Digital Printing Waveform Control for Variable Drop Size
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current digital printing technologies face challenges in achieving high-quality, high-speed printing with long-term stability and low resolution without the need for printing plates, requiring high nozzle density and small drop sizes, which complicates mechanical alignment and increases production costs and waste.
Innovation Solution
A method for a digital printing system where a single waveform for ink drop control signals is stored, allowing for varying drop sizes by selectively suppressing segments of the waveform, enabling precise control of drop size and speed through a control apparatus with a switched output, using a piezo element as the activator to manage ink chamber volume and drop formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high nozzle density and small drop sizes are used to achieve high printing speed and quality, then printing speed and quality are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies parameter changes by varying the duration of the control signal waveform to produce different drop sizes from the same nozzle. By suppressing segments of the waveform, the system generates multiple drop sizes (e.g., 1 pl, 2 pl, 4 pl) without requiring different nozzle densities, thus maintaining high printing quality and speed while reducing device complexity
Solution Approach 2:
The system uses dynamic control of the waveform segments to adaptively produce different drop sizes based on printing requirements. The control apparatus dynamically suppresses or transfers different portions of the stored waveform to the activator, enabling flexible drop size variation that maintains printing productivity without increasing nozzle density
2Manufacturing precision
If high nozzle density is used to achieve high printing quality, then printing quality is improved, but manufacturing precision requirements increase
Solution Approach 1:
By changing the control signal waveform parameters (duration, segment suppression), the system produces varied drop sizes from coarser nozzles, achieving offset-printing-like quality without the need for high-precision mechanical alignment of dense nozzles
Solution Approach 2:
A single nozzle performs multiple functions by producing different drop sizes through waveform control, replacing the need for multiple precisely aligned nozzles with different functions, thus reducing manufacturing precision requirements
3Adaptability or versatility
If multiple waveforms are stored for different drop sizes, then drop size control flexibility is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple drop size control functions into a single stored waveform by using segment suppression. Instead of storing separate waveforms for different drop sizes, the system stores one waveform and selectively suppresses segments to achieve variable drop sizes, reducing control signal storage complexity
Solution Approach 2:
The single stored waveform is segmented into suppressible portions, allowing flexible combination of segments to produce different effective waveforms for different drop sizes. This segmentation provides adaptability while maintaining a compact single-waveform storage structure
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 allows for the generation of drops with varying sizes and speeds, maintaining precision and flexibility, reducing the complexity and cost of print head manufacturing, and enabling high-quality printing with lower nozzle resolution and speed, comparable to offset printing.
Implementation Method 1
each printing system has a nozzle, at least one ink chamber and an activator, e.g. a piezoelectric activator, which is associated with the at least one ink chamber, for the discharge of ink drops from the ink chamber in question via the nozzle in question onto a substrate to be printed on, as a response to a control signal
Data Source
AI summary
The invention relates to a printing method for a digital printing device, comprising a print head having a plurality of printing systems and comprising at least one control apparatus for feeding control signals to the printing systems for the production of ink drops. Each printing system has a nozzle, at least one ink chamber and an activator, e.g. a piezoelectric activator, which is associated with the at least one ink chamber, for the discharge of ink drops from the ink chamber in question via the nozzle in question onto a substrate to be printed on, as a response to a control signal. In the control apparatus, only a single waveform for the control signal having a specified time curve is stored for ink drops of all sizes, comprising, for example, optionally an initial waiting time, a first edge, followed by a first holding time, and, after the first holding time, a second, opposite edge, optionally followed by a second holding time. The size and/or speed of ink drops is varied by virtue of the fact that, at most for a single, intrinsic drop size, the entire stored waveform is transferred as a control signal to the activator in question, while for all other, effective drop sizes, only part of the common, stored waveform is transferred to the activator in question, namely one or more selected portions, while one or more other portions of the stored, common waveform are not supplied to the activator in question in the control signal.