Inkjet Head Units with Differential Drive Voltage for Reliability
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Solution Overview
Problem
Conventional inkjet printers experience reduced product life due to degradation of piezoelectric elements in head units used most frequently, particularly those printing at the center region of the recording medium, where higher drive voltage is applied, leading to rapid deterioration and eventual unusability.
Innovation Solution
The printer is designed with a configuration where head units with higher ejection performance are placed at the center and those with lower performance are placed at the edges, with lower drive voltages applied to the former to slow down degradation, and higher drive voltages applied to the latter, optimizing the usage frequency and extending the product life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If head units with higher ejection performance are placed at the center position, then printing quality at the center region is improved, but degradation of piezoelectric elements occurs more rapidly due to higher usage frequency
Solution Approach 1:
The patent applies local quality by assigning different drive voltages to head units based on their position and performance characteristics. Center head units that are used more frequently receive lower drive voltages to reduce degradation, while edge head units receive higher drive voltages. This localized differentiation of operating conditions optimizes both printing quality and extends the service life of piezoelectric elements in high-usage areas.
2Productivity
If higher drive voltage is applied to maintain performance of degraded piezoelectric elements, then ejection performance is maintained, but the elements degrade even faster leading to premature failure
Solution Approach 1:
The patent implements dynamics by making the drive voltage adjustable and position-dependent rather than uniform. The control unit dynamically selects appropriate drive voltages from multiple levels based on which head units are currently in use and their position in the array. This dynamic adjustment allows the system to maintain adequate ejection performance while preventing excessive degradation that would occur with consistently high voltage application.
3Device complexity
If uniform drive voltage is applied to all head units, then control simplicity is maintained, but center head units degrade faster due to higher usage frequency
Solution Approach 1:
The patent applies parameter changes by modifying the drive voltage parameter based on head unit position and usage patterns. Instead of using a single uniform voltage, the system implements multiple voltage levels (e.g., first drive voltage for center head units, second drive voltage for edge head units) and selectively applies them based on which head units are actively printing. This approach maintains reasonable control complexity while significantly improving the service life of piezoelectric elements in high-usage center positions.
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 effectively extends the service life of the printer by managing the usage frequency and drive voltage application, preventing premature degradation of piezoelectric elements, especially in high-frequency usage areas.
Implementation Method 1
Each piezoelectric element utilizes deformation generated in the piezoelectric layer (piezoelectric strain) when a prescribed drive voltage is applied across the two types of electrodes to generate a pressure wave in the corresponding pressure chamber of the channel module in order to eject ink from the corresponding nozzle.
Data Source
AI summary
An inkjet head includes a plurality of head units including a first head unit and a second head unit. Each head unit has a plurality of nozzles and a plurality of drive elements. The second head unit has an ejection performance of nozzles lower than an ejection performance of nozzles of the first head unit. The second head unit is farther from a center portion of the inkjet head than the first head unit is. A drive unit is configured to apply a drive voltage for generating energy to each of the plurality of drive elements included in each of the plurality of head units. The drive voltage applied to each of the plurality of drive elements included in the first head unit is lower than the drive voltage applied to each of the plurality of drive elements included in the second head unit.