Liquid Ejecting Head Fixing Plate Warping Prevention
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Solution Overview
Problem
Liquid ejecting heads face damage to nozzle surfaces due to warping of the fixing plate's side surfaces when a recording medium collides, causing stress that can lead to misalignment and deformation of the head units.
Innovation Solution
A liquid ejecting head design with a fixing plate that includes multiple gaps filled with different types of fillers, where a higher hardness filler is used in the gap further from the bottom surface to prevent warping and a lower hardness filler in the gap closer to the bottom surface to manage contraction stress, along with ribs to define the filling range and prevent filler overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the filler hardness is reduced further from the bottom surface to improve ease of manufacture and reduce stress, then the side surfaces become more prone to warping when subjected to external force, but this increases the risk of damage to the nozzle surface
Solution Approach 1:
The patent applies local quality by dividing the filler into two distinct types with different hardness levels positioned at different locations. The first filler with lower hardness is placed closer to the bottom surface to reduce stress during curing, while the second filler with higher hardness is placed further away to prevent warping of side surfaces when subjected to external forces like recording medium collision.
Solution Approach 2:
The patent uses composite materials by combining two different filler materials with distinct properties. The first filler material has lower hardness to minimize curing stress and deformation, while the second filler material has higher hardness to provide structural support and prevent warping. This composite approach allows the fixing plate to simultaneously achieve ease of manufacture and resistance to warping.
2Device complexity
If a single layer of filler is used to simplify the structure, then the manufacturing process is easier, but the fixing plate cannot effectively resist both curing stress and external impact forces
Solution Approach 1:
The patent applies local quality by positioning different filler types in specific locations within the gaps. The lower hardness first filler is positioned to manage curing stress near the bottom surface, while the higher hardness second filler is positioned further away to specifically address impact resistance from recording medium collision. This spatial differentiation of material properties optimizes both stress management and impact resistance.
Solution Approach 2:
The patent implements beforehand cushioning by pre-positioning the two-layer filler structure before the fixing plate is subjected to operational stresses. The lower hardness first filler acts as a cushioning layer that absorbs curing stress and prevents deformation, while the higher hardness second filler is pre-positioned to provide structural reinforcement against future impact forces from recording medium collision.
3Reliability
If the fixing plate is made larger to prevent filler overflow, then filler containment is improved, but the overall device size increases and durability is compromised
Solution Approach 1:
The patent applies preliminary action by providing ribs that protrude from the head units toward the side surfaces of the fixing plate before the filler is applied. These ribs create predefined boundaries that guide and contain the filler within the gaps, preventing overflow without requiring an enlarged fixing plate. The ribs are positioned in advance to establish the exact filling limits.
Solution Approach 2:
The patent uses ribs as an intermediary element between the head units and the filler material. The ribs protrude into the gaps to act as physical barriers that mediate the filler containment, allowing the filler to be properly contained within the gaps without expanding the overall fixing plate area. This intermediary structure enables precise filler positioning and prevents overflow.
Data Source
AI summary
A liquid ejecting head includes a fixing plate which includes a bottom surface which is fixed onto the nozzle surface of each of a plurality of head units which are provided to line up in a state in which a first gap is formed along a first direction, and a first side surface which extends from an edge of the bottom surface which is positioned closer to an outside in the first direction than the lined-up head units to the head unit side. The fixing plate includes a second gap which is formed between the first side surface and the head units which are positioned at ends in the first direction among the head units. The liquid ejecting head also includes a second outer circumferential mold which fills at least a portion of the first gap, and a third outer circumferential mold which fills at least a portion of the second gap. The third outer circumferential mold fills the second gap at a position which is distanced further from the bottom surface than the second outer circumferential mold in a direction which is perpendicular to the bottom surface, and a hardness of the third outer circumferential mold is higher than a hardness of the second outer circumferential mold.