Inkjet Printhead Pad Reduction via Shift Register Addressing
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Solution Overview
Problem
As the number of drop generators in inkjet printheads increases to improve printing speed and quality, the number of input pads required also increases, leading to complex printhead die layouts and higher costs, necessitating a reduction in input pads while maintaining printing performance.
Innovation Solution
The implementation of a pre-charged firing cell array with a shift register and address generator that allows for efficient addressing and energization of drop generators using a reduced number of input pads, enabling sequential activation of drop generators to minimize the number of input pads required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of drop generators is increased to improve printing speed and quality, then printing performance is improved, but the number of input pads increases leading to complex layouts and higher costs
Solution Approach 1:
The printhead die is divided into multiple primitives, where each primitive contains multiple drop generators that share common power and ground leads. This segmentation allows efficient grouping of drop generators into manageable units with shared resources, reducing the total number of input pads required while maintaining high drop generator density for improved printing performance
Solution Approach 2:
Common power and ground leads are designed to serve multiple drop generators within each primitive simultaneously. These universal leads provide electrical connection to multiple firing resistors through the FET array, reducing the number of dedicated input pads needed while supporting a high number of drop generators for enhanced printing speed and quality
2Ease of manufacture
If the number of input pads is reduced to lower costs and simplify layouts, then manufacturing cost is reduced, but the number of drop generators that can be energized is limited
Solution Approach 1:
The electrical connection architecture transitions from a one-to-one mapping between input pads and drop generators to a many-to-one relationship where multiple drop generators share common power and ground leads. This dimensional change in the connection topology allows a reduced number of input pads to energize a high number of drop generators, lowering manufacturing costs while maintaining high drop generator quantities for improved printing performance
3Ease of operation
If each firing resistor is coupled to a corresponding input pad to simplify the circuit, then circuit simplicity is improved, but the number of input pads increases making it impractical for high numbers of firing resistors
Solution Approach 1:
Multiple power and ground leads are merged into common shared leads that serve multiple primitives and their associated drop generators. This merging of electrical connections reduces the total number of input pads required while maintaining organized, manageable circuit structures through the primitive grouping architecture, making it practical to support a high number of firing resistors with fewer input pads
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 solution allows for a significant reduction in the number of input pads while maintaining high printing quality and speed by efficiently managing the energization of drop generators, thereby simplifying printhead die layouts and reducing costs.
Implementation Method 1
The ink is heated with small electric heaters, such as thin film resistors referred to herein as firing resistors. Heating the ink causes the ink to vaporize and be ejected through the nozzles.
Implementation Method 2
Heating the ink causes the ink to vaporize and be ejected through the nozzles.
Data Source
AI summary
A fluid ejection device includes a first fire line adapted to conduct a first energy signal having energy pulses, a second fire line adapted to conduct a second energy signal having energy pulses, a first address generator configured to provide first address signals, a second address generator configured to provide second address signals, first drop generators and second drop generators. The first drop generators are electrically coupled to the first fire line and configured to respond to the first energy signal to eject fluid based on the first address signals. The second drop generators are electrically coupled to the second fire line and configured to respond to the second energy signal to eject fluid based on the second address signals.