Inkjet Printhead Drive Circuit for Pulse Shaping and Lower Power Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inkjet printers face challenges in controlling the shape of voltage pulses for printhead capacitance, leading to inconsistent droplet uniformity and high power dissipation, which limits print frequency and duty cycle due to inefficient energy use and cooling requirements.
Innovation Solution
A drive circuit that uses a plurality of charging and discharging voltage pulses applied to an inductor to charge and discharge the printhead capacitance, allowing for control over the pulse shape and reducing power consumption by adjusting the total on-time and spacing of pulses based on the number of active nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single voltage pulse is applied directly to the printhead capacitance, then the charging process is simple and fast, but the pulse shape cannot be controlled and power dissipation is high
Solution Approach 1:
The single voltage pulse is segmented into multiple smaller voltage pulses applied to the inductor. This segmentation allows control over the charging process while reducing peak power dissipation. The inductor integrates these segmented pulses to produce a controlled single charge to the printhead capacitance.
Solution Approach 2:
Multiple periodic voltage pulses are applied to the inductor instead of a single continuous pulse. This periodic action enables control over the pulse shape delivered to the printhead while distributing the power dissipation over time, reducing instantaneous power loss.
2Manufacturing precision
If control over pulse shape is implemented, then droplet uniformity and print quality improve, but device complexity increases
Solution Approach 1:
An inductor is introduced as an intermediary component between the voltage source and the printhead capacitance. This inductor mediates the charging process by integrating multiple voltage pulses into a controlled single charge, enabling pulse shape control without requiring complex switching circuits directly at the printhead.
Solution Approach 2:
The circuit utilizes changes in inductor current and voltage over time to achieve pulse shape control. By controlling the timing and amplitude of multiple voltage pulses applied to the inductor, the resulting current waveform through the inductor can be shaped to produce consistent droplet ejection across varying capacitance conditions.
3Power
If large power supplies and heatsinks are used to handle power dissipation, then sufficient energy can be provided, but the system size and cooling requirements increase
Solution Approach 1:
The drive circuit uses dynamic switching of multiple voltage pulses to the inductor, allowing the system to deliver the required energy through time-varying current rather than requiring a continuously high-power supply. This dynamic approach reduces the peak power requirements and associated heat generation.
Solution Approach 2:
The inductor stores energy from multiple preliminary voltage pulses before delivering the final charge to the printhead capacitance. This preliminary energy storage in the inductor's magnetic field allows the system to accumulate energy gradually and release it in a controlled manner, reducing the need for large power supplies and heatsinks.
4Adaptability or versatility
If the printhead capacitance varies with the number of active nozzles, then the circuit must adapt to different loads, but maintaining consistent pulse shape becomes more difficult
Solution Approach 1:
The system incorporates detection of the number of active nozzles and uses this information to control the timing and amplitude of voltage pulses applied to the inductor. This feedback mechanism allows the drive circuit to adapt to varying printhead capacitance while maintaining consistent pulse shape through adjusted pulsing parameters.
Solution Approach 2:
The drive circuit changes parameters such as pulse width, amplitude, and timing intervals based on the detected number of active nozzles. By dynamically adjusting these parameters, the system maintains consistent pulse shape delivery to the printhead regardless of capacitance variations caused by different nozzle configurations.
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 enables stable pulse shaping for varying loads, reduces power consumption, and improves print quality by maintaining consistent ink ejection, while minimizing energy wastage and cooling needs.
Implementation Method 1
an inductor connected to a drive connection of the printhead to provide a charge path for current to charge the capacitance
Implementation Method 2
the printhead having a capacitance
Data Source
AI summary
A drive circuit for charging a printhead for ejecting drops of ink is provided, the printhead having a capacitance. The drive circuit comprises a power supply comprising a first connection and a second connection. An inductor is connected to the first connection of the power supply, wherein the inductor is connected to a first drive connection of the printhead to provide a charge path for current to charge the capacitance. The second connection of the power supply is connected to a second drive connection of the printhead. The drive circuit also comprises means for applying a plurality of charging voltage pulses to the inductor to provide a single charge of the capacitance for a single cycle of ink ejection from the printhead. A method of operating the drive circuit is also provided.