Roll-to-roll printing splice detection and meandering correction
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Solution Overview
Problem
In roll-to-roll printing, the splice portion between sheets can cause issues with meandering correction, leading to paper waste due to improper sensing by sheet end position sensors, especially when sheet widths change before and after the splice portion.
Innovation Solution
A printing apparatus equipped with a splice detection unit, a conveyance unit, and a meandering correction unit that includes a sensor to detect sheet ends and correct meandering based on the relationship between the splice position and sensor detection area, allowing for precise control and adjustment to prevent paper waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the splice portion is detected and the sheet is fed forward to take up the splice portion, then the splice portion can be prevented from entering the printing area, but paper waste occurs because printing cannot be performed on areas before and after the splice portion
Solution Approach 1:
The patent replaces the mechanical sheet feeding approach with a head position adjustment mechanism. Instead of physically moving the sheet to avoid the splice portion, the system adjusts the print head position based on the measured shift amount, allowing printing to continue on both sides of the splice portion without paper waste.
Solution Approach 2:
The patent changes the control parameter from sheet position to head position. By measuring the shift amount of the succeeding sheet and adjusting the head position accordingly, the system maintains print quality while eliminating the need to waste paper around splice portions.
2Loss of substance
If the head position is adjusted according to the measured shift amount to maintain print position, then paper waste is reduced, but meandering correction cannot be properly performed when sheet width changes before and after the splice portion
Solution Approach 1:
The patent segments the sheet into preceding and succeeding portions with different widths, and applies different correction strategies to each. The meandering correction unit is controlled to perform correction only on sections with consistent width, while excluding the splice portion area, thereby maintaining both paper utilization and correction precision.
Solution Approach 2:
The patent applies local quality control by enabling meandering correction only in regions where the sheet width is consistent, and disabling it in the splice portion region where width changes occur. This localized approach maintains printing precision without being hindered by the splice portion.
3Object-affected harmful factors
If printing is performed after feeding the sheet forward until the splice portion is taken up, then the splice portion does not enter the printing area, but printing cannot be performed on areas before and after the splice portion
Solution Approach 1:
The patent replaces the mechanical solution of feeding the sheet forward with a control system solution. The head position is adjusted based on the detected splice portion position and measured shift amount, allowing printing to continue efficiently without physically moving the sheet past the splice portion.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the splice portion position, measuring the shift amount of the succeeding sheet, and adjusting the head position accordingly. This feedback mechanism allows printing to proceed without interruption while avoiding the splice portion, maintaining both printing quality and productivity.
Data Source
AI summary
A printing apparatus that prints on a sheet supplied from a rolled sheet and takes up the sheet in a roll shape, includes: a splice detection unit configured to detect a splice portion of the sheet, a conveyance unit configured to convey the sheet, a meandering correction unit including a sensor unit configured to detect a sheet end portion of the sheet in a width direction of the sheet on a downstream side of the splice detection unit and configured to correct meandering of the sheet based on detection of the sheet end portion by the sensor unit, and a control unit configured to control the meandering correction unit based on a relationship between a position of the splice portion and a detection area of the sensor unit.