Printhead Meniscus Anchor for Controlled Priming
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Solution Overview
Problem
Pagewidth inkjet printheads face challenges in ink supply due to high flow rates and complex conduit networks, leading to issues like nozzle flooding and inconsistent priming, particularly exacerbated by the length and complexity of ink conduits.
Innovation Solution
Incorporating fluidic dampers containing gas for pressure pulse dissipation within the ink conduits, using weir formations to preferentially prime upstream sections, and distributing pulse dampers along the printhead to mitigate pressure spikes, along with optimized ink conduit designs and support structures like liquid crystal polymer (LCP) moldings to enhance ink supply and priming efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pagewidth printhead design is used to increase print speed, then productivity is improved, but ink supply reliability deteriorates due to high flow rates and complex conduit networks
Solution Approach 1:
The ink supply system is segmented into multiple independent conduit branches, each with its own meniscus anchor feature. This segmentation allows independent control of ink flow in each branch, preventing flooding in one branch from affecting others, thus maintaining reliability at high print speeds
Solution Approach 2:
A meniscus anchor feature acts as an intermediary element within each conduit branch, positioned to interact with the ink meniscus and control its movement. This intermediary structure prevents uncontrolled meniscus advancement that causes flooding, ensuring reliable ink supply to the printhead
2Device complexity
If conduit width is reduced to less than a millimeter, then device complexity is reduced, but ink flow control deteriorates causing meniscus bypass and inconsistent priming
Solution Approach 1:
The meniscus anchor feature introduces a localized structural variation within the conduit at specific positions. This local quality change creates a preferential path for the ink meniscus to follow, ensuring consistent priming behavior in narrow conduits without increasing overall device complexity
Solution Approach 2:
The meniscus anchor feature modifies the local geometry parameters of the conduit, creating a step or ledge structure that changes the meniscus curvature and contact line position. This parameter change ensures the meniscus advances controllably through narrow conduits, improving priming consistency
3Productivity
If pagewidth printhead with long conduit network is used, then productivity is improved, but harmful factors increase due to pressure pulses causing nozzle flooding
Solution Approach 1:
The meniscus anchor feature is positioned upstream in each conduit branch to preemptively control meniscus movement before pressure pulses can cause uncontrolled advancement. This preliminary action prevents flooding by establishing controlled meniscus positions in advance
Solution Approach 2:
The meniscus anchor feature converts the harmful effect of pressure pulses into a beneficial controlled meniscus advancement. By providing a defined path and resistance point, the anchor allows pressure pulses to advance the meniscus in a controlled manner rather than causing flooding
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
These solutions effectively manage pressure pulses, prevent nozzle flooding, and ensure consistent priming across the printhead array, enhancing print quality and reliability by maintaining a compact design while maintaining high print speeds.
Implementation Method 1
a fluidic damper containing gas for compression by pressure pulses in the ink within the ink conduits to dissipate the pressure pulse
Implementation Method 2
a weir formation to partially obstruct ink flow; when priming the printhead, the weir formation preferentially primes an upstream section the ink conduit
Data Source
AI summary
A printhead for an inkjet printer that has a printhead integrated circuit (IC) with an array of nozzles for ejecting ink, and a support structure for mounting the printhead IC within the printer. The support structure has ink conduits for supplying the array of nozzles with ink, the ink conduits have a meniscus anchor for pinning part of an advancing meniscus of ink to divert the advancing meniscus from a path the advancing meniscus would otherwise take. If a printhead consistently fails to prime correctly because a meniscus pins at one or more points, then the advancing meniscus can be directed so that the advancing meniscus does not contact these critical points. Deliberately incorporating a discontinuity into an ink conduit immediately upstream of the problem area can temporarily pin to the meniscus and skew the meniscus to one side of the conduit and away from the undesirable pinning point. Once flow has been initiated into the side branch or downstream of the undesirable pinning point, it is not necessary for the anchor to hold the ink meniscus any longer and priming can continue.