Liquid Discharge Head Bubble Removal via Communicating Portion
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Solution Overview
Problem
Conventional inkjet recording heads face issues with bubbles remaining in liquid chambers, which can disrupt recording due to frequent suction recovery, and increasing liquid-chamber width or distance between ink supply ports is costly and undesirable.
Innovation Solution
The design includes an elongated liquid chamber with a communicating portion that is longer in the x-direction and wider in the y-direction than the liquid chamber, allowing bubbles to easily move from the liquid chamber to the introduction passage, reducing the influence of bubbles on recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid-chamber width is increased to prevent bubbles from staying in the liquid chambers, then bubble removal is improved, but the area of the recording element substrate increases, leading to higher cost
Solution Approach 1:
The invention introduces a communicating portion that extends in the x-direction (length direction) to create a three-dimensional bubble ejection path. Instead of simply widening the liquid chamber in the y-direction, the communicating portion provides an additional dimensional route for bubbles to travel from the liquid chamber to the ink introduction passage, effectively resolving the contradiction between bubble removal and substrate area.
2Reliability
If the distance between ink supply ports is increased to accommodate wider liquid chambers, then bubble movement is improved, but the recording element substrate area increases
Solution Approach 1:
The ink supply path is segmented into distinct functional regions: the liquid chamber for ink storage, the communicating portion for bubble ejection, and the ink introduction passage for ink supply. This segmentation allows each region to be optimized independently, with the communicating portion specifically designed to facilitate bubble removal without requiring increased distance between ink supply ports.
3Reliability
If frequent suction recovery is performed to remove bubbles from liquid chambers, then recording quality is maintained, but ink is wasted and productivity decreases
Solution Approach 1:
The liquid chamber structure with the communicating portion enables self-service bubble removal. Bubbles naturally move from the liquid chamber to the ink introduction passage through the communicating portion due to pressure differences and flow dynamics, eliminating the need for frequent external suction recovery operations and thereby improving productivity while maintaining recording quality.
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 enables stable recording by facilitating the movement of bubbles out of the liquid chamber, reducing the need for frequent suction recovery and maintaining recording quality without increasing the recording element substrate area.
Implementation Method 1
bubbles hardly move in the liquid chambers because the liquid-chamber width W is small. Thus, if bubbles remain or are left in the liquid chambers for a long time, they can exert a bad influence on recording.
Data Source
AI summary
A liquid discharge head includes a discharge port array having discharge ports for discharging liquid, a liquid chamber for supplying liquid to the discharge port array, and a liquid introduction passage for introducing liquid to the liquid chamber. A vertical cross section of the liquid chamber has an elongated shape. The liquid introduction passage is wider than the liquid chamber in a width direction of the elongated shape. A communicating portion is longer than a width of the liquid chamber and shorter than the liquid chamber, and is projecting from the liquid introduction passage for the liquid chamber. A bottom of the liquid introduction passage is disposed at a lower position than a top of the liquid chamber in the communicating portion, and a distance between the top and the bottom is longer than half of the width of the liquid chamber.