Ink Jet Head Driving Method Using Boost Pulse for Ejection Speed Uniformity
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Solution Overview
Problem
Ink jet printers face instability and degraded print quality due to uneven ejection speeds of ink droplets, particularly with the first droplet being slower than subsequent droplets in multi-drop driving systems, leading to increased power consumption and potential displacement in ink deposition between gradations.
Innovation Solution
An ink jet head driving method that applies a boost pulse prior to the first ink droplet when the number of droplets is small and disables the boost pulse when the number is large, controlling the pressure vibration to achieve uniform ejection speed and quantity, thereby improving print quality and enabling high-speed printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a boost pulse is applied to increase the ejection speed of the first droplet, then the ejection speed uniformity is improved, but the power consumption increases
Solution Approach 1:
A boost pulse is applied before the first drive pulse to preliminarily vibrate the ink meniscus and prepare the pressure chamber for droplet ejection. This preliminary action ensures that the first droplet is ejected at the same speed as subsequent droplets, achieving uniform ejection speed without requiring excessive energy during the main ejection phase.
Solution Approach 2:
The driving method uses periodic pulses (boost pulse followed by drive pulses) to eject multiple droplets in sequence. By applying the boost pulse only when the number of droplets is small (1-3 droplets), the system achieves periodic optimization of ejection uniformity while minimizing overall power consumption through selective application.
2Manufacturing precision
If the number of droplets is increased to achieve gradation printing, then the print quality is improved, but the ejection speed uniformity deteriorates due to residual pressure vibration
Solution Approach 1:
The boost pulse serves as a preliminary action that resets the pressure chamber state before each droplet ejection sequence. By applying this preliminary vibration, the system compensates for the effects of residual pressure from previous droplets, ensuring that each droplet (whether 1st, 2nd, or subsequent) is ejected at a consistent speed, thereby maintaining print quality in multi-drop gradation printing.
Solution Approach 2:
The system changes the driving parameters dynamically by applying a boost pulse with specific amplitude and duration before the main drive pulses. This parameter change allows the pressure chamber to reach an optimal state for consistent droplet ejection, maintaining uniform ejection speed across multiple droplets used for gradation printing.
3Stability of the object's composition
If the boost pulse is applied continuously for all droplet numbers, then the ejection speed uniformity is maintained, but the printing speed decreases
Solution Approach 1:
The system dynamically adjusts the driving method based on the number of droplets to be ejected. When the number of droplets is small (1-3), the boost pulse is applied to ensure uniform ejection speed. When the number of droplets is large (4 or more), the boost pulse is omitted to maintain high printing speed. This dynamic adaptation optimizes both ejection uniformity and printing efficiency.
Solution Approach 2:
The boost pulse application is localized to specific conditions (small number of droplets) rather than being applied universally. This localized approach ensures that ejection speed uniformity is maintained where it matters most (when few droplets are ejected), while avoiding unnecessary delays when many droplets are ejected, thus optimizing overall printing performance.
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 enhances the ejection speed of the first few droplets, stabilizes ink deposition, reduces power consumption, and maintains print quality by selectively using a boost pulse only when necessary, allowing for efficient high-speed printing.
Implementation Method 1
a piezoelectric actuator 14 provided in correspondence with each of the pressure generating chambers 17 to apply vibration to the pressure generating chambers 17 via a vibration plate 13
Implementation Method 2
applying a boost pulse prior to a first drive pulse to increase an ejection speed of ink drops
Implementation Method 3
changing the capacity of a pressure chamber in which ink has been filled by a piezoelectric element in response to a print signal, and then, ejecting an ink droplet from a nozzle which communicates with the pressure chamber by the resulting pressure change
Data Source
AI summary
In an ink jet head driving method for applying a drive pulse to an actuator ACT to change capacities of a plurality of pressure chambers in which ink has been filled, ejecting an ink droplet from a nozzle formed in communication with the pressure chamber to print onto a printing medium, and moreover, controlling the number of ink droplets ejected according to the number of drive pulses to carry out gradation printing, a control is made such that, in the case where the number of ink droplets is small, a boost pulse Pb for amplifying a pressure vibration of the pressure chamber is applied prior to a drive pulse for ejecting a first ink droplet, and in the case where the number of ink droplets is large, applying of the boost pulse Pb is disabled.