CIJ Printer Column Segmentation for Speed and Quality
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Solution Overview
Problem
Continuous Ink Jet (CIJ) printers face a challenge in optimizing printing speed without degrading the quality of printed characters or codes, particularly for 2-dimensional codes and graphical codes, due to strong electrostatic interactions between charged drops, which limits the reduction of guard drops needed for faster printing.
Innovation Solution
Implementing a method that uses two sets of charge data databases for odd and even columns, allowing only every two positions to be printed in each column, with a reduced number of drops generated for each column, and adjusting the number of lines and columns to adapt to the available surface, thereby minimizing electrostatic interactions and improving printing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of guard drops is reduced to increase printing speed, then printing speed is improved, but print quality degrades due to strong electrostatic interactions between charged drops
Solution Approach 1:
The invention segments the column into super-imposed patterns where only every two positions are printed in each column. This segmentation reduces the density of charged drops, thereby reducing electrostatic interactions while maintaining print quality. The segmenting idea is applied by selectively printing only certain positions (every two positions) rather than all positions in a column.
Solution Approach 2:
The invention uses multiple super-imposed patterns (first pattern, second pattern, third pattern) that are combined to form the final print. This multi-dimensional approach allows the system to achieve high print quality through pattern superposition while maintaining low drop density in each individual pattern, thus reducing electrostatic interactions.
2Manufacturing precision
If guard drops are added between charged drops to reduce electrostatic interactions, then print quality is maintained, but printing speed decreases due to increased number of drops per column
Solution Approach 1:
Instead of adding guard drops between all charged drops, the invention segments the printing by printing only every two positions in each column. This natural segmentation inherently provides spacing between charged drops without requiring additional guard drops, thus maintaining print quality while improving printing speed.
Solution Approach 2:
The invention extracts and removes the need for guard drops by using a different approach - selective positioning of charged drops every two positions. This eliminates the harmful element (guard drops that slow down printing) while maintaining the beneficial effect (reduced electrostatic interactions through spacing).
3Manufacturing precision
If every position in each column is printed to achieve complete coverage, then print quality is maintained, but the number of electrostatic interactions increases due to higher drop density
Solution Approach 1:
The invention segments the column positions into printable and non-printable positions, printing only every two positions. This segmentation reduces drop density and consequently reduces electrostatic interactions between charged drops, while the super-imposed patterns ensure complete coverage and maintain print quality.
Solution Approach 2:
The invention applies different printing strategies to different positions within the column. Instead of uniform printing at all positions, it selectively prints only at specific positions (every two positions) in each column, creating local variations in drop density that reduce electrostatic interactions while maintaining overall print quality through pattern superposition.
4Device complexity
If the printing method is simplified to print all columns independently in dot matrix mode, then device complexity is reduced, but printing speed is limited by the need to process each column sequentially with maximum drops
Solution Approach 1:
The invention segments the column into multiple patterns (first, second, third patterns) that can be processed independently and then super-imposed. This segmentation allows for more efficient processing compared to traditional dot matrix mode, as each pattern can be optimized separately and processed in parallel or pre-planned, thereby improving printing speed without significantly increasing device complexity.
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 enhances printing speed while maintaining print quality by reducing the number of guard drops and electrostatic interactions, allowing for flexible adaptation to different surface sizes and shapes, such as those found on non-flat objects like cables or bottles.
Implementation Method 1
charged drops repel each other due to electrostatic interactions. The electrostatic forces being inversely proportional to the square of the distance between the drops
Data Source
Figure 1A~2
Figure 3A~3B
Figure 4A~4B
AI summary
The invention concerns a method for printing a graphical code on a surface (800), said graphical code having H lines and a W columns i (i=1,...W), and comprising a pattern of HxW cells, each cell being at the intersection of a column and of a line, each printed cell or dot being formed with help of a drop generated by a printhead of a continuous inkjet printer, two successive dots of a same column being separated by at least one non printed cell, said method comprising, for printing each column: * retrieving or selecting the charges to be applied to each of the drops for printing the dots of said column from at least one set of data or database (DB) of charges of the drops for each of a number of configurations of drops to be printed in a column, said number being equal to or less than 2(H/2)+1 if H is an even number or equal to or less than 2((H+1)/2)+1 if H is an odd number; * charging the drops for printing the dots of said column according to said charges retrieved or selected from said at least one set of data or database (DB) and printing said column.