Firing Cell Circuitry for Inkjet Printhead Pad Reduction
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Solution Overview
Problem
The increasing number of drop generators in inkjet printheads requires a corresponding increase in input pads, which becomes impractical and costly, and affects printing quality and speed.
Innovation Solution
The implementation of pre-charged firing cells and double data rate firing cell circuits, which allow for the energization of multiple drop generators with fewer input pads by using pre-charge and select signals to manage data and address signals efficiently, reducing the need for additional input pads.
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 required increases making the design impractical and costly
Solution Approach 1:
The printhead is divided into multiple primitives, where each primitive contains multiple drop generators that share common power and address leads. This segmentation allows multiple drop generators to be controlled through fewer input pads, resolving the contradiction between printing performance and device complexity
Solution Approach 2:
The common power lead and address leads serve multiple drop generators simultaneously within each primitive. This multi-functionality reduces the total number of input pads required while maintaining the ability to independently control each drop generator, enabling higher productivity without proportionally increasing device complexity
2Ease of manufacture
If the number of input pads is reduced to lower cost and complexity, then manufacturing cost is reduced, but the number of drop generators that can be energized is limited
Solution Approach 1:
The patent introduces a time dimension through sequential addressing of drop generators within primitives. By using address leads that can be dynamically switched to select different drop generators, the system achieves control over many more drop generators than the number of physical input pads, effectively resolving the contradiction between manufacturing cost and productivity
3Productivity
If more drop generators are placed on the printhead die to improve printing quality and speed, then printing performance is improved, but the number of input pads required increases
Solution Approach 1:
Multiple drop generators within each primitive share common power leads and address leads. This merging of control resources allows a high density of drop generators to be integrated on the printhead die without a proportional increase in input pads, resolving the contradiction between printing quality and device complexity
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 enables a higher number of drop generators to be energized with fewer input pads, improving printing quality and speed while reducing costs, by effectively managing data and address signals within the firing cell circuit.
Implementation Method 1
the electrical current is passed through a selected firing resistor to heat the ink in a corresponding selected vaporization chamber and eject the ink through a corresponding nozzle
Implementation Method 2
Each firing resistor is coupled in series with the power lead and the drain-source path of a corresponding field effect transistor (FET)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A fluid ejection device (22/40) includes a first fire line (110a-110n/214a-214f), a second fire line (110a-110n/214a-214f), data lines (108a-108m/208a-208h), latch circuitry (152,404/162/184,186), first drop generators (60), and second drop generators (60). The first fire line is adapted to conduct a first energy signal including first energy pulses and the second fire line is adapted to conduct a second energy signal including second energy pulses. The data lines are adapted to conduct data signals that represent an image and the latch circuitry is configured to latch the data signals to provide latched data signals based on at least one clock signal. The first drop generators are configured to respond to the first energy signal to eject fluid based on the latched data signals and the second drop generators are configured to respond to the second energy signal to eject fluid based on the latched data signals.