Inkjet Printer Piezo Actuator Drive Pulse Timing
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Solution Overview
Problem
The inkjet printer's ink droplet ejection characteristics vary when the propagate time period is altered, leading to decreased printing quality when multiple ink droplets are ejected from a single nozzle to form a pixel.
Innovation Solution
The inkjet printer employs a specific configuration of piezoelectric actuators and drive voltage pulse signals, where the time periods for drive voltage pulse signals are set to satisfy 4.5AL ≤ A + B + C ≤ 5.4AL, 2.60AL ≤ B ≤ 3.35AL, and 0.81AL ≤ C ≤ 1.14AL, ensuring consistent ink droplet ejection characteristics across multiple nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ink droplets are successively ejected from one nozzle to form one pixel, then the printing productivity is improved, but the ink droplet ejection characteristics vary when the propagate time period is altered, leading to decreased printing quality
Solution Approach 1:
The patent applies dynamics by making the drive pulse signal timing adaptable to variations in the propagate time period AL. The control unit dynamically adjusts the timing of drive pulse signals based on the actual propagate time period, which compensates for variations caused by manufacturing tolerances in ink channel dimensions. This dynamic adjustment maintains consistent ink droplet ejection characteristics across all nozzles while enabling multi-drop ejection for improved productivity.
Solution Approach 2:
The patent changes the timing parameters of drive pulse signals to compensate for variations in the propagate time period. By adjusting the timing of drive pulse signals applied to piezoelectric actuators, the system maintains uniform ink droplet ejection characteristics even when the propagate time period AL varies due to manufacturing tolerances. This parameter adjustment ensures that multiple ink droplets are ejected with consistent characteristics, resolving the contradiction between improved productivity and maintained printing quality.
2Ease of manufacture
If the propagate time period AL is varied for ink channels of an inkjet head, then the manufacturing ease is improved, but the ink droplet ejection characteristics are varied for plural nozzles, leading to decreased printing quality
Solution Approach 1:
The patent implements feedback by measuring the actual propagate time period AL for each ink channel and using this information to adjust the timing of drive pulse signals. The control unit receives feedback about variations in AL and compensates for these variations by dynamically adjusting the drive pulse timing, ensuring that ink droplet ejection characteristics remain consistent across all nozzles despite manufacturing tolerances in ink channel dimensions.
Solution Approach 2:
The patent changes the timing parameters of drive pulse signals based on the measured propagate time period AL. By adjusting the timing of drive pulse signals applied to piezoelectric actuators, the system compensates for variations in AL caused by manufacturing tolerances. This parameter adjustment ensures uniform ink droplet ejection characteristics across all nozzles, resolving the contradiction between ease of manufacture and consistency of ejection characteristics.
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 maintains consistent ink droplet ejection characteristics, reducing dispersion and enhancing printing quality even when multiple droplets are ejected from a single nozzle, ensuring precise and uniform ink placement on the recording medium.
Implementation Method 1
Each inkjet head includes a piezoelectric actuator which changes a volume of a corresponding ink chamber in response to a drive voltage pulse signal
Implementation Method 2
the propagate time period AL represents a time required for a pressure wave generated in the ink filling the ink channel to the other end of the ink channel
Data Source
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AI summary
An aspect of the invention provides an inkjet printer including: an inkjet head and a controller. The inkjet head moves relative to a recording medium to perform printing. The inkjet head includes, a flow path unit (4) including plural pressure chambers (10) respectively communicating with plural ink ejection ports (8) that ejects ink droplets toward the recording medium, and a piezoelectric actuator (21) configured to take a first state and a second state. The controller supplies a drive pulse signal to the piezoelectric actuator in order to repeat an operation in which the piezoelectric actuator transits from the first state to the second state and returns to the first state, for enabling the corresponding ink ejection port to eject a plurality of ink droplets. The controller supplies the drive pulse signal so that timings of the transition and the return satisfy some relationships.