Dry Printhead Priming via Vacuum Capping
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Solution Overview
Problem
Dry-shipped inkjet printheads pose challenges for ink delivery systems during priming, as actuating the pump tends to suck air into the printhead nozzles instead of drawing fresh ink, especially in longer printheads, due to the lack of a perfect hermetic seal provided by conventional cappers.
Innovation Solution
A system that primes dry printheads by capping the printhead with a capper and applying controlled suction via a vacuum source to prevent air from entering the nozzles, allowing ink to be drawn into the printhead through the inlet port, while the pump circulates ink around the closed fluidic loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pump is actuated to draw ink into a dry printhead, then ink delivery is enabled, but air is sucked into the printhead nozzles instead of ink
Solution Approach 1:
A capper is introduced as an intermediary device between the printhead and the environment. The capper includes a capping chamber that seals around the printhead nozzles, creating an isolated environment. This intermediary structure prevents air from entering the nozzles during pump operation while allowing ink to be delivered through the printhead.
Solution Approach 2:
The capping chamber creates a controlled, air-free environment around the printhead nozzles. By maintaining this inert atmosphere during pump operation, the system prevents air from being drawn into the nozzles, ensuring that only ink enters the printhead when the pump is actuated.
2Object-affected harmful factors
If conventional capping is used, then the printhead is sealed, but air can still enter through imperfect hermetic seals
Solution Approach 1:
The capping chamber serves as an intermediary sealing structure that encompasses the entire printhead nozzle area. Rather than relying on a single point hermetic seal, this chamber provides distributed sealing contact, compensating for imperfections and ensuring complete air exclusion during pump operation.
3Object-generated harmful factors
If dry printheads are shipped, then leaking and spilling is prevented, but priming becomes challenging
Solution Approach 1:
The capper with capping chamber acts as an intermediary device that enables safe dry shipment while facilitating priming. During shipment, the capper protects the dry printhead. During priming, the same capper structure is utilized to prevent air ingress, making the transition from shipping to priming operations seamless and reliable.
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 effective priming of dry printheads by ensuring ink is drawn into the printhead without air ingress, even in longer models, by maintaining a controlled vacuum pressure within the capping chamber that overcomes the pressure exerted by the pump, thus facilitating reliable ink delivery.
Implementation Method 1
a vacuum source for applying suction to a capping chamber of the capper
Implementation Method 2
a pump operably connected to the downstream ink line
Data Source
Figure 1
Figure 2
AI summary
A system for priming a dry inkjet printhead (4). The system includes: the inkjet printhead (4) having an inlet port (8) connected to an upstream ink line and an outlet port (14) connected to a downstream ink line; a pump (40) operably connected to the downstream ink line; a capper (200) engaged with printhead; a vacuum source for applying suction to a capping chamber (202) of the capper (200); and a control system for coordinating actuation of the pump and the vacuum source. In use, the pump (40) is actuated simultaneously with the vacuum source, thereby drawing ink through the printhead (4) from the inlet port to the outlet port and priming the printhead.