Liquid Ejecting Head Cleaning via Selective Flow Intensification
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Solution Overview
Problem
Existing liquid ejecting apparatuses, such as ink jet printers, face challenges in achieving effective cleaning of nozzles due to reduced ink flow rate and pressure, especially with high viscosity inks like UV ink, leading to inefficient bubble removal and nozzle clogging.
Innovation Solution
A liquid ejecting apparatus with multiple liquid ejecting heads is equipped with a supply path, a circulation path, and opening and closing valves, allowing selective cleaning by intensifying the liquid flow to targeted heads through a liquid sending unit and depressurization unit, which increases the flow rate and pressure, enhancing cleaning efficacy while preventing nozzle leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink flow rate is increased to improve cleaning effect, then cleaning capability is improved, but pump capability requirements increase and system complexity increases
Solution Approach 1:
The invention divides the cleaning function into two independent units: a liquid sending unit for supplying ink and a depressurization unit for removing air bubbles. This segmentation allows each unit to be optimized independently, reducing the complexity requirements for any single pump while achieving effective cleaning through coordinated operation.
Solution Approach 2:
The invention dynamically adjusts the operation sequence between the liquid sending unit and depressurization unit. The liquid sending unit operates first to establish ink flow, then the depressurization unit activates to remove bubbles, creating a dynamic cleaning process that adapts to different cleaning needs without requiring constant high pump capability.
2Ease of operation
If ink circulation is used for nozzle cleaning, then cleaning is performed, but ink pressure cannot be sufficiently raised and cleaning efficacy is reduced
Solution Approach 1:
The liquid sending unit performs preliminary action by supplying ink to the liquid ejecting heads before the depressurization unit removes air bubbles. This preliminary ink supply establishes the necessary liquid environment and pressure conditions, enabling subsequent effective bubble removal without requiring excessively high circulation pressure.
3Reliability
If high viscosity ink is used, then ink quality is improved, but cleaning difficulty increases due to reduced flow and pressure
Solution Approach 1:
The invention uses the depressurization unit to create negative pressure conditions that facilitate the removal of air bubbles from high viscosity ink. By controlling pressure differentials rather than relying solely on high flow rates, the system effectively cleans nozzles even when using high viscosity inks that would otherwise be difficult to circulate and clean.
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 enables effective cleaning of nozzles by intensifying the liquid flow and pressure, improving bubble removal and preventing nozzle clogging, even with high viscosity inks, while maintaining stable ink pressure and flow rates across all heads.
Implementation Method 1
a liquid sending unit that applies a force sending the liquid from the tank toward the liquid ejecting heads
Implementation Method 2
depressurization unit, which increases the flow rate and pressure, enhancing cleaning efficacy while preventing nozzle leakage
Data Source
AI summary
A liquid ejecting apparatus provided with N (N≧2) liquid ejecting heads which eject liquid, the liquid ejecting apparatus including a supply path through which liquid is supplied from a tank to the N liquid ejecting heads, a circulation path through which liquid is returned from the liquid ejecting heads to the tank, N opening and closing valves that are installed for each liquid ejecting head on at least one of the supply path and the circulation path, and a liquid sending unit that applies a force sending the liquid from the tank toward the liquid ejecting heads. M opening and closing valves corresponding to M (M<N) liquid ejecting heads selected as cleaning targets are selected to be opened among the N opening and closing valves and the liquid sending unit is driven, to selectively send liquid to the M liquid ejecting heads of the cleaning targets among the N liquid ejecting heads, thereby performing cleaning.