Liquid Ejection Head Humidification Control for Viscosity Management
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in managing viscosity increases in nozzles, leading to excessive liquid consumption during humidification and preliminary ejection, as they struggle to maintain ideal viscosity levels, especially when humidification liquid runs low.
Innovation Solution
A liquid ejection apparatus with a humid-air supply mechanism, a detection system for remaining humidification liquid, and a controller that adjusts the amount of humid air and image recording liquid discharge based on liquid levels, allowing for efficient humidification and reduced liquid consumption by optimizing humid air supply and discharge amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If humidification is performed to reduce liquid viscosity in nozzles, then the liquid viscosity is reduced and ejection performance is improved, but the consumption of humidification liquid increases
Solution Approach 1:
The patent applies dynamics by making the humidification process adjustable rather than fixed. The control unit dynamically adjusts the amount of humid air supplied based on detection signals from the liquid level detection unit, allowing the system to adapt humidification intensity to actual liquid levels, thereby reducing unnecessary humidification liquid consumption while maintaining effective viscosity control.
Solution Approach 2:
The patent implements feedback control through the liquid level detection unit that continuously monitors the liquid level in the humidification liquid supply chamber and sends detection signals to the control unit. This feedback mechanism allows the system to adjust humidification operations based on real-time liquid level information, preventing excessive humidification liquid usage while ensuring adequate viscosity management.
2Reliability
If preliminary ejection is performed to discharge thickened liquid from nozzles, then the nozzle viscosity is reduced, but a large amount of image recording liquid is consumed
Solution Approach 1:
The patent applies preliminary action by performing preliminary ejection operations before normal image recording to discharge thickened liquid from nozzles. The control unit determines when preliminary ejection is needed based on liquid level detection and executes it to restore proper liquid flowability, preventing viscosity-related ejection failures before they affect image quality.
Solution Approach 2:
The patent uses parameter changes by adjusting the amount of humid air supplied to the ejection space based on liquid level detection. When liquid levels are low, the system modifies humidification parameters to compensate for increased viscosity, reducing the need for extensive preliminary ejection and thereby conserving image recording liquid.
3Reliability
If the amount of humid air supplied is increased to better humidify the ejection space, then the liquid viscosity is more effectively reduced, but the humidification liquid consumption increases
Solution Approach 1:
The system dynamically adjusts the amount of humid air supplied based on real-time liquid level detection. When liquid levels are sufficient, normal humidification amounts are used for effective viscosity reduction. When liquid levels drop, the system reduces humidification intensity to conserve humidification liquid, preventing the contradiction between effectiveness and consumption.
Solution Approach 2:
The control unit changes humidification parameters (amount of humid air supplied) based on detection signals from the liquid level detection unit. This parameter adjustment allows the system to optimize the balance between viscosity reduction effectiveness and humidification liquid consumption, applying stronger humidification only when liquid levels support it.
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 solution reduces the consumption of humidification liquid, prolongs the period for discharging image recording liquid, and prevents viscosity increases in nozzles, ensuring efficient operation even when humidification liquid is low.
Implementation Method 1
an air in a cap that has sealed nozzles of a liquid-droplet ejection head is humidified using an air-conditioning device
Data Source
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AI summary
A liquid ejection apparatus including: a liquid-ejection head (10) having a plurality of ejection openings (14a) and configured to eject image recording liquid through the ejection openings to record an image on a recording medium; a sealing mechanism (40(41,42,43),8a) configured to selectively establish (i) a sealed state in which an ejection space (S1) in which the ejection openings are open is sealed from an outside and (ii) an unsealed state in which the ejection space is not sealed from the outside; a humid-air supply mechanism (50) including a humidification-liquid tank (54) storing humidification liquid and configured to supply an air humidified by the humidification liquid into the ejection space; a humidification-liquid detecting device (58) configured to detect a remaining amount of the humidification liquid stored in the humidification-liquid tank; a liquid-discharge portion (17) configured to have the image recording liquid be discharged from the plurality of the ejection openings; and a controller (1p) configured to control the sealing mechanism, the humid-air supply mechanism, and the liquid-discharge portion, wherein the controller controls the humid-air supply mechanism to supply the humid air into the ejection space during the sealed state of the ejection space established by the sealing mechanism and then controls the liquid-discharge portion such that the image recording liquid is discharged from the plurality of the ejection openings prior to the ejection of the image recording liquid onto the recording medium for recording the image on the recording medium, and wherein, where the remaining amount of the humidification liquid detected by the humidification-liquid detecting device is less than a first predetermined value, the controller is configured to execute a control such that an amount of the humid air supplied into the ejection space in the sealed state and an amount of the image recording liquid discharged from the plurality of the ejection openings are respectively made small and large as compared with in a case where the remaining amount of the humidification liquid detected by the humidification-liquid detecting device is equal to or larger than the first predetermined value.