Liquid Ejecting Apparatus Nozzle Bubble Mixing Prevention
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Solution Overview
Problem
In ink jet printers, the mixing of bubbles into nozzles during the wiping process after cleaning can lead to deteriorated ink ejecting properties, as the pressure of ink in nozzles is maintained at negative pressure to prevent ink flow, potentially causing erroneous wiping and bubble introduction.
Innovation Solution
A liquid ejecting apparatus that creates a pressure difference between internal and external pressures in nozzles, allowing for controlled discharging and leaking processes to prevent bubble mixing, with a wiping process performed while maintaining higher internal pressure than external pressure to prevent bubble introduction, and using a cap to form a closed space for targeted discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pressure of ink in nozzles is maintained at negative pressure to prevent ink flow, then ink leakage is prevented, but bubbles can be pressed into the nozzles during wiping causing erroneous wiping and deteriorated ejecting properties
Solution Approach 1:
The patent dynamically changes the pressure state of the nozzle from negative pressure during normal operation to positive pressure during wiping. The pressure difference causing unit adjusts the internal pressure to be higher than external pressure specifically during the wiping process, transforming the static negative pressure system into a dynamic one that adapts to operational requirements.
Solution Approach 2:
The patent applies preliminary action by creating positive pressure in the nozzle before the wiping process begins. This preliminary pressure adjustment ensures that when the wiper contacts the nozzle, bubbles cannot be pressed inward, preventing erroneous wiping before it can occur.
2Reliability
If cleaning is executed on all nozzle groups, then ejecting properties are maintained, but liquid consumption increases unnecessarily
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different nozzle groups. Instead of uniform cleaning across all nozzles, the system identifies and applies cleaning only to specific nozzle groups that require it, based on their individual ejecting properties. This localized approach maintains reliability while reducing unnecessary liquid consumption.
Solution Approach 2:
The patent uses partial action by performing cleaning on only a portion of the nozzle groups rather than all nozzles. The control unit determines which specific nozzle groups require cleaning based on their ejecting properties, applying the cleaning function partially to achieve the necessary maintenance effect while minimizing liquid usage.
3Object-affected harmful factors
If wiping is performed from a cleaned nozzle group side toward an uncleaned nozzle group side, then dried nozzle forming face wiping is avoided, but bubble mixing in nozzles occurs
Solution Approach 1:
The patent fundamentally changes the pressure parameter from negative to positive during the wiping process. This parameter change reverses the pressure gradient that normally causes bubbles to be pressed into nozzles, ensuring that even when wiping direction is fixed, bubbles cannot enter the nozzle interior regardless of the pressure differential.
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 configuration effectively suppresses bubble mixing in nozzles during wiping, maintains ink quality, and reduces unnecessary liquid consumption by selectively targeting nozzle groups with ejecting failures, while allowing for efficient liquid discharge and reduced scattering.
Implementation Method 1
a pressure difference causing unit which causes a pressure difference so that the internal pressure is higher than the external pressure in nozzles included in one or more nozzle groups among the plurality of nozzle groups
Data Source
AI summary
A liquid ejecting apparatus performs a wiping process for wiping a nozzle forming face while a leaking process for leaking liquid from a plurality of nozzle groups is performed by setting a pressure difference to a second pressure difference which is smaller than a first pressure difference, after performing a discharging process for discharging liquid from a part of nozzle groups among the plurality of nozzle groups by setting the pressure difference to the first pressure difference, when a difference which is obtained by subtracting an external pressure which is a pressure in a space to which a nozzle is open from an internal pressure which is a pressure of liquid in the nozzle included in the plurality of nozzle groups which eject liquid is set to the pressure difference.