Ink Circuit Boost Mechanism for Print Head Starvation
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Solution Overview
Problem
Ink jet print heads experience ink starvation during high levels of ink demand, leading to missing or undercolored areas in printed images due to insufficient ink reaching the jetting nozzles.
Innovation Solution
An ink circuit with a print head ink supply boost mechanism, which includes a reversible pump or a valve system that allows ink to flow into the print head through the outlet port during high demand, and a tank system with pressure sensors to control pump speeds and maintain optimal pressures, ensuring consistent ink flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single ink inlet port is used for normal printing, then the device complexity is low, but ink starvation occurs at high printing speeds
Solution Approach 1:
The single ink inlet port is segmented into two separate inlet ports (first ink inlet port and second ink inlet port), allowing independent ink supply paths. This enables the system to handle high ink demand at high printing speeds by opening both ports simultaneously, while maintaining simple operation during normal printing by using only one port.
Solution Approach 2:
The ink supply system dynamically adjusts the number of active inlet ports based on printing demand. During normal printing, only the first inlet port is active. During high-speed printing with high ink demand, the system activates the second inlet port to provide additional ink flow, ensuring reliable ink supply without increasing complexity during low-demand operations.
2Reliability
If a second ink inlet port is added for high demand printing, then ink supply stability improves, but device complexity increases
Solution Approach 1:
The second ink inlet port is designed with multi-functionality. It serves as a primary inlet during high-speed printing operations, and can alternatively function as an overflow path during normal printing when the first inlet port experiences pressure buildup. This universal design allows the same component to address both high-demand and normal printing scenarios without requiring entirely separate systems.
Solution Approach 2:
The overflow channel is pre-configured to connect the first ink inlet port chamber to the second ink inlet port chamber. This preliminary structural arrangement ensures that when ink pressure builds up in the first chamber during normal printing, the overflow path is already in place to redirect excess ink, preventing pressure-related printing defects without requiring active control mechanisms.
3Stability of the object's composition
If ink circulates through the print head during normal operation, then pigment sedimentation is prevented, but ink consumption increases
Solution Approach 1:
The ink circulation system maintains continuous ink flow through the print head during normal printing operations. The circulating pump ensures that ink constantly moves through the ink channels and jetting nozzles, preventing pigment particles from settling even during extended printing sessions. This continuous circulation preserves ink composition stability and prevents printing defects caused by sedimentation.
Solution Approach 2:
The ink circulation system is designed to be self-regulating. The pump automatically maintains ink flow based on system pressure conditions, and the overflow mechanism naturally redirects excess ink back to the reservoir without requiring external intervention. This self-service design minimizes unnecessary ink consumption while maintaining the circulation needed to prevent sedimentation.
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 solution effectively reduces the risk of ink starvation by ensuring a stable ink supply to the print head, even at high printing speeds, and prevents sedimentation of pigments by maintaining circulation and pressure control within the ink circuit.
Implementation Method 1
the pump causes ink to flow from the ink feed into the print head through the ink inlet port
Implementation Method 2
The further pump may, for example, be a reversible pump operable in one direction when printing at normal levels of ink demand to cause ink to flow out of the print head through the ink outlet port to the ink return, and operable in the opposite direction when printing at high levels of ink demand
Data Source
AI summary
An ink jet printer ink circuit (10) has an ink feed (18), an ink return (20), a pump (22) and a print head (24), the print head having ink inlet (26) and outlet (28) ports and ink jetting nozzles (30). When printing at normal levels of ink demand, the pump (22) causes ink to flow from the ink feed (18) into the print head (24) through the ink inlet port (26), and out of the print head (24) through the ink outlet port (28) to the ink return (20). The ink circuit (10) has print head ink supply boost means (22. 23) operable, when printing at high levels of ink demand, to cause ink to flow into the print head (24) through the ink outlet port (28) at the same time as ink flows into the print head (24) through the ink inlet port (26). Also a printer including such an ink circuit and a method of boosting a print head ink supply in such an ink circuit.