Diagnostic Sheet for Detecting Colorless Precoat Jet Errors
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Solution Overview
Problem
Inconsistent deposition of primer or precoat solutions in aqueous ink jet printing systems leads to poor print quality and de-inkability, particularly on uncoated porous media, necessitating a method to detect and correct missing or misdirected jets.
Innovation Solution
A diagnostic system using a printhead to deposit a colorless precoat solution on a diagnostic sheet with a color-responsive layer, which changes color upon contact, allowing for detection of missing or misdirected jets through an image scanner, enabling adjustments to printhead operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a colorless precoat solution is deposited on uncoated porous media, then print quality improves by preventing ink absorption, but detection of missing or misdirected jets becomes difficult due to the solution's colorlessness
Solution Approach 1:
The patent applies a colorimetric indicator layer on the diagnostic sheet that changes color upon contact with the precoat solution. This allows the invisible colorless precoat solution to become visible through color change, enabling detection of missing or misdirected jets while maintaining the solution's non-interference with actual print quality.
2Manufacturing precision
If a primer layer is applied to reduce ink absorption into porous media, then image quality improves, but ink image removability for recycling becomes easier
Solution Approach 1:
The patent segments the coating system into two distinct layers: a primer layer applied to the porous media to prevent ink absorption and maintain image quality, and a separate colorimetric indicator layer on the diagnostic sheet for detection purposes. This segmentation allows the primer to fulfill its quality-enhancing function while the indicator layer provides the detection capability without interfering with recyclability.
3Measurement precision
If diagnostic sheets with color-responsive layers are used to detect precoat solution deposition, then jetting errors can be identified, but the system complexity increases
Solution Approach 1:
The diagnostic sheet performs self-detection through the colorimetric indicator layer that automatically changes color upon contact with the precoat solution. This self-service mechanism eliminates the need for complex external sensing equipment or sophisticated detection systems, achieving accurate jet deposition detection while minimizing system complexity.
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
Ensures uniform precoat application, improving print quality and de-inkability by identifying and correcting jetting errors, thereby enhancing the effectiveness of inkjet printing systems.
Implementation Method 1
a layer of material disposed on the first surface of the substrate, where the layer of material changes color after contacting the precoat solution
Data Source
AI summary
A diagnostic system for measuring inkjet printing system performance includes a printhead that deposits a colorless precoat solution from one or more of a plurality of ejector jets. The diagnostic system includes a diagnostic sheet, having a substrate, and a layer of material disposed on a first surface of the substrate, where the layer of material changes color after contacting the precoat solution, and an image scanner configured to capture a pattern on a surface of the diagnostic sheet after the precoat solution is deposited. The layer of material of the diagnostic sheet may include a moisture sensitive composition or a pH indicator. A method includes providing a diagnostic sheet to an inkjet printing system, where the diagnostic sheet may include a layer of material that changes color after contacting a precoat solution, and when needed, correcting one or more jetting operations.