Serial Printing Transport Units for Variable Media Thickness
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Solution Overview
Problem
Existing serial printing devices face reduced throughput due to the inability to adjust the height of the central conveyor belt relative to the print head for print media with varying thicknesses, especially when using print heads with longitudinal elongation, such as inkjet or laser heads, which limits the transport speed and efficiency of feeding and discharging print media.
Innovation Solution
A device with independent first and second transport units that can move orthogonally relative to the print head, allowing for real-time adjustment of the positioning of the upstream transport unit based on the thickness of subsequent print media, enabling transfer within the printing area and increasing throughput by allowing faster feeding and discharge of print media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single height-adjustable conveyor belt is used to feed print media to the print head, then the distance between the print medium and print head can be adjusted for different thicknesses, but the conveyor belt cannot be varied in height during printing, causing subsequent print media to wait and reducing throughput
Solution Approach 1:
The single conveyor belt system is segmented into two independent conveyor belts (first and second conveyor belts). The first conveyor belt feeds print media to the transfer area, while the second conveyor belt receives printed media. This segmentation allows independent height adjustment of each belt, enabling the first belt to be positioned for the next print medium while the second belt maintains printing position, thus eliminating waiting time and increasing throughput.
Solution Approach 2:
The first conveyor belt can be adjusted to the appropriate height position in advance for the next print medium while the current print medium is still being printed. This preliminary positioning action eliminates the waiting time that would otherwise occur between printing operations, allowing continuous high-speed operation.
2Reliability
If the central conveyor belt is kept at a fixed height during printing, then the print medium maintains a suitable distance from the print head, but subsequent print media cannot be transferred to the central conveyor belt until printing is complete, reducing transport speed
Solution Approach 1:
The printing system is segmented into two independent conveyor belt systems operating in parallel. The first conveyor belt operates independently to feed the next print medium, while the second conveyor belt maintains the current print medium in the printing position. This independence allows the feeding speed to exceed the printing speed without compromising printing quality, thus increasing overall transport speed and throughput.
Solution Approach 2:
The transfer area acts as an intermediary zone where print media is transferred from the first conveyor belt to the second conveyor belt. This intermediary mechanism allows continuous feeding from the first belt while maintaining stable printing on the second belt, decoupling the feeding speed from the printing speed constraint.
3Device complexity
If a single conveyor belt system is used, then the structure is simpler, but the transport device cannot feed and discharge print media simultaneously at high speed, limiting throughput
Solution Approach 1:
The conveyor system is segmented into two independent belts: the first conveyor belt dedicated to feeding print media and the second conveyor belt dedicated to discharging printed media. This segmentation enables simultaneous high-speed feeding and discharging operations, doubling the effective throughput compared to a single belt system while maintaining manageable structural complexity through modular design.
Solution Approach 2:
Each conveyor belt is designed to perform multiple functions: the first conveyor belt feeds print media to the transfer area and can be adjusted for different media thicknesses, while the second conveyor belt receives printed media and transports it away. Both belts share the same structural design and control mechanism, reducing overall system complexity while achieving high throughput.
Data Source
AI summary
A device for serial printing of print media, particularly mailpieces, with a print head having a planar printing face and a printing area extending longitudinally, and with a transport device for feeding print media to be printed to the print head. The transport device includes first and second transport units, which move the print media parallel to the printing face and can be moved in an orthogonal direction relative to the printing face in order to guide a print medium on the transport units to the printing face of the print head and at a distance away from the printing face that is suitable for printing. The first and second transport units can be moved independently of one another and a transfer area of the printing face is provided to transfer a print medium from the first to the second transport unit.