Piezoelectric Inkjet Nozzle Viscosity Control
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Solution Overview
Problem
Existing inkjet printing devices using piezoelectric techniques are not suitable for optimal deposition of varnishes with viscosities outside the medium to high range, specifically struggling with varnishes of lower viscosity.
Innovation Solution
An inkjet printing device equipped with a piezoelectric actuator connected to a device controlling and regulating the form of the electric wave for varnish expulsion, allowing for adjustment based on viscosity and composition, featuring a voltage signal with specific edges and plateaus, and optionally incorporating a heating resistor for viscosity control and UV or infrared lamps for drying, along with a system for correcting lateral deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a piezoelectric actuator is used with fixed excitation parameters, then medium to high viscosity varnishes (100-1000 centipoises) can be deposited, but low viscosity varnishes (around 10 centipoises) cannot be optimally ejected
Solution Approach 1:
The patent applies dynamics by making the piezoelectric actuator's excitation parameters variable rather than fixed. The duration and power of the excitation signal are dynamically adjusted based on the viscosity of the varnish being deposited, allowing the same actuator to optimally eject drops across a wide viscosity range from 10 to 1000 centipoises.
Solution Approach 2:
The patent implements parameter changes by modifying the excitation parameters (duration and power) of the piezoelectric actuator according to the viscosity characteristics of different varnishes. This allows the system to adapt its operating parameters to match the specific requirements of each varnish type, achieving consistent deposition quality across varying viscosities.
2Extent of automation
If conventional printing methods (Offset Flexography, Screen Printing) are used, then protective layers can be applied, but digital precision and personalization capabilities are limited
Solution Approach 1:
The patent replaces conventional mechanical printing systems (Offset Flexography, Screen Printing) with a digital inkjet system using piezoelectric actuators. This substitution enables precise digital control over varnish deposition, allowing for personalized patterns and selective area coating while maintaining manufacturing feasibility through computerized management of the printing parameters.
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
Enables precise and efficient deposition of varnishes with varying viscosities, from 10 to 1000 centipoises, ensuring optimal ejection and fixation on substrates, regardless of viscosity, while maintaining image quality and resistance to external aggressions.
Implementation Method 1
each of the nozzles being vibrated by a piezoelectric actuator so that the excitation of the actuator in duration and in power determines the size and shape of the drop of varnish
Implementation Method 2
at least one nozzle of the device incorporates a heating resistor connected to a control device the viscosity of the drop of varnish in the nozzle
Implementation Method 3
the printing device comprises at least one U.V. lamp downstream of the printing station deposition of the varnish which exhibits an emission in a wavelength adapted to the activation of at least one photoinitiator of the composition of the varnish
Implementation Method 4
the printing device comprises at least one infrared lamp positioned opposite the substrate and arranged upstream of the U.V. lamp to pre-dry and stretch the varnish deposited on the substrate
Data Source
AI summary
The present invention relates to a jet printing device for applying a varnish forming a coating on a substrate surface comprising at least input and output magazines, a means for moving the substrate between the different workstations, several nozzles housed in a print head, at least one of the nozzles being supplied by a reservoir containing varnish to be projected onto the substrate, each of the nozzles being vibrated by a piezoelectric actuator such that the excitation of the actuator in duration and power determines the size and shape of the varnish droplet, characterized in that the piezoelectric actuator of at least one nozzle is connected to a device for controlling and regulating the shape of the voltaic wave of expulsion of the varnish droplet from the nozzle as a function of the viscosity and/or composition of the varnish to be deposited.