Inkjet Treatment Liquid Coating for Uniform Image Density
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Solution Overview
Problem
Image density unevenness occurs due to coating unevenness of a treatment liquid applied to a permeable substrate, which is exacerbated by increased transportation speed, particularly when using a coating roller in image recording methods involving ink jet application.
Innovation Solution
An image recording method that applies a treatment liquid with specific viscosity and coating roller diameter parameters, using an organic acid salt as an aggregating agent, and controlling the mass ratio of the treatment liquid and ink application to suppress density unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transportation speed of the permeable substrate is increased, then productivity is improved, but coating unevenness of the treatment liquid occurs leading to density unevenness in the image
Solution Approach 1:
The patent applies parameter changes by optimizing the viscosity of the treatment liquid to a specific range (10-100 mPa·s) and controlling the coating roller diameter (50-200 mm) to achieve a balance between coating uniformity and high-speed transportation capability. This parameter optimization resolves the contradiction by enabling both improved productivity and maintained manufacturing precision.
2Reliability
If the viscosity of the treatment liquid is increased, then coating roller retention is improved, but coating unevenness increases due to difficulty in separation from the roller surface
Solution Approach 1:
The patent resolves this contradiction through parameter changes by defining an optimal viscosity range (10-100 mPa·s) for the treatment liquid. This specific viscosity range ensures sufficient retention on the coating roller while maintaining easy separability, thereby achieving both reliable coating application and uniform coating distribution without density unevenness.
3Device complexity
If the coating roller diameter is decreased, then device complexity is reduced, but the position variation in rotation axis direction increases causing coating unevenness
Solution Approach 1:
The patent applies parameter changes by specifying an optimal coating roller diameter range (50-200 mm) that balances device simplicity with coating precision. This diameter range minimizes position variation during rotation while maintaining practical device dimensions, thereby resolving the contradiction between reduced device complexity and maintained manufacturing precision.
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 effectively suppresses density unevenness by limiting the viscosity of the treatment liquid and coating roller diameter within defined ranges, ensuring uniform image quality even at higher transportation speeds.
Implementation Method 1
a treatment liquid applying step of applying a treatment liquid containing water and an aggregating agent for aggregating components in an ink to the permeable substrate
Implementation Method 2
a step of applying a treatment liquid containing water and an aggregating agent to a permeable substrate to be transported, with a coating roller
Implementation Method 3
a step of applying an ink containing water, a water-soluble organic solvent, a colorant, and a resin to a region of the permeable substrate, which has been coated with the treatment liquid, by an ink jet method
Data Source
AI summary
An image recording method includes a step of applying a treatment liquid containing water and an aggregating agent to a permeable substrate to be transported, with a coating roller, and a step of applying an ink containing water, a water-soluble organic solvent, a colorant, and a resin to a region of the permeable substrate, which has been coated with the treatment liquid, by an ink jet method to record an image, in which, in a case where a diameter of the coating roller, expressed in mm unit, is defined as y and a viscosity of the treatment liquid at 25° C., expressed in mPa·s unit, is defined as x, x is 5 to 100 and a value of y−25 ln(x) is 90 to 160.