UV-Curable Gel Ink Spread Control via Substrate Temperature
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Solution Overview
Problem
Conventional printing processes using UV-curable gel inks often result in image defects such as pin-hole defects and corduroy-like lines due to the inherent properties of UV-curable gel ink, which are not effectively mitigated by pre-heating the substrate or reflowing the image, and these methods can introduce additional defects.
Innovation Solution
A method and apparatus that control the temperature of the substrate in a printing zone to optimize the spread of UV-curable gel ink, determining the spot size of ink spots and adjusting the temperature based on this measurement to achieve a target spot size, thereby minimizing image defects like pin-holes and corduroy effects, regardless of the substrate type or coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UV-curable gel ink is jetted onto a moving substrate, then printing productivity is improved, but line defects resembling corduroy or vinyl record appearance occur
Solution Approach 1:
The patent changes the temperature parameter of the substrate to control ink spread. By maintaining the substrate at a controlled temperature (e.g., room temperature or slightly elevated) during printing, the ink spread is optimized to prevent line defects while maintaining high-speed printing capability. This parameter change resolves the contradiction by enabling both productivity and image quality.
2Manufacturing precision
If the substrate is pre-heated or the image is reflowed to mitigate line defects, then image quality is improved, but pin-hole defects are introduced
Solution Approach 1:
The patent applies preliminary action by controlling the substrate temperature before and during the printing process. Instead of heating after printing (reflow), the substrate temperature is optimized in advance to prevent both line defects and pin-hole defects. This preliminary temperature control eliminates the need for subsequent heating steps that cause pin-hole defects.
3Manufacturing precision
If the ink spot size is reduced to improve image quality, then manufacturing precision is improved, but ink spread control becomes more difficult
Solution Approach 1:
The patent implements feedback control by measuring the actual ink spot size and adjusting the substrate temperature accordingly. The system monitors the ink spread and modifies the temperature parameter to achieve the desired spot size. This feedback mechanism enables precise spot size control while managing the complexity of temperature control through automated adjustment.
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 system effectively reduces image defects by optimizing ink spread, achieving a desired print quality by adjusting the substrate temperature to match the target spot size, thus minimizing pin-hole and corduroy defects across various substrates and coatings.
Implementation Method 1
causing, at least in part, the one or more ultraviolet-curable gel inks to be exposed to an ultraviolet light to cure the one or more ultraviolet-curable gel inks
Implementation Method 2
determining a temperature of at least the first substrate image area in the printing zone... causing, at least in part, a temperature of at least a second substrate image area in the printing zone to be based, at least in part, on the determined first spot size
Data Source
AI summary
An approach is provided for controlling ultraviolet-curable gel ink spread of a printed image. The approach involves causing, at least in part, one or more inks to be applied to a first substrate image area by one or more inkjets in a printing zone of a printer, the one or more inkjets being configured to form one or more first ink spots on the first substrate image area. The approach also involves determining a temperature of at least the first substrate image area in the printing zone. The approach further involves determining a first spot size of at least one of the one or more first ink spots. The approach additionally involves causing, at least in part, a temperature of at least a second substrate image area in the printing zone to be based, at least in part, on the determined first spot size.