Firing Pulse Circuit Control for Inkjet Printers
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Solution Overview
Problem
Printing apparatuses face challenges in controlling the transition speed of signals to ink actuators, leading to excess energy buildup, potential damage from back EMF, and variability in performance due to temperature changes, which affects high-resolution and high-speed printing.
Innovation Solution
A circuit is designed to control the current dissipation in ink actuators by managing the edges of firing pulses, using standard-sized components to ensure the current reaches zero within a controlled timeframe, preventing damaging voltages and maintaining consistent performance across a range of temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the current flow to the heater is turned off rapidly, then excess energy buildup is prevented, but back EMF voltages appear that can damage circuit components
Solution Approach 1:
A discharge path is provided in advance for the current flowing through the heater. When the firing pulse ends, the current can immediately transition to the discharge path through a diode, preventing both excess energy buildup and back EMF damage. The discharge path is prepared beforehand and activated automatically when needed.
Solution Approach 2:
A diode is introduced as an intermediary component between the heater and the power supply. The diode allows current to flow in one direction during the firing pulse and provides a controlled discharge path when the pulse ends, mediating the transition and preventing harmful back EMF voltages while dissipating excess energy.
2Productivity
If smaller ink actuators and nozzles are used, then higher resolution and print speeds are achieved, but the components become more sensitive to energy and require precise control of signal transition speeds
Solution Approach 1:
The circuit automatically manages its own current dissipation through the diode and discharge path. The system self-regulates the current flow and transition speeds without requiring external intervention or complex control mechanisms, ensuring reliable operation even with sensitive smaller actuators.
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
The solution allows for precise control of ink ejection, preventing excess energy buildup and back EMF damage, while maintaining high-resolution and high-speed printing capabilities with minimal temperature-induced variability in the dissipation time.
Implementation Method 1
signals are supplied that cause the heaters to heat the ink held in a chamber at the nozzles which in turn causes the ink to be ejected from the nozzles
Implementation Method 2
rapid changes in that current and/or in the firing pulse that causes that current can cause excess voltages to appear in the system, due to inductances of the circuitry and components
Data Source
AI summary
A printing apparatus is provided that precisely control the transition of an electrical signal that causes a printing substance to be deposited. In particular, in some embodiments, a circuit is configured to control the application of a firing pulse to a printing element, and the printing element is configured to control the application of a printing substance. The circuit in this embodiment is configured to condition or control the transition of the firing pulse from the first state to the second state such that current through the printing element dissipates to zero over a period of time that is neither too fast nor too slow.