Inkjet Head Control for Margin-less Printing Side Staining
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Solution Overview
Problem
Inkjet printing technologies face challenges in margin-less printing, where the inertial force causes ink to be printed not only on the surface but also on the thickness part (sides) of base materials, leading to poor finish and user dissatisfaction.
Innovation Solution
The method involves controlling the inkjet head to stop discharging ink when moving from the outside to the inside of the base material and discharge ink when moving from the inside to the outside, using divided image data to prevent printing on the side surfaces, and employing a gradation discharge section to maintain consistent discharge rates, thereby preventing side surface staining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inkjet head discharges ink while moving from the outside of the base material toward the end during margin-less printing, then the printing coverage is maximized, but ink is printed on the thickness part (side) of the base material due to inertial force, causing poor finish
Solution Approach 1:
The patent divides the image data into multiple sections corresponding to different positions on the base material (front surface, side surface, back surface). By segmenting the printing process into direction-dependent stages, the system selectively discharges ink only on the front surface when moving from outside toward the end, and only on the back surface when moving from inside toward the end, thereby preventing unwanted ink deposition on the side surfaces while maintaining comprehensive printing coverage.
Solution Approach 2:
The patent applies different printing strategies depending on the moving direction of the inkjet head. When moving from outside toward the end, ink is discharged only on the front surface. When moving from inside toward the end (return stroke), ink is discharged only on the back surface. This directional inversion approach ensures that ink is never discharged during passages that would cause staining on the side surfaces, thus resolving the contradiction between coverage and quality.
2Productivity
If the inkjet head moves rapidly to achieve margin-less printing, then productivity increases, but inertial force causes ink to be deposited on the thickness part of the base material
Solution Approach 1:
The patent performs preliminary processing of the image data to determine which regions should receive ink based on the inkjet head's moving direction. Before actual printing, the system identifies front surface regions for discharge during outward movement and back surface regions for discharge during return movement. This preliminary segmentation allows the system to maintain high printing speeds while preventing inertial force from causing unwanted deposition on side surfaces.
Solution Approach 2:
The patent acknowledges that inertial force cannot be eliminated during rapid printing movements, but converts this potentially harmful effect into a beneficial control mechanism. By deliberately designing the printing strategy to account for inertial force direction, the system uses the natural physics of ink discharge to its advantage - allowing ink to be deposited only on surfaces where inertial force will carry it appropriately (front surface during outward movement, back surface during return movement), while avoiding areas where it would cause defects (side surfaces).
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 effectively prevents side surface staining and maintains printing quality by ensuring ink is only applied where intended, even with nozzle clogging, and achieves a fine finish without reducing discharge rates.
Implementation Method 1
an inkjet head that discharges ink
Implementation Method 2
As the inertial force acts on the ink, printing is performed not only on the surface but also on the thickness part (side) of the base material
Data Source
Figure 1
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Figure 4
AI summary
An inkjet printing machine (1) includes controlling means (5) and performs margin-less printing on a base material (15) on the basis of image data having a size larger than that of the base material (15) by discharging ink from an inkjet head (22) while relatively moving the base material (15) and the inkjet head (22) for one cycle of reciprocation or more in a main-scanning direction. On the basis of the image data, the controlling means (5) controls the inkjet head (22) to stop discharging ink, when the inkjet head (22) is moved from the outside toward an end of the base material (15). The controlling means (5) controls, when the inkjet head (22) is moved from the inside toward the end of the base material (15), the inkjet head (22) to discharge ink to complement an image in a section where the inkjet head (22) stops discharging ink.