Inkjet Line Printing with Layered Segments and Drying Gaps
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Solution Overview
Problem
Inkjet printing methods struggle to produce thin, uniform, and visually appealing lines due to the semicircular shape of the last printed droplet causing a pumping pressure that results in line widening and unevenness, necessitating impractical high printing speeds or leading to unclean results.
Innovation Solution
The method involves printing a line in multiple layers, with each layer forming a line segment, allowing for partial drying between layers to prevent medium flow, and overlapping or adjacent printing of droplets to maintain uniformity without increasing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple drops of printing medium are applied in succession to form a thin line, then line precision is improved, but line widening and unevenness occur due to pumping pressure from the semicircular droplet shape
Solution Approach 1:
The printing process is divided into multiple sequential print passes, where each pass deposits a segment of the line. By breaking the continuous line into discrete segments that are printed at different times, the pumping pressure effect is minimized because each segment has time to stabilize before the next is added.
Solution Approach 2:
The substrate surface is pre-treated to optimize wettability and contact angle before printing. This preliminary preparation ensures that the printing medium forms the desired shape with minimal pumping pressure and reduces the tendency for lateral flow, thereby maintaining line uniformity.
2Manufacturing precision
If printing speed is increased to prevent line widening, then line precision is improved, but print quality deteriorates due to unclean results and line breaks
Solution Approach 1:
The line is printed in multiple segments across different passes rather than attempting to print the entire line continuously at high speed. This allows each segment to be deposited and stabilized at moderate speeds, ensuring quality while maintaining overall efficiency.
Solution Approach 2:
The printing process uses periodic deposition of printing medium with controlled intervals between drops and passes. This rhythmic, controlled approach allows the medium to set properly between deposits, preventing defects while maintaining productive printing speed.
3Stability of the object's composition
If printing medium flow is allowed to occur, then line continuity is improved, but line width becomes non-uniform due to local widening
Solution Approach 1:
The line is constructed from multiple discrete segments printed in sequence. Each segment is deposited and allowed to stabilize before the next is added, creating continuity through controlled accumulation rather than through uncontrolled flow, thus maintaining uniform width.
Solution Approach 2:
The printing process controls parameters such as drop spacing, deposition rate, and drying time to optimize the balance between continuity and uniformity. By adjusting these parameters, the medium achieves sufficient flow for continuity without excessive flow that would cause widening.
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 the printing of thin, precise, and uniform lines without deviations or interruptions, improving optical and functional quality by ensuring continuous and smooth edges.
Implementation Method 1
the semicircular shape of the last printed droplet at the freshly printed end of the line creates a pumping pressure of the liquid printing medium within the line
Implementation Method 2
the printing medium of the first print layer is technically assisted to dry before a further print layer is printed
Data Source
Figure 1~4
AI summary
The invention relates to a method for printing at least one precise line (1) by means of inkjet printing. The aim of the invention is to provide a method for printing at least one precise line by means of inkjet printing, which method allows for the printing of a particularly thin, precise line which is uniform over the length and which has no deviation or irregularity in at least one spatial direction and no undesired interruptions. To achieve this aim, the method according to the invention provides for the following as method steps: first, providing a substrate to be printed on, and subsequently printing a first print layer onto the substrate surface, for which purpose at least one print head nozzle and the substrate surface are moved relative to each other along a nozzle path (2), the print head nozzle printing, in each case, a plurality of printing-medium drops (3) in immediate succession along the nozzle path to form a line portion (4), and subsequently leaving clear a printing gap (5) without printing medium on the substrate surface in order to reduce the flowing of printing medium along the line portion. Subsequently, the printing medium of the first print layer is surface-dried, and thereafter at least one additional print layer is printed by moving a print head nozzle and the substrate surface relative to each other along the nozzle path, more particularly the same nozzle path, the print head nozzle printing, in each case, a plurality of printing-medium drops in immediate succession to form an additional line portion (6); the additional line portion printed in the additional print layer being arranged immediately adjacent to or overlapping with an already surface-dried line portion which precedes and/or comes after along the nozzle path and which was printed in a prior print layer.