Firing Signal Forwarding in Fluid Ejection Devices
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Solution Overview
Problem
Fluid ejection devices, such as printer ink cartridges, require preheating of ink before vaporization, but existing methods using two transistors consume significant integrated circuit area and are inefficient, with energy dissipation issues.
Innovation Solution
A pulse width modulated signal is used to switch a transistor, which supplies a precursor warming pulse followed by a dead time and then a firing pulse to a resistor, vaporizing the fluid without the need for a warming transistor, thereby optimizing area usage and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a warming transistor is used for preheating fluid before vaporization, then the fluid can be preheated effectively, but the integrated circuit area is significantly consumed
Solution Approach 1:
The warming function is extracted from the integrated circuit by removing the warming transistor. Instead, a separate warming element is used that can be controlled by the firing circuitry, thereby eliminating the need for dedicated warming transistor area on the integrated circuit while maintaining the preheating capability.
Solution Approach 2:
The firing transistor and circuitry are designed to perform dual functions: both vaporization firing and warming control. The same transistor and circuit components that control the vaporization process are also used to control the warming phase, allowing one component to serve multiple purposes and reducing overall circuit complexity and area.
2Temperature
If a warming transistor is used for preheating fluid, then preheating can be controlled independently, but energy efficiency deteriorates due to significant energy dissipation in the integrated circuit
Solution Approach 1:
The warming control function is extracted from the integrated circuit to a separate control mechanism. The warming element is controlled by the firing circuitry through pulse width modulation rather than a dedicated warming transistor, reducing energy loss in the integrated circuit components.
Solution Approach 2:
The warming is achieved through periodic pulse width modulated signals rather than continuous current. The firing transistor switches current in controlled pulses to the warming element, allowing the fluid to be heated efficiently while minimizing energy dissipation in the circuit components through duty cycle control.
3Adaptability or versatility
If two transistors are used for warming and firing, then both preheating and vaporization functions are available, but the device complexity increases
Solution Approach 1:
The firing transistor is designed to perform both warming and vaporization functions. By using pulse width modulation and timing control, the same transistor serves dual purposes, eliminating the need for a separate warming transistor and reducing integrated circuit complexity while maintaining full functionality.
Solution Approach 2:
The warming and firing control functions are merged into a single control circuitry that uses pulse width modulated signals. The same transistor and control logic that manage vaporization are also used to manage the warming phase, combining multiple functions into unified hardware and software control.
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 approach reduces the area dedicated to preheating on the integrated circuit, improves energy efficiency, and enhances the consistency and reliability of fluid ejection, allowing for simpler control systems and improved print quality.
Implementation Method 1
a second firing transistor formed on the integrated circuit switches a firing current to the resistor. The firing current causes the resistive element to vaporize the fluid
Implementation Method 2
a first transistor formed on the integrated circuit switches a 'trickle' current. The current causes the resistor or the first warming transistor to pre-heat but not vaporize fluid in a chamber
Data Source
AI summary
A fluid ejection device has a nozzle group with a plurality of nozzle circuits and a fire controller in electronic communication with the plurality of nozzle circuits. The fire controller includes a fire data input for receiving fire data, a warm data input for receiving warm data, and a firing signal input for receiving a firing signal having a firing pulse preceded by a warming pulse. The fire controller is operable to conditionally modify the firing signal according to a state of warm data received via the warm data input and a state of fire data received via the fire data input. The fire controller is operable to forward the conditionally modified firing signal to one of the plurality of nozzle circuits to pass a current representative of the conditionally modified firing signal through a firing element of the particular nozzle circuit. Conditionally modifying the firing signal comprises either not modifying the firing signal, blocking the firing pulse and not blocking the warming pulse or blocking the firing pulse and the warming pulse.