Inkjet Head Cap Venting for Humidity and Meniscus Stability
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Solution Overview
Problem
In inkjet recording apparatuses using water-based ink, moisture evaporation from the ink nozzle leads to increased viscosity, causing ejection failure and clogging, and temperature changes inside a sealed cap can result in condensation and meniscus collapse.
Innovation Solution
A cap unit comprising a cap, a tank, first and second pipes, a pump, and a vent port, which allows for controlled air circulation to maintain humidity and stabilize temperature and pressure within the cap, preventing condensation and meniscus collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealed cap is used to prevent moisture evaporation from the ink nozzle, then ink viscosity increase is suppressed, but condensation occurs on the nozzle surface and meniscus collapse happens due to temperature changes
Solution Approach 1:
The invention extracts the harmful sealed environment by providing a vent port that communicates the interior of the cap with the exterior atmosphere. This allows the cap interior to be open rather than sealed, preventing condensation and meniscus collapse while still maintaining a humid environment to suppress ink viscosity increase through the humidifying liquid and air circulation system
Solution Approach 2:
The invention introduces air circulation as an intermediary mechanism between the humidifying liquid and the ink nozzle. The pump circulates air from the cap interior through the humidifying liquid and back, creating a controlled humid environment that prevents ink viscosity increase without the harmful effects of a completely sealed cap
2Object-affected harmful factors
If air circulation is introduced to prevent condensation, then meniscus stability is improved, but ink humidity control becomes less effective
Solution Approach 1:
The invention ensures continuous useful action by maintaining constant air circulation through the humidifying liquid using the pump. This continuous circulation continuously humidifies the air that contacts the ink nozzle, ensuring both meniscus stability and effective humidity control are maintained simultaneously
Solution Approach 2:
The air circulation system creates a feedback mechanism where air that has contacted the ink and picked up moisture is continuously circulated back through the humidifying liquid. This feedback loop maintains optimal humidity levels at the nozzle while the vent port ensures pressure equalization to prevent condensation
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
The cap unit effectively suppresses ink viscosity increases and prevents condensation and meniscus collapse by regulating air circulation, ensuring stable ink ejection.
Implementation Method 1
moisture evaporates from the ink in a nozzle while printing is not performed, resulting in an increase in viscosity
Implementation Method 2
if a temperature inside the cap changes, condensation may occur on the nozzle surface
Data Source
AI summary
A cap unit includes a cap, a tank, a first pipe, a second pipe, a pump, and a vent port. The cap is attached to and detached from a nozzle surface of an inkjet head. The tank stores humidifying liquid. The first pipe and the second pipe connect the cap and the tank. The pump is provided in the first pipe and pumping air in the tank into the cap. The vent port is provided in the cap.