Inkjet Head UV Irradiation Control for Nozzle Clogging
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Solution Overview
Problem
Inkjet printers using ultraviolet-curable ink face issues with nozzle clogging due to stray ultraviolet light reflecting from the print medium and reduced cumulative illuminance leading to inadequate ink curing, as seen in existing technologies.
Innovation Solution
An inkjet printer system with a controller that adjusts the peak illuminance of the ultraviolet irradiator based on carriage movement speed, maintaining constant cumulative light quantity by varying the irradiation time, and strategically positioning ultraviolet irradiation portions to minimize stray light reaching the nozzles, including the use of multiple ink types and nozzle arrangements to prevent clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ultraviolet irradiator irradiates the ink at high peak illuminance, then the ink curing efficiency is improved, but the amount of stray light reaching the nozzles increases causing clogging
Solution Approach 1:
The patent applies dynamics by making the peak illuminance of the ultraviolet irradiator variable rather than fixed. The controller dynamically adjusts the peak illuminance based on the carriage moving speed: when the carriage moves at the second (slower) speed, the peak illuminance is set lower to reduce stray light; when the carriage moves at the first (faster) speed, the peak illuminance is set higher to maintain curing efficiency. This dynamic adjustment resolves the contradiction between curing quality and nozzle clogging prevention.
Solution Approach 2:
The patent changes the parameter of peak illuminance according to operating conditions (carriage speed). By establishing a relationship where peak illuminance varies with carriage moving speed, the system optimizes both ink curing quality and stray light control. The cumulative light quantity is maintained constant through this parameter change, ensuring proper curing while reducing stray light effects at slower speeds.
2Manufacturing precision
If the carriage moves at the second (slower) speed to improve printing quality, then the ink curing becomes more thorough, but the irradiation time increases causing more stray light and nozzle clogging
Solution Approach 1:
The patent changes the peak illuminance parameter based on carriage speed to resolve this contradiction. When the carriage moves at the second (slower) speed, the peak illuminance is reduced proportionally, which compensates for the longer irradiation time. This ensures that the cumulative light quantity remains constant, providing thorough curing without excessive stray light accumulation that would cause nozzle clogging.
Solution Approach 2:
The system implements feedback control where the controller monitors the carriage moving speed and automatically adjusts the peak illuminance of the ultraviolet irradiator accordingly. This closed-loop control ensures that the cumulative light quantity remains constant regardless of carriage speed, preventing both insufficient curing and excessive stray light generation.
3Quantity of substance
If the ultraviolet irradiator is positioned close to the inkjet head to improve irradiation efficiency, then the cumulative light quantity increases, but the stray light more easily reaches the nozzles causing clogging
Solution Approach 1:
The patent applies local quality by differentiating the ultraviolet irradiation into two distinct portions: a head position ultraviolet irradiation portion closer to the inkjet head that provides necessary cumulative light quantity, and a tail position ultraviolet irradiation portion farther from the nozzles. The controller can selectively control these portions, allowing the head position portion to provide sufficient irradiation while the tail position portion helps reduce stray light reaching the nozzles.
Solution Approach 2:
The ultraviolet irradiator is segmented into multiple independent ultraviolet emission portions (head position and tail position portions) that can be controlled separately. This segmentation allows differential control where the head position portion operates at higher intensity for adequate curing, while the tail position portion operates at lower intensity or is selectively deactivated to minimize stray light generation that would reach the nozzles.
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 suppresses nozzle clogging and ensures appropriate printing by optimizing ultraviolet light distribution and duration, maintaining consistent ink curing quality across varying print conditions.
Implementation Method 1
an ultraviolet irradiator configured to irradiate the ink ejected from the inkjet head with an ultraviolet to cure the ink
Implementation Method 2
the ultraviolet reflected by the surface of a print medium or the like becomes stray light
Data Source
AI summary
An inkjet printer includes an inkjet head having multiple nozzles that eject an ultraviolet-curable ink, an ultraviolet irradiator that cures the ink, a carriage on which the inkjet head and the ultraviolet irradiator are mounted, a carriage drive mechanism that moves the carriage in a main scanning direction, and a controller that controls the ultraviolet irradiator. A part of the ultraviolet irradiator disposed at the same position as the inkjet head in a sub scanning direction is a head position ultraviolet irradiation portion. The controller makes a peak illuminance of ultraviolet with which the head position ultraviolet irradiation portion irradiates the ink when the carriage moves at a moving speed V2 lower than a peak illuminance of ultraviolet with which the head position ultraviolet irradiation portion irradiates the ink when the carriage moves at a moving speed V1, where the moving speed V2 is lower than the moving speed V1.