Print Head Carriage Control for Ink Leakage Prevention
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Solution Overview
Problem
Inkjet printing apparatuses face issues with ink leakage from discharge ports due to dynamic pressure fluctuations caused by carriage movement, leading to reduced image quality, especially at high printing speeds where sufficient time is not available to reduce internal pressure from positive to negative before wiping operations.
Innovation Solution
A method is implemented to control the internal pressure of the print head by utilizing a sub-tank system with a water head difference method, where a wait time is introduced after carriage stoppage to allow internal pressure to drop from positive to negative before performing wiping operations, and adjusting carriage deceleration and printing strike density to optimize wait time and prevent ink leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the carriage moves at higher speed to improve throughput, then productivity is improved, but the acceleration/deceleration increases causing the internal pressure in the print head to fluctuate more widely, which may cause ink leakage
Solution Approach 1:
The patent introduces a wait time period after the carriage stops and before wiping is performed. This preliminary action allows the internal pressure in the print head to drop from positive to negative pressure, preventing ink leakage during subsequent wiping operations. The wait time is calculated based on carriage acceleration, deceleration, and printing strike density to ensure pressure equalization.
Solution Approach 2:
The patent dynamically adjusts the wait time parameter based on carriage acceleration, deceleration, and printing strike density. By changing this temporal parameter, the system adapts to different printing conditions and carriage speeds, ensuring that wiping is always performed at the optimal moment when internal pressure is negative, thus preventing ink leakage regardless of productivity requirements.
2Loss of time
If wiping is performed immediately after the carriage stops, then loss of time is reduced, but ink leakage occurs due to positive internal pressure breaking the meniscus
Solution Approach 1:
The patent introduces a wait time period after the carriage stops and before wiping is performed. This preliminary action allows the internal pressure in the print head to drop from positive to negative pressure, preventing ink leakage during subsequent wiping operations. The wait time is calculated based on carriage acceleration, deceleration, and printing strike density to ensure pressure equalization.
Solution Approach 2:
The patent calculates the wait time based on feedback from carriage acceleration, deceleration, and printing strike density parameters. This feedback mechanism determines the optimal waiting period needed for pressure equalization, allowing the system to adaptively adjust the timing of wiping operations to prevent ink leakage while minimizing time loss.
3Ease of operation
If a larger capacity ink tank is mounted on the carriage to reduce replacement frequency, then ease of operation is improved, but the inertia of the carriage increases affecting printing precision
Solution Approach 1:
The patent divides the ink supply system into two separate components: a large-capacity stationary ink tank and a moving print head assembly. The ink tank remains fixed in the apparatus body while the print head is mounted on the carriage. This segmentation allows the ink tank to maintain large capacity for reduced replacement frequency, while the moving carriage maintains low inertia for high printing precision.
Solution Approach 2:
The patent introduces a supply tube as an intermediary component connecting the stationary ink tank to the moving print head. This intermediary allows ink to be supplied from the fixed tank to the moving print head without requiring the entire ink tank to move with the carriage, thus resolving the contradiction between tank capacity and carriage inertia.
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 approach effectively suppresses ink leakage and dripping from discharge ports, maintaining image quality even at high speeds by ensuring wiping operations are performed when the internal pressure is negative, thus preventing meniscus breakage and ink loss.
Implementation Method 1
A method is implemented to control the internal pressure of the print head by utilizing a sub-tank system with a water head difference method
Implementation Method 2
when the ink in the supply tube oscillates as the carriage moves, dynamic pressure is applied to the ink due to inertia
Implementation Method 3
dynamic pressure is applied to the ink due to inertia
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~3D
AI summary
A printing apparatus comprises a carriage (104) including a print head (101) that discharges ink, the carriage reciprocally moving relative to a print medium, wiping means (301) for wiping a discharge port surface, and control means for controlling a movement operation of the carriage and a wiping operation of the wiping means such that when a deceleration when stopping the carriage is a first deceleration, a time from when the carriage stops to when the wiping means starts wiping is set to a first time, and when the deceleration when stopping the carriage is a second deceleration lower than the first deceleration, the time from when the carriage stops to when the wiping means starts wiping is set to a second time shorter than the first time.