Flexible Printed Circuit Folding for Liquid Ejection Head Width Reduction
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Solution Overview
Problem
Conventional liquid ejection heads are limited in downsizing and cost reduction due to the configuration of flexible printed circuits, which restricts the miniaturization of image forming apparatuses and increases manufacturing costs.
Innovation Solution
The design incorporates multiple driving element rows with flexible printed circuits arranged to face each other, with input terminal parts folded and connected to a wiring board, allowing for reduced width and efficient packaging without increasing the head's width, and integrating the ink jet head with the ink tank for a compact cartridge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional FPC configuration with connector parts facing each other is used, then electrical connection is achieved, but the width of the recording head cannot be reduced
Solution Approach 1:
The patent applies dimensionality change by transitioning from a two-dimensional planar arrangement where FPCs face each other to a three-dimensional folded configuration. The FPCs are folded along imaginary lines to position connector parts on opposite sides of the head in the depth direction rather than facing each other in the width direction, enabling width reduction while maintaining electrical connectivity.
Solution Approach 2:
The patent implements nesting by folding the FPCs into the internal space of the head assembly. The flexible printed circuits are folded back and positioned within the head structure, allowing the connector parts to be received by connector housings on the opposite side without increasing the external width of the head.
2Ease of manufacture
If FPCs are folded back to reduce part cost, then manufacturing cost is reduced, but downsizing of carriage and head is insufficient
Solution Approach 1:
The patent introduces asymmetry in the FPC configuration by having FPCs fold in different directions and positions. The first and second FPCs are folded along different imaginary lines and positioned asymmetrically within the head structure, allowing optimized space utilization that simultaneously achieves cost reduction through folding and significant downsizing of the carriage.
3Productivity
If multiple driving element rows are used to improve recording speed and image quality, then recording performance is improved, but the number of parts and manufacturing cost increase
Solution Approach 1:
The patent applies universality by designing a standardized FPC and connector assembly that can be replicated for multiple driving element rows. The same basic FPC structure with folded configuration and connector housing is used for both the first and second driving element rows, allowing improved recording speed through multiple rows while avoiding proportional increases in part complexity and manufacturing cost.
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 configuration enables the downsizing of both the liquid ejection head and the image forming apparatus, reducing manufacturing costs and improving the compactness of the system while maintaining high-speed printing capabilities.
Implementation Method 1
a piezoelectric actuator that generates energy for ejecting a liquid droplet from the nozzle
Data Source
AI summary
A liquid ejection head is disclosed that includes piezoelectric elements constituting driving element rows in which plural driving piezoelectric element columns that generate energy for ejecting liquid droplets from nozzles are arranged side by side; a wiring board arranged on the side opposite to a surface in which the nozzles are formed; and two sheets of flexible printed circuits that are provided to correspond to the piezoelectric elements and have output terminal parts connected to the plural driving piezoelectric element columns and input terminal parts connected to the wiring board, the input terminal parts being drawn to the side of the wiring board. The flexible printed circuits are arranged facing each other with their input terminal parts not facing each other, and the input terminal parts of the flexible printed circuits are folded in a direction where the flexible printed circuits face each other and are connected to the wiring board.