Dual Storage Liquid Ejecting Head Pressure Control
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Solution Overview
Problem
Liquid ejecting apparatuses, such as printers, face issues with liquid mixing in the recording head due to negative pressure after suction cleaning, leading to potential clogging and ink mixing with the head's internal components.
Innovation Solution
A liquid ejecting apparatus with a dual storage system and pressurization mechanism that maintains a water head difference to prevent liquid from being drawn into the head, using a first storage portion with a fluctuating liquid level below the nozzle surface and a second storage portion that communicates with it via a passage, along with a pressurizing portion and valves to control liquid flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If suction cleaning is performed to remove liquid from the nozzle, then cleaning effectiveness is improved, but negative pressure causes liquid to be drawn into the recording head causing mixing and potential clogging
Solution Approach 1:
The liquid storage system is divided into two separate portions: a first storage portion that maintains liquid supply and a second storage portion that receives excess liquid during pressurization. This segmentation prevents liquid from being drawn into the recording head while maintaining effective cleaning operations.
Solution Approach 2:
The system performs preliminary pressurization of the second storage portion before suction cleaning operations. By pre-establishing positive pressure in the second storage portion and having the first storage portion positioned at a higher elevation, the system creates a pressure barrier that prevents liquid from being drawn into the recording head during subsequent cleaning operations.
2Productivity
If liquid is supplied continuously to the recording head, then printing operation is maintained, but liquid may be drawn into the head during pressure changes causing mixing
Solution Approach 1:
The first storage portion acts as an intermediary between the liquid source and the recording head. It receives liquid from the liquid source, allows liquid level fluctuation, and supplies liquid to the second storage portion, thereby mediating pressure changes and preventing direct liquid drawing into the recording head during pressure variations.
Solution Approach 2:
The system utilizes hydraulic principles by positioning the first storage portion at a higher location than the nozzle surface, creating a water head difference that generates positive pressure in the liquid supply path. This hydraulic pressure barrier prevents liquid from being drawn into the recording head during operation.
3Device complexity
If a single storage portion is used, then device complexity is reduced, but inability to maintain pressure control leads to liquid drawing into head
Solution Approach 1:
The first storage portion is designed to allow dynamic liquid level fluctuation within a range lower than the nozzle surface. This dynamic design enables the liquid level to adjust during pressurization and discharge operations while maintaining the pressure barrier that prevents liquid from being drawn into the recording head.
Solution Approach 2:
The system introduces a vertical dimension by positioning the first storage portion at a higher elevation than the nozzle surface. This height difference creates a water head that generates positive pressure, adding a gravitational dimension to pressure control that effectively prevents liquid from being drawn into the recording head.
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
Effectively prevents liquid from being drawn into the recording head, reducing the risk of clogging and ink mixing, while allowing for efficient liquid supply and discharge, enhancing the reliability and performance of the printing process.
Implementation Method 1
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a water head difference
Implementation Method 2
a pressurizing portion that pressurizes an inside of the second storage portion
Implementation Method 3
a first valve configured to close the communication passage at the time of pressurization by the pressurizing portion
Data Source
AI summary
A liquid ejecting apparatus includes: a liquid ejecting head configured to eject a liquid from a nozzle provided on a nozzle surface; a first storage portion that has an introduction portion into which the liquid accommodated in a liquid accommodating portion is introduced, the introduction portion being provided at an upper portion of the first storage portion; a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a water head difference; a supply flow path for supplying the liquid from the second storage portion to the liquid ejecting head; a pressurizing portion that pressurizes an inside of the second storage portion; and a first valve configured to close the communication passage at the time of pressurization by the pressurizing portion.