Inkjet Head Drive Unit Meniscus Oscillation Control
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Solution Overview
Problem
Inkjet printers face issues with increased viscosity of ink in nozzles when the inkjet head is outside the image forming region, leading to discharge failures, as the meniscus oscillation signal cannot be applied without a print timing signal, and forced discharge methods are inefficient without a print timing signal.
Innovation Solution
A head drive unit that generates a meniscus oscillation signal or a flushing signal independently of the print timing signal by using a drive signal selection unit to switch between discharge and oscillation signals based on positional information, ensuring continuous ink flow and preventing viscosity increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the meniscus oscillation signal is applied in synchronization with the print timing signal, then the viscosity increase of ink is prevented during printing, but the meniscus oscillation signal cannot be input when the inkjet head is outside the image forming region
Solution Approach 1:
The patent segments the control signal generation into two independent parts: the print timing signal from the print control apparatus and the meniscus oscillation signal from the head drive apparatus. This segmentation allows the meniscus oscillation signal to be generated and applied independently of the print timing signal, enabling it to be input even when the inkjet head is outside the image forming region where no print timing signal is available.
Solution Approach 2:
The head drive apparatus generates the meniscus oscillation signal autonomously based on its own detection of the inkjet head's presence outside the image forming region, without requiring external control from the print control apparatus. This self-service mechanism ensures continuous meniscus oscillation and prevents viscosity increase during idle periods.
2Reliability
If dummy image data is added to the end of image data, then the meniscus oscillation signal can be applied outside the image forming region, but the transfer rate is lowered and print throughput is decreased
Solution Approach 1:
The patent extracts the meniscus oscillation function from the image data processing flow. Instead of relying on dummy image data to trigger meniscus oscillation during idle periods, the system directly generates and applies the meniscus oscillation signal based on positional information, completely removing the need for dummy data and its associated throughput penalty.
Solution Approach 2:
The head drive apparatus proactively generates the meniscus oscillation signal as soon as it detects that the inkjet head is outside the image forming region, before any potential viscosity increase occurs. This preliminary action eliminates the need for reactive dummy data insertion and maintains continuous ink flow stability without interrupting the normal printing workflow.
3Reliability
If the print control apparatus generates the meniscus oscillation signal, then the signal can be applied continuously, but additional processing power is required which increases system complexity
Solution Approach 1:
The head drive apparatus performs the self-service function of autonomously generating and applying the meniscus oscillation signal based on its own detection capabilities. This transfers the processing burden from the print control apparatus to the head drive apparatus, maintaining continuous signal application without adding complexity to the central control system.
Solution Approach 2:
The meniscus oscillation signal generation is localized to the head drive apparatus, which is positioned close to the inkjet head and has direct access to positional information. This local implementation reduces the need for complex inter-apparatus communication and control signal routing, simplifying the overall system architecture.
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 effective prevention of ink viscosity increases and stable discharge even when the inkjet head is outside the image forming region, without requiring additional processing power or complex circuit changes, thus maintaining print throughput and reducing costs.
Implementation Method 1
Each inkjet head has a piezoelectric element that expands or contracts in response to an applied voltage
Implementation Method 2
a meniscus oscillation signal used for oscillating a liquid surface at a nozzle tip
Data Source
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AI summary
An object is to provide a head drive unit that enables preventing an increase in viscosity of inks in nozzles even when a head is present outside an image forming region and also provide an inkjet printer, and the head drive unit includes: a drive signal output device 31 that outputs either a discharge signal or a meniscus oscillation signal to each head; a cycle generator 326 that generates a cyclic oscillation timing signal for the meniscus oscillation signal; an input interruption detector 324 that detects that input of a print timing signal is interrupted by monitoring the input of the print timing signal; and a drive signal selector 32 that selects the meniscus oscillation signal as a drive signal output from the drive signal output device and continuously applies the meniscus oscillation signal to all nozzles of each head in synchronization with an oscillation timing signal when interruption of the input of the print timing signal is detected.