Printing Apparatus Lighting Unit Non-Uniform Illuminance
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Solution Overview
Problem
The existing printing apparatuses face issues with ink discharge inefficiency due to UV light reflection from the platen or recordable medium surface, which can cure ink inside the nozzles, preventing correct discharge, and attempts to mitigate this by reducing illuminance or increasing distance between the discharging head and lighting unit either compromise ink curing or increase the carriage volume.
Innovation Solution
A printing apparatus with a discharging head and a lighting unit where a portion of the light sources are arranged in a first dense area and another portion in a second coarser area, with the second area closer to the discharging head, reducing the direct distance from the head to the coarser area, ensuring ink curing while minimizing ink discharge issues without increasing the carriage volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the illuminance of the lighting unit is reduced to prevent reflected light from curing ink in the nozzles, then ink discharge correctness is improved, but ink curability deteriorates
Solution Approach 1:
The lighting unit employs non-uniform illuminance distribution where the first lighting area (closer to the discharging head) has higher illuminance density for effective ink curing, while the second lighting area (farther from the discharging head) has lower illuminance density to minimize reflected light effects. This local differentiation allows simultaneous optimization of both curing efficiency and discharge correctness.
2Reliability
If the distance between the discharging head and the lighting unit is increased to prevent reflected light from reaching the nozzle surface, then ink discharge correctness is improved, but the volume of the carriage increases
Solution Approach 1:
Instead of uniformly increasing the distance between the discharging head and lighting unit, the patent creates different distance characteristics in different lighting areas. The second lighting area is positioned farther from the discharging head to reduce reflected light effects, while the first lighting area maintains closer proximity for effective curing. This localized distance differentiation achieves the desired effect without uniformly expanding the carriage volume.
3Illumination intensity
If the quantity of light sources per unit area is increased to ensure ink curability, then ink curability is improved, but the volume of the carriage increases
Solution Approach 1:
The lighting unit implements non-uniform light source distribution where the first lighting area has higher light source density per unit area to provide sufficient illuminance for ink curing, while the second lighting area has lower light source density to reduce overall volume. This localized density differentiation allows the system to achieve adequate curability without uniformly increasing the carriage volume throughout the entire lighting unit.
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 prevents ink discharge deficiencies while maintaining ink curability, reducing the impact of reflected light on the nozzles and ensuring effective curing without enlarging the carriage dimensions.
Implementation Method 1
a lighting unit having a plurality of light sources, e.g., LEDs, which may emit ultraviolet (UV) light at UV-curable ink discharged from a discharging head on a printable medium
Implementation Method 2
By emitting the UV light at the ink droplets landed on the printable medium, the ink may be cured and fixed on the printable medium
Implementation Method 3
the UV light emitted from the lighting unit may occasionally reflect off a surface of a platen or a surface of the recordable medium, and a nozzle surface of the discharging head may be irradiated with the reflected light
Data Source
AI summary
A printing apparatus, including a discharging head, a relative movable assembly to move a printable medium and the discharging head relatively, and a lighting unit including a plurality of light sources to emit light for curing the ink, is provided. A part of the plurality of light sources is arranged in a first lighting area, and another part of the plurality of light sources is arranged in a second lighting area. A quantity of the light sources per unit area in the second lighting area is smaller than a quantity of the light sources per unit area in the first lighting area. A direct distance from the discharging head to the second lighting area in a direction parallel to the predetermined direction is shorter than a direct distance from the discharging head to the first lighting area.