UV Irradiator Segmentation for Inkjet Head Clogging Prevention
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Solution Overview
Problem
Inkjet printers with ultraviolet-curable inkjet heads face clogging issues due to stray light generated when the head gap and surface roughness of the recording medium increase, leading to inefficient ink curing.
Innovation Solution
The inkjet printer incorporates a controller that adjusts the ultraviolet irradiator's illumination modes, including inner and outer regions, to minimize stray light exposure on the inkjet head by selectively turning off or reducing the inner illumination region when stray light is detected, and switching to higher intensity modes for faster curing when clogging is not an issue, based on head gap, surface reflectance, and scanning speed thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head gap is increased to accommodate greater surface roughness of the recording medium, then the inkjet head is less prone to contact with the recording medium, but stray light increases causing the inkjet head to be irradiated with ultraviolet rays and become clogged with ink
Solution Approach 1:
The ultraviolet irradiator is divided into multiple independent illumination regions (first, second, third, and fourth regions) that can be controlled separately. This segmentation allows selective illumination of different areas, enabling the system to reduce or turn off illumination in regions that would create stray light toward the inkjet head while maintaining illumination in regions needed for ink curing, thereby resolving the contradiction between preventing head clogging and ensuring effective ink curing.
Solution Approach 2:
Different illumination regions are assigned different illumination states (lit or unlit) based on their spatial relationship with the inkjet head and recording medium. The inner regions (first and second) that are more likely to generate stray light toward the head are controlled differently from the outer regions (third and fourth), allowing localized quality control of ultraviolet irradiation to simultaneously prevent head clogging and ensure effective ink curing.
2Reliability
If the inner illumination region is turned off to reduce stray light, then inkjet head clogging is reduced, but ink curing efficiency decreases
Solution Approach 1:
The ultraviolet irradiator is divided into multiple independent illumination regions (first, second, third, and fourth regions) that can be controlled separately. This segmentation allows selective illumination of different areas, enabling the system to reduce or turn off illumination in regions that would create stray light toward the inkjet head while maintaining illumination in regions needed for ink curing, thereby resolving the contradiction between preventing head clogging and ensuring effective ink curing.
Solution Approach 2:
The controller dynamically changes the illumination parameters (on/off state) of different regions based on detected conditions such as head gap and recording medium properties. By adjusting which regions are illuminated and at what intensity, the system optimizes the balance between preventing head clogging and maintaining efficient ink curing speed.
3Reliability
If the head gap is increased to reduce contact with rough recording mediums, then mechanical contact issues are avoided, but ultraviolet ray reflection from the recording medium increases and irradiates the inkjet head
Solution Approach 1:
The harmful stray light path is effectively blocked by turning off the inner illumination regions (first and second regions) that are positioned to generate reflection toward the inkjet head. This extraction of the harmful illumination source prevents ultraviolet rays from being reflected off the recording medium and reaching the inkjet head, resolving the contradiction between maintaining head gap for contact prevention and reducing stray light intensity.
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
This configuration effectively reduces inkjet head clogging and enhances ink curing efficiency by dynamically managing stray light and radiation intensity, optimizing performance across varying printing conditions.
Implementation Method 1
an ultraviolet irradiator arranged to adjoin the inkjet head in a main scanning direction where the inkjet head relatively moves with respect to the recording medium, the ultraviolet irradiator configured to irradiate the ink with an ultraviolet ray
Data Source
AI summary
An inkjet printer includes: an inkjet head configured to eject an ink of an ultraviolet-curable type to a medium; an ultraviolet irradiator arranged to adjoin the inkjet head in a main scanning direction where the inkjet head relatively moves with respect to the medium, the ultraviolet irradiator configured to irradiate the ink with an ultraviolet ray; and a controller configured to control the ultraviolet irradiator. In the inkjet printer, the ultraviolet irradiator includes an inner illumination region arranged near the inkjet head in the main scanning direction, and an outer illumination region arranged opposite the inkjet head across the inner illumination region in the main scanning direction, and the controller includes a first irradiation mode where the inner illumination region is unlit and the outer illumination region is lit, and a second irradiation mode where the inner illumination region is lit and the outer illumination region is lit.