Ink-jet Head Drive Pulse Control for Droplet Impact Accuracy
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Solution Overview
Problem
The existing methods for driving ink-jet heads result in a discharge speed difference among ink droplets of varying volumes, leading to inconsistent impact positions and deteriorated image quality during printing.
Innovation Solution
The method involves varying the duration of initial and final drive pulses and adjusting the rest time to maintain a constant total time, with the initial drive pulse duration set between 1/1.5 to 1.8 times that of the final drive pulse, to ensure consistent discharge speed across different ink volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the same drive pulse duration is used for all ink droplet volumes, then the discharge speed varies among different ink volumes, but if the drive pulse duration is varied, then the discharge speed becomes consistent across different ink volumes
Solution Approach 1:
The drive pulse duration is made dynamic rather than fixed, allowing it to vary based on the number of droplets to be discharged. The control unit adjusts the pulse width according to the ink volume requirements, enabling consistent discharge speed across different droplet volumes while maintaining operational flexibility.
Solution Approach 2:
The patent changes the temporal parameter (pulse duration) of the drive signal to optimize discharge performance. By varying the pulse width parameter in response to different ink volume requirements, the system achieves uniform discharge speed without requiring structural modifications to the inkjet head.
2Quantity of substance
If multiple drive pulses are applied to discharge larger ink volumes, then the discharge volume increases, but the discharge speed becomes inconsistent compared to single droplet discharge
Solution Approach 1:
The system employs periodic drive pulses with specifically controlled intervals and durations. By applying multiple pulses in a regulated sequence with appropriate rest periods between them, the ink is discharged in controlled increments while maintaining consistent speed characteristics similar to single-droplet discharge.
Solution Approach 2:
The control unit prepares the discharge sequence in advance by determining the optimal pulse duration and interval based on the required ink volume. This preliminary planning ensures that each subsequent pulse contributes to the total discharge volume while maintaining speed consistency from the first to the last droplet.
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 eliminates the discharge speed difference among ink droplets of different volumes, improving impact position accuracy and resulting in enhanced image quality during printing.
Implementation Method 1
a plurality of grooves 5 which communicate with nozzle holes 11; an ink flow path 21 for supplying ink to each of the plurality of grooves 5; a piezoelectric actuator 1 for varying a volume of the plurality of grooves 5; a discharge control unit 111 which applies a drive pulse to the piezoelectric actuator 1
Implementation Method 2
In a piezoelectric ceramic plate 1, a plurality of grooves 5 are arranged in parallel with each other... When an electric field is applied to the electrode 4 and the electrode 9 which sandwich the side wall 7, each of the side walls 7 deforms in a desired direction
Data Source
AI summary
Provided is an ink-jet head and an ink-jet type recording apparatus for improving an impact position accuracy of ink droplets by eliminating a discharge speed difference of ink droplets when an ink volume is changed gradually in a plurality of steps to perform gradation expression. Among discharge pulse signals to be applied a plurality of times for gradually changing and discharging the ink droplet volume, a signal waveform of a final drive pulse and a signal waveform of an initial drive pulse to be operated at least once before the final drive pulse, are varied from each other so as to establish a predetermined relation therebetween.