Concave Support Rollers Suppress Wrinkles in Ink Discharge Range

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing printing technologies face challenges in suppressing the formation of wrinkles in the range where ink is discharged during the conveying of a printing medium, particularly in roll-to-roll methods, as prior solutions do not adequately address this issue.

Innovation Solution

The use of upstream and downstream rollers with concave-shaped peripheral surfaces that increase in diameter from the center towards the ends, combined with strategically positioned discharge heads and ink receivers, helps to suppress wrinkles by ensuring even ink distribution and contact with the printing medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional roller with uniform diameter is used to convey the printing medium, then the conveying process is simple, but wrinkles form in the ink discharge range

Engineering Contradiction:
Improvesuppression of wrinkle formationVSAvoidroller structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The roller is designed with a concave peripheral surface where the diameter increases from the center toward the ends in the axial direction. This curved geometry creates differential contact pressure across the printing medium width, with higher pressure at the edges and lower pressure at the center, effectively suppressing wrinkle formation in the ink discharge range while maintaining a relatively simple roller structure

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the printing medium is conveyed at high speed, then productivity increases, but wrinkle formation becomes more severe

Engineering Contradiction:
Improveconveying speedVSAvoidsurface smoothness of printing medium
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The concave roller geometry provides continuous contact pressure distribution that stabilizes the printing medium during high-speed conveying. The increased diameter at the ends provides greater contact area and pressure at the edges where wrinkles typically form first, allowing high-speed operation without compromising surface smoothness

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Area of stationary object

If ink is discharged to the entire width of the printing medium, then printing coverage is maximized, but wrinkles form in the discharge range

Engineering Contradiction:
Improveink discharge areaVSAvoidsuppression of wrinkle formation
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The roller applies different contact pressures to different regions of the printing medium. The concave shape creates higher contact pressure at the lateral ends and lower pressure at the center, providing localized wrinkle suppression exactly where needed in the ink discharge range while allowing full-width ink discharge

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3459750B1Printing apparatus and printing method
Publication Date: 2022.06.01 SCREEN HOLDINGS CO LTD
  • EP3459750B1 patent drawingFigure 1
  • EP3459750B1 patent drawingFigure 2~3
  • EP3459750B1 patent drawingFigure 4

AI summary

The ink is discharged to the printing medium F located in the first range R1 from the upstream end Wuu of the upstream winding part Wu where the support roller 26a and the printing medium F are in contact to the downstream end Wdd of the downstream winding part Wd where the support roller 26e and the printing medium F are in contact. The support rollers 26a, 26e located on both ends of the first range R1 are in contact with the printing medium F on the peripheral surfaces 261 having such a concave shape to increase the diameter from the center toward the ends in the width direction Y (axial direction). This causes these support rollers 26a, 26e to suppress the formation of wrinkles in the first range R1 where the ink is discharged.