Liquid Ejecting Apparatus Ink Viscosity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in quickly suppressing the increase in viscosity of ink near the nozzle outlet, which can lead to ejection failures, as they rely on slow pressure changes to manage ink viscosity.
Innovation Solution
The apparatus employs a piezoelectric element to rapidly change the pressure in the pressure chamber, introducing air into the nozzle to stir the ink and prevent viscosity buildup, using distinct drive waveforms for liquid ejecting and air introduction modes to manage ink flow and viscosity effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure changes are transmitted to the ink by raising or lowering the pressure of the ink flowing through the ink circulation system, then the meniscus surface of the ink is reciprocated to suppress an increase in viscosity of the ink, but it is impossible to complete the operation for suppressing the increase in viscosity of the ink in a short time
Solution Approach 1:
The ink circulation system is divided into a circulation flow path and a spray flow path. The circulation flow path includes a pressure generating chamber for pressure changes, while the spray flow path includes a nozzle for direct ink ejection. This segmentation allows different functions to be performed in different paths, enabling rapid viscosity suppression through the spray path while maintaining circulation through the circulation path.
Solution Approach 2:
Air is introduced into the pressure generating chamber as an intermediary substance. The air bubbles mix with the ink and are carried through the nozzle, creating a spray effect that rapidly suppresses ink viscosity buildup near the nozzle outlet. The air acts as a mediator to achieve quick viscosity control without requiring slow pressure changes throughout the entire ink system.
2Reliability
If air is drawn into the pressure generating chamber through the nozzle, then the ink viscosity is suppressed, but the system requires distinct drive waveforms for liquid ejecting and air introduction modes
Solution Approach 1:
The system uses periodic drive waveforms with distinct patterns for liquid ejecting mode and air introduction mode. The control unit switches between these periodic waveforms based on operational requirements. The periodic nature of the waveforms allows for predictable and controllable ink ejection and air introduction cycles, maintaining reliability while managing control complexity through standardized periodic patterns.
Solution Approach 2:
The drive waveform is made dynamic and adjustable, with distinct patterns for different operational modes (liquid ejecting vs. air introduction). The control unit can switch between different waveform patterns depending on whether liquid ejection or air introduction is required, allowing the system to adapt its behavior to different operational needs while maintaining a unified hardware architecture.
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 approach allows for efficient suppression of ink viscosity near the nozzle, enabling rapid completion of the operation and preventing ejection failures by introducing air to maintain ink flow and reduce pressure changes gradually, thus ensuring stable ink ejection.
Implementation Method 1
A piezoelectric element is used to rapidly change the pressure in the pressure chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A liquid ejecting apparatus includes a nozzle for ejecting liquid, a pressure chamber communicating with the nozzle, a first individual flow path communicating with the pressure chamber, a second individual flow path communicating with the pressure chamber, a pressure generating unit changing a pressure of the liquid in the pressure chamber, and a control unit for driving the pressure generating unit. In the liquid ejecting apparatus, the liquid is supplied into the pressure chamber via one of the first individual flow path and the second individual flow path, and at least a part of the liquid supplied into the pressure chamber is discharged via the other. The control unit introduces air into the pressure chamber via the nozzle by driving the pressure generating unit, during a period in which the liquid is not ejected from the nozzle.