Pivotable Capping Station for Inkjet Printhead Viscosity Control
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Solution Overview
Problem
Inkjet imaging devices face challenges in maintaining low viscosity of ink at nozzles during periods of printhead inactivity, leading to clogging due to evaporation of quickly drying inks, which reduces the effectiveness of purging and increases the number of non-operational inkjets.
Innovation Solution
A capping station with pivotable members and a controller-operated actuator that moves to expose and cover the printhead receptacle, using hydrophilic and hydrophobic materials to form an ink film, keeping the ink at a low viscosity state by minimizing evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the printhead is left exposed during inactivity, then access for printing is maintained, but ink evaporates from the nozzles causing viscosity increase and clogging
Solution Approach 1:
The patent uses a flexible cap member that can be moved between open and closed positions to cover the printhead nozzles. This flexible film/shell structure prevents ink evaporation while maintaining ease of access during printing operations, resolving the contradiction between operational accessibility and nozzle functionality preservation.
Solution Approach 2:
The cap member is designed to be dynamically movable between open and closed states rather than being fixed. This dynamic mechanism allows the system to adapt between two operational modes: open for printing access and closed for preserving ink viscosity, thus resolving the contradiction between ease of operation and reliability.
2Reliability
If the printhead is covered to prevent evaporation, then ink viscosity is maintained, but access for printing is blocked
Solution Approach 1:
The movable cap member enables dynamic switching between covered and exposed states. When covered, ink viscosity is maintained; when opened, printing access is restored. This dynamic design resolves the contradiction by allowing the system to occupy different states based on operational requirements.
Solution Approach 2:
The cap member is positioned to automatically cover the printhead when not in use, performing the protective action in advance before evaporation can occur. This preliminary protection maintains ink viscosity stability while not interfering with printing operations when the cap is opened.
3Reliability
If purging is performed frequently to clear clogged nozzles, then nozzle functionality is restored, but ink consumption increases
Solution Approach 1:
The cap member prevents the harmful process of evaporation before it can cause nozzle clogging. By maintaining ink viscosity stability through evaporation prevention, the system eliminates the need for frequent purging operations, thus resolving the contradiction between nozzle operability and ink consumption.
Solution Approach 2:
The system converts the potential harm of ink evaporation into a benefit by using the cap member to control the evaporation process. This prevents viscosity increase and nozzle clogging, reducing the need for purging and thereby decreasing ink consumption while maintaining nozzle operability.
4Reliability
If the cap remains closed for extended periods, then evaporation is minimized, but ink may still dry at the edges due to thin film formation
Solution Approach 1:
The system employs periodic purging operations at scheduled intervals rather than continuously. This periodic action removes ink from the nozzles and redeposits it to maintain a fresh ink film, preventing edge drying while the cap remains closed for most of the time, thus resolving the contradiction between viscosity maintenance and edge drying prevention.
Solution Approach 2:
The purging system uses the printer's own ink supply to clean and refresh the nozzle ink film. By periodically ejecting and redepositing ink, the system self-maintains the ink film quality at nozzle edges without requiring external intervention, preventing edge drying while maintaining overall ink viscosity.
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 solution effectively maintains ink viscosity, reducing the need for frequent purging and minimizing nozzle clogging, thereby enhancing the operational status of inkjets after periods of inactivity and conserving ink for subsequent printing.
Implementation Method 1
using hydrophilic and hydrophobic materials to form an ink film, keeping the ink at a low viscosity state by minimizing evaporation
Implementation Method 2
A capping station with pivotable members and a controller-operated actuator that moves to expose and cover the printhead receptacle
Data Source
AI summary
An inkjet printer is configured with capping stations for storing printheads in the printer during periods of printer inactivity so the viscosity of the ink in the nozzles of the inkjets of the printheads does not increase significantly. Each capping station has a printhead receptacle with an opening corresponding to a perimeter of a printhead, a pair of members pivotably mounted to the printhead receptacle so the members can move between a first position where the members expose the opening of the printhead receptacle and a second position where the members cover the opening of the printhead receptacle, and an actuator operatively connected to the pair of members to move the members between the first position and the second position. A controller is operatively connected to the actuator to operate the first actuator to move the members between the first position and the second position.