Perpendicular Filter Bubble Control Unit for Inkjet Heads
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Solution Overview
Problem
In liquid ejecting heads, such as ink jet recording heads, bubbles often intrude into the ink channel during filling or cartridge replacement, leading to pressure loss and clogging issues due to the limited space for bubble accumulation, necessitating frequent cleaning operations.
Innovation Solution
A bubble control unit is introduced, featuring a liquid channel with a first and second chamber, and communicating paths that allow bubble accumulation and retention, enabling independent flow of liquid even if the first path is clogged, and a filter disposed downstream to prevent clogging, reducing the need for frequent cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter is disposed parallel to the nozzle surface to prevent bubble clogging, then bubble prevention is improved, but the space for bubble accumulation is limited due to head downsizing
Solution Approach 1:
The patent changes the orientation of the filter from parallel to the nozzle surface to substantially perpendicular to the nozzle surface. This dimensional reorientation allows the filter to extend in the vertical direction, significantly increasing the space available for bubble accumulation above the filter while maintaining the same horizontal footprint. This resolves the contradiction by providing adequate bubble accumulation space without increasing the horizontal dimensions of the head.
Solution Approach 2:
The patent segments the liquid channel into distinct regions: a first liquid channel portion with the filter, a second liquid channel portion above the filter for bubble accumulation, and a third liquid channel portion for liquid ejection. This segmentation allows bubbles to be confined to the second portion, preventing them from reaching the nozzle while maintaining efficient liquid flow through the third portion.
2Reliability
If the filter area is enlarged to improve bubble capture, then bubble prevention is improved, but the head size increases
Solution Approach 1:
The filter is oriented substantially perpendicular to the nozzle surface, extending vertically rather than horizontally. This allows the filter to have a large effective area for bubble capture while occupying minimal horizontal space. The filter area is maximized in the vertical dimension without increasing the horizontal footprint of the head.
3Reliability
If frequent cleaning operations are performed to remove bubbles, then bubble accumulation is prevented, but liquid consumption increases
Solution Approach 1:
The patent designs a self-service bubble management system where bubbles automatically accumulate in the second liquid channel portion above the filter and are prevented from entering the ejection channel. The vertical orientation of the filter and the buoyancy of bubbles work together to create a self-regulating system that continuously manages bubbles without requiring external cleaning operations, thereby preventing liquid consumption.
4Device complexity
If the filter is disposed parallel to the nozzle surface, then the structure is simple, but cleaning operations must be performed frequently
Solution Approach 1:
The filter is reoriented from parallel to substantially perpendicular relative to the nozzle surface. This simple orientational change fundamentally improves bubble management by allowing bubbles to accumulate above the filter in the vertical direction, preventing them from reaching the nozzle and eliminating the need for frequent cleaning operations.
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 effectively suppresses liquid consumption by minimizing cleaning operations and prevents poor discharge issues like dead pixels by efficiently managing bubbles within the liquid channel.
Implementation Method 1
a bubble chamber extending upward from the first chamber
Implementation Method 2
a filter disposed downstream to prevent clogging
Data Source
AI summary
Provided is a bubble control unit for a liquid ejecting head which ejects liquid from a nozzle formed on a nozzle surface. The bubble control unit includes a liquid channel through which the liquid is supplied to the nozzle. In the bubble control unit, the liquid channel includes: a first chamber; a second chamber disposed on the upstream side from the first chamber; a first communicating path which has a bubble chamber extending upward from the first chamber, and makes the liquid within the second chamber to flow into the first chamber from a first communicating path inlet of the second chamber; and a second communicating path which is provided with a second communicating path inlet below the first communicating path inlet, separately from the first communicating path inlet, and makes the liquid within the second chamber to flow into the first chamber from the second communicating path inlet.