Ink jet recording apparatus
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Solution Overview
Problem
Ink jet recording apparatuses with cap members suffer from missing dots due to air bubbles forming during nozzle cap opening and closing, especially when the ink composition's surface tension is lowered for improved coloring properties, leading to unsatisfactory performance in suppressing dot occurrence.
Innovation Solution
An aqueous ink composition with a surface tension of 40 mN/m or less, containing a wax with a melting point of 100°C or more, and a cap member with a silicone defoamer coating film on the nozzle contact surface are used to prevent foaming and missing dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the surface tension of the ink composition is lowered to improve coloring properties, then the coloring properties of recorded articles are improved, but air bubbles are readily generated during cap opening/closing and suction, causing missing dots
Solution Approach 1:
A silicone defoamer coating film is applied to the cap member's contact surface with the nozzle as an intermediary substance. This coating prevents direct harmful interaction between the low-surface-tension ink and the cap member, suppressing air bubble generation while maintaining the ink's low surface tension for good coloring properties
Solution Approach 2:
The surface tension of the ink composition is specifically controlled to be 40 mN/m or less to improve coloring properties, while a silicone defoamer coating is applied to the cap member to counteract the harmful effects of this parameter change, preventing air bubble formation despite the low surface tension
2Reliability
If a cap member is used to protect the nozzle, then nozzle protection is improved, but air bubbles are generated within the cap member during operation, causing discharge failure
Solution Approach 1:
The silicone defoamer coating film serves as an intermediary layer between the cap member and the ink, preventing the generation of air bubbles that would otherwise form due to the interaction between the ink and the cap member's contact surface
Solution Approach 2:
The silicone defoamer, which is specifically designed to suppress foaming and air bubble generation, is applied to the cap member contact surface. This converts the potentially harmful effect of air bubble formation into a beneficial outcome by preventing the very problem it was designed to address
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 reduces the occurrence of missing dots while maintaining excellent coloring properties by preventing the dissolution of the silicone defoamer and maintaining its defoaming ability, even when the ink composition's surface tension is lowered.
Implementation Method 1
the cap member has a coating film containing a silicone defoamer on a contact surface with the nozzle
Implementation Method 2
the aqueous ink composition contains a wax having a melting point of 100°C or more
Implementation Method 3
the aqueous ink composition has a surface tension of 40 mN/m or less
Data Source
Figure 1
Figure 2
AI summary
An ink jet recording apparatus (1) includes: an aqueous ink composition; a liquid ejecting head (3) having a nozzle for discharging the aqueous ink composition; and a cap member (20) for protecting the nozzle, where: the aqueous ink composition has a surface tension of 40 mN/m or less; the aqueous ink composition contains a wax having a melting point of 100°C or more; and the cap member has a coating film containing a silicone defoamer on a contact surface with the nozzle.