Inkjet Head Flushing Control for Uneven Humidity
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Solution Overview
Problem
Ink-jet printers face issues with clogging of ejection openings due to increased viscosity over time, leading to uneven humidity distribution during capping, resulting in unnecessary ink consumption during before-use flushing.
Innovation Solution
A liquid ejection apparatus with a capping unit, air supply and discharge openings, and a flushing control unit that divides ejection openings into groups based on their distance from these openings, allowing for varying ink discharge amounts to optimize flushing and reduce ink consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the same amount of ink is ejected from all ejection openings during before-use flushing, then the flushing process is simple, but ink consumption increases unnecessarily due to uneven humidity distribution
Solution Approach 1:
The patent applies local quality by differentiating the flushing amount based on the positional characteristics of each ejection opening group. Ejection opening groups are classified into three categories (first, second, and third groups) based on their distance from the humidifying mechanism, and different flushing amounts are assigned to each group to match their specific humidity conditions, thereby reducing unnecessary ink consumption while maintaining operational simplicity
Solution Approach 2:
The patent changes the parameter of flushing amount based on the positional parameter of ejection opening groups. By determining the group to which each ejection opening belongs and setting different flushing amounts for different groups, the system optimizes ink consumption according to the humidity distribution characteristics of each position
2Reliability
If humidification is performed in the ejection space, then clogging of ejection openings is suppressed, but humidity distribution becomes non-uniform causing varying drying degrees
Solution Approach 1:
The patent addresses the non-uniform humidity distribution by classifying ejection openings into different groups based on their positional characteristics and assigning different flushing amounts to each group. This local differentiation compensates for the varying humidity conditions at different positions while maintaining overall clogging suppression
3Loss of substance
If ejection openings are divided into groups based on distance from air supply and discharge openings, then ink consumption is reduced, but the flushing control system becomes more complex
Solution Approach 1:
The patent segments the ejection openings into three distinct groups (first, second, and third groups) based on their distance from the air supply and discharge openings. This segmentation allows for differentiated flushing control strategies for each group, reducing ink consumption while managing system complexity through clear categorization
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 ensures uniform ink distribution and reduces ink consumption by adjusting the amount of ink discharged from different ejection opening groups based on their humidity levels, preventing clogging and improving printing consistency.
Implementation Method 1
a humidification unit configured to perform a humidifying maintenance in the sealing state by supplying humid air into the ejection space via the air supply opening and by discharging air from the ejection space via the air discharge opening
Implementation Method 2
a head comprising an ejection face that comprises an ejection opening region having a plurality of ejection openings through which the head ejects liquid to record an image on a recording medium
Data Source
AI summary
A liquid ejection apparatus includes: a head including an ejection face inclining an ejection opening region having ejection openings; a capping unit for selectively establishing a sealing state or an open state; an air supply opening and an air discharge opening; a humidification unit for performing a humidifying maintenance; a recording control unit for performing image recording; and a flushing control unit for performing flushing. The flushing control unit controls the head to perform the flushing such that an amount of the liquid discharged from each of a discharge-side ejection-opening group and a supply-side ejection-opening group is greater than that of the liquid discharged from the other ejection-opening group.