Recording Element Board Bubble Communication Timing
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Solution Overview
Problem
Existing liquid discharge heads, such as thermal inkjet systems, suffer from satellite droplet formation due to the separation of the droplet tail from the main droplet during flight, leading to image quality deterioration, as the timing of bubble communication with the atmosphere is often late, causing the rear portion of the droplet to separate from the main droplet.
Innovation Solution
A recording element board and liquid discharge head design that optimizes the configuration of the pressure chamber, discharge orifice, and channel layout to ensure earlier bubble communication with the atmosphere, reducing satellite formation by promoting a thinner liquid film between the droplet and ink within the channel, thereby minimizing the droplet tail and enhancing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the heating resistance element is made larger than the discharge orifice opening, then more liquid is included in the main droplet, but the timing of bubble communication with the atmosphere is delayed
Solution Approach 1:
The pressure chamber is divided into a first pressure chamber and a second pressure chamber separated by a partition. The first pressure chamber contains the heating resistance element and communicates with the atmosphere through a first communication hole, while the second pressure chamber supplies liquid through a second communication hole. This segmentation allows the bubble to communicate with the atmosphere earlier in the first chamber while maintaining adequate liquid volume in the second chamber.
Solution Approach 2:
A partition acts as an intermediary structure between the first and second pressure chambers. It separates the chambers while allowing controlled interaction through communication holes, enabling the bubble to escape through the first chamber without completely isolating the liquid supply in the second chamber.
2Quantity of substance
If bubble communication with atmosphere is delayed, then more liquid is discharged, but satellite droplets are generated due to droplet tail separation
Solution Approach 1:
By segmenting the pressure chamber into two separate chambers with different communication functions, the system enables early bubble release through the first chamber while maintaining liquid supply in the second chamber, thereby preventing satellite droplet formation without reducing discharge amount.
Solution Approach 2:
The first communication hole is positioned to allow the bubble to communicate with the atmosphere before the liquid is fully discharged from the second chamber. This preliminary action of bubble release prevents the droplet tail separation that causes satellites.
3Object-generated harmful factors
If the pressure chamber height is increased to include more liquid in the main droplet, then satellite formation is reduced, but the device complexity increases
Solution Approach 1:
Instead of increasing the overall pressure chamber height, the chamber is segmented into two smaller chambers arranged horizontally or vertically. This segmentation achieves the satellite reduction effect through proper bubble communication timing without requiring a single large-height chamber, thus controlling device complexity.
Solution Approach 2:
The solution transitions from increasing height in one dimension to using a partitioned configuration that可以利用 multiple spatial arrangements (horizontal or vertical separation), effectively solving the problem through dimensional flexibility rather than simply increasing size.
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 design effectively reduces satellite droplet formation, improving image quality by ensuring the bubble communicates with the atmosphere earlier, resulting in a shorter droplet tail and more precise ink deposition on the recording medium.
Implementation Method 1
the liquid is heated to cause film boiling, and force of bubbling is used
Implementation Method 2
A heating resistance element (heater) is formed within the pressure chamber of the recording element board, with liquid being discharged from the discharge orifice by discharge energy that the heating resistance element has generated
Implementation Method 3
make the bubble, generated by application of thermal energy from the heating resistance element to separate liquid within the pressure chamber from liquid in the channel, to communicate with the atmosphere at the time of discharging
Data Source
Figure 1
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Figure 3
AI summary
A recording element board (10) includes a discharge orifice (13) discharging liquid, a pressure chamber (23) communicating with the discharge orifice (13), a recording element (15) generating thermal energy to cause bubbling of liquid and disposed in the pressure chamber (23) facing the discharge orifice (13), and a substrate (11) where the recording element (15) is formed. When the recording element (15) is driven and liquid of within the pressure chamber (23) is discharged, a generated bubble (B) communicates with the atmosphere. A discharge orifice projection region (13P) where the discharge orifice (13) has been projected on the substrate (11) includes a region extending beyond a heat-generating region projection region (15P) where the heat-generating region of the recording element (15) has been projected on the substrate (11), or the outline of the discharge orifice projection region (13P) is circumscribed by the outline of the heat-generating region projection region (15P).