Tandem Printer Vacuum Zones for Waste-Free Media Loading
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Solution Overview
Problem
Large format hybrid printers face inefficiencies in tandem printing due to media waste when loading a second roll while a first roll is already loaded, as both rolls are transported at the same speed by a single belt, leading to media waste on the already loaded roll.
Innovation Solution
Implementing a method with independent vacuum zones on the transport belt to allow the already loaded print medium to remain stationary while the new medium is transported, using a smaller negative pressure to enable the belt to slip past the stationary medium and a larger pressure to adhere the new medium, thereby reducing waste and simplifying the loading process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transport belt is used to transport both rolls in parallel, then the printer structure is simplified, but media waste occurs on the already loaded roll when loading a new roll
Solution Approach 1:
The transport belt is divided into multiple independent vacuum zones (first vacuum zone, second vacuum zone, etc.) that can be controlled independently. Each vacuum zone can apply or release vacuum pressure separately, allowing selective adhesion of different media rolls to different segments of the belt. This segmentation enables the belt to transport one media roll while leaving another stationary, preventing media waste.
Solution Approach 2:
Different vacuum zones on the transport belt have different vacuum pressure states at different times. When loading a new media roll, the vacuum zone corresponding to the new roll is activated while the vacuum zone corresponding to the already loaded roll is deactivated. This local differentiation in vacuum application allows selective media adhesion and prevents unwanted media transport and waste.
2Productivity
If both rolls are transported at the same speed by the single belt, then the printing process is simplified, but loading a second roll causes media waste on the first roll
Solution Approach 1:
The vacuum pressure applied to different zones of the transport belt is made dynamic and time-dependent. During normal tandem printing, both vacuum zones are activated to transport both media rolls at the same speed. During media loading, the vacuum pressure is dynamically adjusted: the zone with the already loaded media is deactivated while the zone for the new media is activated. This dynamic control enables waste-free media loading while maintaining productive tandem printing capability.
Solution Approach 2:
The vacuum zones are activated and deactivated in periodic cycles corresponding to media loading requirements. When media needs to be loaded, the system periodically switches the vacuum state of specific zones, allowing new media to be transported while previously loaded media remains stationary. This periodic activation/deactivation pattern enables continuous productivity with minimal waste.
3Reliability
If negative pressure is applied to transport media from input to output side, then media is kept flat during printing, but loading a new roll while one is loaded causes media waste
Solution Approach 1:
The vacuum system is segmented into multiple independent zones along the transport belt. Each zone can apply or release vacuum pressure independently. When loading new media, only the vacuum zone corresponding to the new media is activated to keep it flat during transport, while the vacuum zone for the already loaded media is deactivated, allowing that media to remain stationary without waste.
Solution Approach 2:
Different segments of the transport belt have different vacuum pressure applications based on local needs. The local vacuum zone for the newly loaded media applies negative pressure to maintain flatness during transport, while the local vacuum zone for the already loaded media releases pressure to prevent unwanted movement and waste. This local differentiation resolves the contradiction between maintaining media flatness and preventing waste.
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
The method reduces print medium waste and simplifies the loading process by allowing the already loaded medium to remain stationary while the new medium is loaded, ensuring continuous printing without media waste.
Implementation Method 1
a negative pressure can be applied in the suction chamber assembly to draw a print medium against the transport belt
Implementation Method 2
The frictional holding force between the transport belt and the already loaded print medium is proportional to the normal force on the said print medium
Data Source
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AI summary
A method for a printer comprising a transport device comprising an endless transport belt supported on a pair of support rollers, which between them define a medium support plane, over which medium support plane a print station is provided, wherein printer is configured to transport print media from an input station by the transport belt in a dual configuration at the same speed to an output station perpendicular to a scanning direction of the print station on the medium support plane, and wherein a plurality of vacuum zones beneath the transport belt comprises a first vacuum zone which is beneath and extends over a first part of the medium support plane over which first print media is intended to be transported to the output station, and a second vacuum zone which is beneath and extends over a second part of the medium support plane over which second print media is intended to be transported to the output station, wherein the second vacuum zone is adjacent to the first vacuum zone in the scanning direction, and the method comprises the steps of independently in time turning off the first or second vacuum zone in order to stop delivering a vacuum pressure to the corresponding part of the medium support plane for enabling a load of the corresponding print media in the printer and/or a positioning of the corresponding print media on the medium support plane, and independently in time turning on the first or second vacuum zone in order to deliver a vacuum pressure to the corresponding part of the medium support plane for enabling a transport of the corresponding print media over the corresponding part of the medium support plane.