Print Head Ejection-State Estimation for Kogation Recovery Timing
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Solution Overview
Problem
The continuous use of ink prone to scorching causes kogation on the heater, leading to a significant change in ejection characteristics, resulting in image impairment and a reduced lifetime of the printing head due to the limited number of kogation removal processes that can be performed.
Innovation Solution
A printing apparatus with a recovery processing unit that estimates the ejection state based on heater driving times to determine the necessity of a kogation removal process, preventing unnecessary execution and extending the lifetime of the printing head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the kogation removal process is performed frequently to maintain image quality, then image impairment is prevented, but the lifetime of the printing head is reduced
Solution Approach 1:
The system performs preliminary estimation of the ejection state using heater driving time information before executing the kogation removal process. By predicting when kogation will affect image quality based on accumulated heater usage, the system can schedule the removal process at the optimal moment, preventing image impairment while avoiding unnecessary early interventions that would reduce printing head lifetime.
Solution Approach 2:
The system implements a feedback mechanism where heater driving time information is continuously monitored and used to estimate the current ejection state. This feedback loop allows the control unit to dynamically determine when the kogation removal process should be executed, balancing image quality maintenance with printing head preservation through data-driven decision making.
2Ease of operation
If the kogation removal process is performed at any time on demand, then image impairment can be addressed immediately, but unnecessary processes reduce the printing head lifetime
Solution Approach 1:
The system provides self-service functionality by automatically estimating the ejection state and determining the appropriate timing for kogation removal without requiring user intervention. The control unit independently monitors heater driving time, predicts when kogation will affect image quality, and schedules the removal process autonomously, eliminating the need for users to perform unnecessary maintenance operations.
3Productivity
If the upper protective layer is made thinner to enable more kogation removal processes, then the number of recovery operations increases, but the protection against ink scorching is reduced
Solution Approach 1:
Instead of making the protective layer thinner to enable more recovery operations, the system performs preliminary estimation of the ejection state to determine the optimal timing for kogation removal. This allows the upper protective layer to maintain its full thickness and protective function while still enabling multiple recovery operations by scheduling them at the precise moment when kogation becomes problematic, rather than prematurely.
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 solution effectively manages the kogation removal process to extend the printing head's lifetime by ensuring it is performed only when necessary, minimizing downtime and maintaining image quality.
Implementation Method 1
a method of generating heat by irradiating electromagnetic waves such as a laser to generate bubbles and using the pressure of the bubbles. There is also a method of generating bubbles by heating the ink using an electrothermal conversion element (hereinafter referred to as a 'heater') having a heating resistor.
Implementation Method 2
a method of pressurizing ink using an electromechanical conversion element such as a piezoelectric element
Implementation Method 3
This upper protective layer is formed of a material that contains a metal that dissolves due to the electrochemical reaction and does not form an oxide film that prevents the dissolution when heated. This allows the electrochemical reaction to occur and dissolve the surface layer of the upper protective layer.
Data Source
AI summary
It is an object of the present disclosure to realize a recovery process that prevents reduced lifetime of a printing head. One embodiment of the present invention is a printing apparatus including: a printing head having an ejection port for ejecting a liquid and a printing element for generating energy required to eject the liquid; a recovery processing unit for recovering the ejection state of the printing head; and a transition unit for causing a recovery process by the recovery processing unit to transition to an executable state, based on estimation information for estimating the ejection state.