Liquid Ejection Nozzle Testing via Common Portion
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Solution Overview
Problem
Existing liquid ejection devices face challenges in performing nozzle testing without disrupting the printing process, as either requiring multiple testing portions for each nozzle or being unable to test specific nozzles while others are in use.
Innovation Solution
A liquid ejection device with a common ejection testing portion that can test a specific nozzle during its ejection cycle, using a drive signal with a testing period, and switches to isolate the nozzle for testing while others are driven for printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual ejection testing portions are provided for each nozzle, then each nozzle can be tested independently, but the number of testing portions increases significantly
Solution Approach 1:
The patent implements a common ejection testing portion that can test multiple nozzles sequentially through time-division multiplexing. The testing portion is shared among all nozzles by controlling piezoelectric elements to eject liquid drops onto the same testing region at different time slots, thereby reducing the number of testing portions while maintaining individual testing capability.
2Device complexity
If a common ejection testing portion is used for all nozzles, then the device complexity is reduced, but specific nozzles cannot be tested when other nozzles are being driven for printing
Solution Approach 1:
The patent employs periodic time-division multiplexing where the common ejection testing portion alternates between testing different nozzles. Each nozzle is assigned specific time slots within a periodic cycle to eject liquid drops onto the shared testing portion, enabling independent testing of specific nozzles even when others are being used for printing, thus achieving both simplicity and flexibility.
3Reliability
If nozzle testing is performed, then nozzle functionality can be verified, but the printing process must be interrupted
Solution Approach 1:
The patent performs nozzle testing during idle periods or in conjunction with printing operations by utilizing the common ejection testing portion in time-division mode. The testing is scheduled in advance during time slots when the printing head is not actively printing, allowing nozzle verification without interrupting the overall printing process and maintaining productivity.
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
Enables reliable and accurate nozzle testing without interrupting the printing process, reducing the need for multiple testing portions and allowing testing during active ejection cycles.
Implementation Method 1
a plurality of piezoelectric elements, the nozzles being arranged to eject a liquid by driving of the piezoelectric elements
Implementation Method 2
sense residual oscillation of the pressure chambers subsequent to driving of the piezoelectric elements, and to perform nozzle ejection testing based on the residual oscillation thereof
Data Source
AI summary
A liquid ejection device includes a plurality of nozzles, a plurality of piezoelectric elements, a drive signal generating portion and a common ejection testing portion. The nozzles are arranged to eject a liquid. The piezoelectric elements are provided in respective correspondence to the nozzles. The drive signal generating portion is arranged to generate a drive signal which repeats for each ejection cycle in which the nozzles eject the liquid onto a pixel, the drive signal having a testing period within each ejection cycle. The common ejection testing portion is provided in common to the nozzles. One of the piezoelectric elements corresponding to the nozzle to be tested is driven within a given ejection cycle of the drive signal, whereupon the nozzle to be tested is tested by the common ejection testing portion during the testing period of the same given ejection cycle.