Inkjet Printer Conveyance Control for Multipass Image Quality
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Solution Overview
Problem
Inkjet printing methods using a conveyance roller can result in image degradation due to friction between the pinch roller and the print medium, leading to conveyance errors and ink landing position deviations during multipass printing.
Innovation Solution
An inkjet printing apparatus with a conveyance unit using paired rollers to convey the print medium in alternating directions, ensuring the print region remains downstream of the rollers to avoid contact with the pinch roller, and a control unit that alternates print conveyance operations to maintain precise ink application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pinch roller contacts the print medium during reciprocal conveyance, then the print medium can be conveyed in both directions, but friction force changes causing conveyance errors and image degradation
Solution Approach 1:
The conveyance process is segmented into two distinct phases: a first conveyance direction where the pinch roller contacts the print medium, and a second conveyance direction where the pinch roller is separated from the print medium. This segmentation allows the system to maintain conveyance functionality while eliminating the harmful friction contact during the return stroke, thereby preserving ink landing position accuracy.
Solution Approach 2:
The pinch roller's contact state with the print medium is dynamically changed based on the conveyance direction. During the first conveyance direction, the pinch roller is in contact to provide friction for movement. During the second conveyance direction, the pinch roller is separated to eliminate friction. This dynamic adjustment resolves the contradiction by adapting the contact state to the operational requirements of each phase.
2Measurement precision
If the conveyance roller is arranged close to the print unit, then conveyance accuracy is improved, but the pinch roller may contact the ink-applied region causing image degradation
Solution Approach 1:
The system dynamically controls the pinch roller's contact state with the print medium based on its position relative to the print unit. When the pinch roller approaches the print unit during conveyance, it is separated from the print medium to prevent contact with the ink-applied region. This dynamic control allows the conveyance roller to be positioned close to the print unit for accuracy while eliminating the harmful friction contact that would cause image degradation.
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 suppresses image degradation and conveyance errors, ensuring accurate ink placement and maintaining image quality during multipass printing.
Implementation Method 1
two roller members of a conveyance roller and a pinch roller pinch the print medium and convey the print medium by being rotated
Implementation Method 2
a print head that is provided downstream of the paired conveyance rollers in the first direction and that prints an image by ejecting ink to the print medium
Data Source
AI summary
An object is to provide a full-line inkjet printing apparatus and a printing method that can suppress occurrence of image degradation in the case where a conveyance roller conveys a print medium and multipass printing is performed. The maximum conveyance amount in a return route is set to be smaller than a distance between the conveyance roller and a print head.