Thermal Ink-Jet Ink Protective Layer Dissolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thermal ink-jet heads with insulating protective layers made of silicon nitride, silicon oxide, or silicon carbide suffer from dissolution during long-term storage, leading to reduced layer thickness, abnormal foaming, and ejection failures due to polyvalent metal precipitation and colorant interaction, which affects image quality and printing durability.
Innovation Solution
Incorporating a compound represented by a specific general formula that suppresses the dissolution of the protective layer, along with a substance that dissolves it, within the ink, maintaining a concentration between 1% to 30% by mass, to stabilize the protective layer and prevent ejection failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a protective layer is made thinner to improve thermal efficiency, then energy efficiency is improved, but the protection against mechanical and chemical damage deteriorates
Solution Approach 1:
The protective layer is formed as a composite structure comprising a silicon nitride layer and a silicon oxide layer. The silicon nitride layer provides mechanical strength and cavitation resistance, while the silicon oxide layer offers chemical stability and erosion resistance. This composite material approach allows the protective layer to be thin enough for thermal efficiency while maintaining sufficient protection against both mechanical and chemical damage.
2Reliability
If a protective layer is made thicker to improve protection against mechanical and chemical damage, then reliability is improved, but thermal efficiency deteriorates
Solution Approach 1:
The protective layer uses a composite structure with specific thickness ranges: the silicon nitride layer is 50-200 nm thick and the silicon oxide layer is 20-100 nm thick. This optimized composite structure provides sufficient mechanical and chemical protection while keeping the total thickness minimal to maintain thermal efficiency for ink ejection.
3Reliability
If the protective layer is made of materials stable against mechanical and chemical damage, then reliability is improved, but the materials are more difficult to form with existing semiconductor devices
Solution Approach 1:
The protective layer is formed as a composite of silicon nitride and silicon oxide, both of which are standard materials in semiconductor manufacturing. The layer is formed using existing semiconductor fabrication techniques, making the process compatible with current manufacturing capabilities while providing the required mechanical and chemical stability.
4Duration of action of stationary object
If ink contains substances that dissolve the protective layer, then ejection durability is improved, but the protective layer thickness reduces during storage
Solution Approach 1:
The protective layer uses a composite structure where the silicon nitride layer provides resistance to dissolution by ink components, while the silicon oxide layer provides chemical stability. This composite structure maintains layer thickness stability during storage while allowing controlled interaction with ink for ejection durability.
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 the dissolution of the protective layer, maintains ejection reliability, and ensures stable image formation even after long-term storage, reducing temperature increases and improving printing durability.
Implementation Method 1
a thermal ink-jet head provided with a heat generating portion which generates thermal energy for ejecting the ink from an ejection opening
Implementation Method 2
an ink which contains a substance that dissolves the protective layer and a compound having a specific chemical structure
Data Source
AI summary
An ink cartridge includes a thermal ink-jet head provided with a heat generating portion that generates thermal energy for ejecting the ink from an ejection opening, in which: the heat generating portion has, on its surface in contact with the ink, a protective layer containing at least one selected from the group consisting of a silicon oxide, a silicon nitride, and a silicon carbide; and the ink contains a substance that dissolves the protective layer and a compound represented by (R2)nA—. . . —N(R1)C(O)R3(R4)—(A) where A represents alkylene or alkenylene which forms a ring with a nitrogen atom, a carbonyl group and R3, R1 and R4 each represent hydrogen atom, hydroxyl, alkyl, alkenyl, acyl, carbamoyl, carboxyl or sulfonyl, R2 represents a group bonded to an arbitrary carbon atom of A and represents hydrogen atom, hydroxyl, alkyl, alkenyl, acyl, carbamoyl, carboxyl or sulfonyl, n represents 0 to 4, and R3 represents carbon or nitrogen atom, and a content X (% by mass) of the compound satisfies 1≦X≦30.