Inkjet Head Wiring Segmentation for Noise Reduction
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Solution Overview
Problem
The existing inkjet head designs face complications and deterioration in discharge characteristics due to the complexity and thinness of common wires on flexible substrates, which are prone to noise and voltage drops, affecting the reliability and efficiency of ink ejection.
Innovation Solution
The design incorporates a configuration where flexible substrates are connected in parallel between the head substrate and a printed board, with a common wire extending from the head substrate and connected to reference potential, and separate common connection wires on each flexible substrate, reducing wire complexity and thickness, and improving electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the common wire is disposed in a separate path not on the flexible substrate, then wiring complexity is reduced, but the wire becomes long and complicated, leading to noise and voltage drop
Solution Approach 1:
The patent divides the common wire into multiple segments: a first common wire on the head substrate, second common wires on separate flexible substrates, and connection wires linking them. This segmentation allows each segment to be optimized independently - the head substrate common wire can be short and thick, while flexible substrate common wires can be thin but are kept short through proper positioning.
Solution Approach 2:
The patent transitions from a single-plane wiring approach to a multi-dimensional structure by placing common wires on different substrates (head substrate and flexible substrates) and connecting them through space. This spatial distribution reduces wiring complexity on each individual substrate while maintaining overall connectivity.
2Device complexity
If the common wire is disposed through the driving IC chip on the flexible substrate, then wiring complexity is reduced, but noise propagation occurs and wire thickness must be reduced, causing voltage drop
Solution Approach 1:
The patent extracts the common wire function from the flexible substrate alone and distributes it across multiple substrates. The head substrate carries a dedicated common wire that is electrically connected to the flexible substrate common wires, separating the high-current common path from the signal-carrying flexible substrate to reduce noise interference.
Solution Approach 2:
The head substrate acts as an intermediary carrier for the common wire, mediating between the inkjet elements and the flexible substrate. This intermediary structure provides a stable, thick common wire path that reduces voltage drop and isolates noise from the flexible substrate circuits.
3Reliability
If the common wire is widened to prevent voltage drop, then discharge characteristics improve, but the mounting area of the driving IC chip increases, hindering apparatus size reduction
Solution Approach 1:
The patent segments the common wire across different substrates, allowing the head substrate to accommodate a thick common wire for low voltage drop, while flexible substrates use thinner common wires that occupy less mounting area. The connection wires bridge these segments efficiently.
Solution Approach 2:
The patent applies different wire thicknesses to different locations: thick common wires on the head substrate where space is available and low voltage drop is critical, and thinner common wires on flexible substrates where mounting area is constrained. This local optimization balances performance and compactness.
Data Source
AI summary
An ink jet head includes a head substrate, a printed board, and a plurality of flexible substrates connected in parallel to each other between the head substrate and the printed board. The head substrate includes a plurality of ink jet elements, and a common wire extending from an edge of the head substrate and electrically connected to the ink jet elements in common. The printed board includes a reference potential wire through which a reference potential is set to the ink jet head. A first one of the flexible substrates at a first end of an arrangement of the flexible substrates and a second one of the flexible substrates at a second end of the arrangement of the flexible substrates opposite to the first end each has a common connection wire electrically connected between the common wire and the reference potential wire.