Inkjet Capping Mechanism Slit Design for Nozzle Maintenance
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Solution Overview
Problem
Inkjet printing devices face nozzle clogging due to ink drying and thickening during standby, leading to ink mist scattering and adherence to the inkjet head, which can cause image defects.
Innovation Solution
An inkjet printing device with a capping mechanism featuring a cap portion made of elastic material, including an annular wall with slits and a filter, that prevents ink droplets from remaining by guiding them away and ensuring effective suction and flushing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cap portion is used to cover the nozzle hole, then ink drying is prevented, but ink droplets may remain on the cap portion due to surface tension
Solution Approach 1:
The cap portion is divided into multiple functional regions: a hydrophilic region that attracts and guides ink droplets toward the nozzle, and a hydrophobic region that repels ink droplets to prevent them from adhering to the cap surface. This segmentation of surface properties resolves the contradiction by directing ink flow while preventing unwanted adhesion.
Solution Approach 2:
Different regions of the cap portion are assigned different wettability characteristics: the region near the nozzle opening is made hydrophilic to facilitate ink drainage, while the outer regions are made hydrophobic to prevent ink adhesion. This local differentiation of surface properties allows the cap to simultaneously manage ink flow and prevent droplet remaining.
2Ease of operation
If the cap portion is pressed against the lower surface of the inkjet head, then a closed space is formed for suction and flushing, but ink droplets may adhere to the peripheral wall portion
Solution Approach 1:
The peripheral wall portion of the cap is treated with hydrophobic properties to repel ink mist and prevent adhesion, while the region facing the nozzle maintains hydrophilic characteristics to facilitate ink drainage. This local quality differentiation allows the cap to form an effective closed space for suction and flushing while preventing harmful ink adhesion on its surfaces.
Solution Approach 2:
The cap portion utilizes the surface tension of ink that was previously causing harmful adhesion and converts it into a beneficial force by designing the hydrophilic region to guide ink droplets along the wall toward the nozzle for effective drainage. The surface tension becomes a driving force for ink removal rather than a cause of adhesion problems.
3Productivity
If a rectangular cap portion with a suction port is used, then ink suction and flushing are achieved, but clearances form when ink droplets dry and solidify on the cap
Solution Approach 1:
The cap portion employs different surface treatments in different regions: the peripheral and upper surfaces are made hydrophobic to prevent ink adhesion and drying, while the region near the suction port remains hydrophilic to facilitate ink drainage. This prevents ink droplets from drying and solidifying on the cap surface, eliminating the formation of clearances that would compromise sealing and reduce maintenance efficiency.
Solution Approach 2:
The cap portion is designed with hydrophobic surfaces that prevent ink adhesion before the ink can dry and solidify. By preemptively preventing ink droplet remaining through surface property control, the design eliminates the subsequent problem of clearance formation, ensuring continuous effective sealing and maintenance operation.
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 prevents ink droplets from remaining on the cap portion, reducing the likelihood of nozzle clogging and image defects by enhancing the wettability and repellency of the ink, ensuring reliable printing operations.
Implementation Method 1
due to the surface tension of the ink in the cap portion
Implementation Method 2
suction removal of ink from a nozzle of an inkjet head
Implementation Method 3
flushing process of ejecting ink from a nozzle of an inkjet head
Data Source
AI summary
An inkjet printing device includes: an ink head, having a nozzle hole opened in a nozzle surface; a carriage, being movable in a main scanning direction and in which multiple ink heads being arranged in the main scanning direction; and a capping mechanism. When the ink head is disposed at a standby position set within a movement range of the carriage, the capping mechanism brings the cap portion into contact with the nozzle surface to cover a region where the nozzle hole opened in the nozzle surface. The cap portion includes: an annular wall, surrounding a region where the nozzle hole opened in the nozzle surface; and a bottom wall portion, sealing an opening of the annular wall and being disposed with an interval from the nozzle surface. On an inner periphery of the annular wall, a slit directed toward the bottom wall portion is provided over the entire periphery.