friction, controlled porosity) to enable reliable picking and feeding, while the front coating maintains image quality. This localized optimization resolves the contradiction by making each region serve its specific function rather than using a uniform coating throughout.
Solution Approach 2:
The patent modifies key parameters of the back coating including static coefficient of friction (0.9 or less), porosity, and binder composition to simultaneously achieve curl reduction and reliable transport. By carefully controlling these parameters, the back coating becomes effective at both reducing curl and enabling reliable picking and feeding operations.
2Ease of manufacture
If binder amount in backside layer is low, then manufacturing cost is reduced, but transport reliability deteriorates under low temperature and low humidity conditions
Solution Approach 1:
The patent optimizes the binder content parameter in the back coating to a specific range that balances manufacturing cost with transport reliability. The binder amount is controlled to maintain adequate adhesion and friction properties for reliable picking and feeding while avoiding excessive material usage that would increase cost and require additional dilution.
3Reliability
If binder amount in backside layer is significantly increased, then transport reliability is improved, but viscosity of coating composition increases requiring dilution and increased drying requirement
Solution Approach 1:
The patent identifies and controls the binder content parameter within an optimal range that ensures adequate transport reliability without causing excessive viscosity. This parameter control avoids the need for significant dilution and reduces drying requirements, simplifying the manufacturing process while maintaining reliable picking and feeding performance.
4Manufacturing precision
If front coating weight is increased to improve image quality, then image quality is improved, but curl propensity increases due to asymmetric moisture absorption
Solution Approach 1:
The patent applies a back coating that acts as a counterweight to the front coating's moisture absorption characteristics. The back coating is designed with complementary properties to balance the overall moisture absorption differential across the media, thereby reducing curl while allowing the front coating to maintain optimal weight for image quality.
Solution Approach 2:
The patent differentiates the functional requirements of the two coatings: the front coating is optimized for image quality with appropriate weight and composition, while the back coating is specifically designed to balance moisture absorption and reduce curl. This localized functional differentiation allows each coating to be optimized for its specific purpose without compromising the other.
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 provides a glossy, flat printing medium with improved reliability in picking and feeding, reduced curl under various conditions, and prevents dusting and delamination during manufacturing and printing.
Implementation Method 1
Ink-receptive media are in dynamic equilibrium with the environment with regard to moisture. Hydrophilic materials tend to expand as moisture is absorbed. Differential expansion within a multi-layered material will result in curl.
Implementation Method 2
Aqueous inks are often the most suitable type for the process of desktop printing
Data Source
AI summary
The present invention is directed to an image-recording medium comprising a paper support and, coated on one side of the support, in order: a lower ink-receiving layer, an upper gloss layer and, coated on the opposite side of the support, an inner layer comprising at least 75% by weight of fine inorganic particles and a binder, and an outer layer substantially consisting of a polymeric material. Another aspect of the present invention relates to an inkjet printing process.