Inkjet Head Adhesive Bonding via UV Pre-Curing
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Solution Overview
Problem
The challenge in manufacturing inkjet heads is to achieve adhesive bonding with no voids, high work efficiency, and excellent adhesive strength while preventing adhesive flow into unnecessary areas and ensuring resistance to solvent inks, which existing methods fail to address effectively due to issues with adhesive viscosity, curing efficiency, and ink leakage.
Innovation Solution
A method involving the use of an adhesive containing novolac type epoxy resin, a photo-cationic polymerization initiator, and a microencapsulated thermosetting agent, with sequential application, light irradiation, and controlled heating to cure the adhesive, ensuring 5-50% novolac type epoxy resin by mass, and incorporating a silane coupling agent for enhanced bonding and solvent resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating treatment is carried out to raise glass transition point of adhesive for preventing ink swelling, then adhesive resistance to ink is improved, but viscosity of adhesive falls and adhesive flows into nozzle portion
Solution Approach 1:
The patent applies preliminary action by conducting UV irradiation to partially cure the adhesive before thermal curing. This preliminary UV curing creates a gel structure that maintains adhesive viscosity during subsequent heating, preventing adhesive from flowing into nozzle portions while still allowing the thermal curing process to raise the glass transition point for ink resistance.
Solution Approach 2:
The patent changes the curing parameters by introducing UV irradiation as a new curing mechanism alongside thermal curing. By controlling UV irradiation dose and timing, the adhesive achieves partial curing with increased viscosity before heating, thereby maintaining dimensional stability during thermal processing while achieving the required glass transition point for solvent ink resistance.
2Manufacturing precision
If coating amount of adhesive is reduced to prevent inflow to nozzle area, then adhesive flow is controlled, but void between nozzle plate and flow path component increases causing ink leakage
Solution Approach 1:
The patent applies preliminary UV irradiation to the adhesive before final assembly and thermal curing. This preliminary action causes the adhesive to gel and increase in viscosity, which prevents excessive flow into nozzle areas during assembly while still maintaining enough fluidity to fill voids and adhere properly to bonding surfaces, thereby preventing ink leakage.
Solution Approach 2:
The patent changes the adhesive's physical state through UV irradiation, transforming it from a low-viscosity liquid to a gel state with higher viscosity. This parameter change allows the adhesive to be applied in controlled amounts that prevent nozzle clogging while still providing sufficient material to fill bonding voids and ensure complete coverage for leak prevention.
3Reliability
If amount of adhesive is increased to eliminate void, then void between components is reduced, but adhesive overflowing from gap increases and flows into nozzle area
Solution Approach 1:
The patent applies preliminary UV irradiation to increase adhesive viscosity before assembly. This allows using a larger amount of adhesive to ensure complete void elimination during bonding, while the pre-gelled adhesive maintains its shape and does not excessively overflow into nozzle areas during the assembly process.
4Device complexity
If conventional adhesive curing method is used, then manufacturing process is simple, but work efficiency is low due to long curing time and curved ejection
Solution Approach 1:
The patent merges UV curing and thermal curing into a single integrated process. UV irradiation provides rapid initial curing that sets the adhesive in place, while subsequent thermal curing completes the curing process and achieves the required glass transition point. This combination eliminates the need for separate curing steps and prevents curved ejection, significantly improving work efficiency.
Solution Approach 2:
The patent implements continuous curing action by applying UV irradiation immediately after adhesive application, followed by continuous thermal curing. This continuous process eliminates idle time between curing steps and ensures the adhesive progresses through curing stages without interruption, maximizing productivity and preventing defects like curved ejection.
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
This method eliminates jet failures, enhances work efficiency, prevents ink leakage, and provides excellent adhesive strength and solvent resistance, ensuring reliable inkjet head performance.
Implementation Method 1
a step of irradiating the protruding portion of the adhesive with light
Implementation Method 2
a heating step
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed is a method for manufacturing an head, wherein a process of bonding a plurality of members with an adhesive containing a microcapsulated thermosetting agent sequentially has: a step of applying the adhesive to one of the members; a step of bonding the members; a step of irradiating the protruding portion of the adhesive with light; and a heating step. Thus, the inkjet head, which eliminates a jet failure due to having the adhesive flow into a channel, has a high work efficiency and excellent bonbing characteristics, eliminates ink leakage from an ink channel due to peeling of the members and the adhesive from each other, and has excellent durability also to a solvent ink, is provided