Ink Ejection Apparatus Intermittent Purge Control
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in properly purging ink from nozzles when ambient temperatures are lower than a predetermined level, leading to increased ink viscosity and resistance, which can result in incomplete ejection due to the need for high-pressure pumps or enlarged head sizes, or ineffective heating by heaters when the ink is cold.
Innovation Solution
A liquid ejection apparatus equipped with a temperature sensor, heater, and purge controller that adjusts the pressurization of the ink by a pressurizer to ensure proper purging, using continuous or intermittent high-pressure pulses based on ambient temperature, and heating the ink to maintain desired viscosity, thereby reducing resistance without increasing pump cost or head size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-pressure pump is used to increase pressure on cold ink, then purging effectiveness is improved, but device cost and head size are increased
Solution Approach 1:
The heater is activated before the pressurizer to preheat the ink in the liquid path. This preliminary heating action reduces the ink viscosity before pressurization, allowing the standard-pressure pump to effectively purge the nozzles without requiring a high-pressure pump, thus resolving the contradiction between purging effectiveness and device complexity.
Solution Approach 2:
The heater acts as an intermediary element between the cold ink and the pressurizer. By introducing thermal energy as an intermediate action, the system transforms the physical state of the ink (reducing viscosity) before mechanical pressurization, enabling effective purging with a standard pump rather than requiring a complex high-pressure pump system.
2Productivity
If the pressurizer is continuously driven to eject a predetermined amount of liquid, then purging speed is improved, but energy consumption is increased when ambient temperature is low
Solution Approach 1:
The pressurizer operates in periodic cycles: heating phase followed by pressurization phase, rather than continuous operation. The controller alternates between activating the heater and activating the pressurizer, creating a rhythmic sequence of thermal and mechanical actions that achieves effective purging while minimizing energy consumption by allowing the system to rest between cycles.
Solution Approach 2:
The heater is activated in advance before the pressurizer operates. This preliminary heating reduces ink viscosity beforehand, making the subsequent pressurization more efficient. As a result, the pressurizer can achieve effective purging with shorter, less frequent operation cycles, reducing overall energy consumption while maintaining high purging productivity.
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
Enables effective purging at lower ambient temperatures without the need for expensive high-pressure pumps or enlarged head sizes, ensuring efficient ink flow and preventing clogging, while optimizing energy use by adjusting heating based on ambient conditions.
Implementation Method 1
a heater which heats liquid in at least a part of the liquid path
Implementation Method 2
a pressurizer which pressurizes liquid in the liquid path of the head
Data Source
AI summary
A liquid ejection apparatus includes a heater controller and a purge controller. The heater controller controls a heater to heat liquid in at least a part of a liquid path of a head when an ambient temperature of the head is lower than a first predetermined temperature. The purge controller controls a pressurizer so that: the pressurizer is continuously driven until a predetermined amount of liquid is ejected from ejection openings, when the ambient temperature is not lower than the first predetermined temperature; and the pressurizer is intermittently driven plural times until the predetermined amount of liquid is ejected from the ejection openings, when the ambient temperature is lower than the first predetermined temperature, an amount of liquid ejected from the ejection openings in response to a single driving action of the pressurizer being not larger than an amount of liquid heated by the heater.