Duplex Printer Criss-Cross Media Loop for High-Speed Printing
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Solution Overview
Problem
Conventional duplex inkjet printers suffer from reduced printing speed, complex media feed paths, paper jams, and noise due to the need for reversing drive motors and complex mechanisms, making them less efficient and more prone to errors compared to simplex printing.
Innovation Solution
A duplex printing system using a single printhead with a 'loop-the-loop' media feed path and unidirectional drive rollers, eliminating the need for reversing motors and maintaining a minimal printer footprint by positioning the output tray above the input tray, with idler rollers positioned above and below the drive rollers to counteract engagement forces and reduce radial loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional duplexing mechanisms are used with reversing drive motors, then duplex printing capability is achieved, but printing speed is reduced to about half of simplex printing speed
Solution Approach 1:
Instead of reversing the paper direction or printhead movement to achieve duplex printing, the invention inverts the approach by maintaining unidirectional motion and using a looped media path that returns paper to the printhead from the opposite side. The media feed mechanism continuously feeds paper in one direction through a looped path, eliminating the need for reversing motors while maintaining high printing speed.
Solution Approach 2:
The invention implements continuous unidirectional media feeding through a looped path, ensuring the drive motor operates continuously in one direction without stopping or reversing. This continuous action maintains constant printing speed while achieving duplex output, as paper is fed through the loop and presented to the printhead repeatedly in the same directional flow.
2Adaptability or versatility
If conventional duplexers use complex media feed paths with reversing mechanisms, then duplex printing is enabled, but the system becomes prone to paper jams and generates noise
Solution Approach 1:
The invention inverts the conventional approach by eliminating reversing mechanisms entirely. Instead of complex paths with directional changes, it uses a simple looped path with continuous unidirectional feeding, dramatically reducing paper jam risks and mechanical noise while maintaining duplex functionality.
Solution Approach 2:
The invention extracts and removes the reversing drive motor and complex directional control mechanisms from the system. By taking out these problematic components and replacing them with a simple looped path and unidirectional feeder, the system achieves duplex printing without paper jams or noise.
3Productivity
If duplex printing requires two printheads, then high-speed duplex printing is achieved, but printer cost and complexity increase
Solution Approach 1:
The invention makes a single printhead perform the function of two printheads by implementing a looped media path. The same printhead prints on both sides of the paper as the paper is fed through the loop and presented to the printhead repeatedly, eliminating the need for duplicate printheads while maintaining high printing speed.
Solution Approach 2:
The looped media path is pre-configured to present the paper in the correct orientation and position for the printhead to print on the opposite side during the return pass. This preliminary arrangement of the media path ensures that one printhead can efficiently perform duplex printing without requiring additional printheads.
4Area of stationary object
If duplex printers use C-chute configurations, then compact footprint is achieved, but output tray positioning above input tray creates space constraints
Solution Approach 1:
The invention resolves the tray positioning conflict by utilizing the vertical dimension and looped path geometry. The media path loops back underneath the printhead and input tray area, allowing the output tray to be positioned above the input tray without creating conflicts, as the looped path routes media through the available vertical and horizontal spaces efficiently.
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
Enables high-speed duplex printing without speed reduction, reduces the risk of paper jams, and simplifies the feed mechanism, maintaining a compact printer design while ensuring smooth operation and reduced noise.
Implementation Method 1
a first drive roller positioned at a first side of the printhead, the first drive roller being engaged with first and second idler rollers
Implementation Method 2
a second drive roller positioned at a second side of the printhead, the second drive roller being engaged with third and fourth idler rollers
Implementation Method 3
the first idler roller is positioned below the first drive roller and the second idler roller is positioned above the first drive roller... the idler rollers positioned above and below the drive rollers to counteract engagement forces and reduce radial loads
Data Source
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AI summary
A printer includes: a stationary inkjet printhead (2); a media feed path (3) for guiding print media twice past the printhead (2); and a feed mechanism for feeding print media unidirectionally through the media feed path (3) at a constant speed. The media feed path (3) includes: a first section (3a) configured for feeding print media past the printhead (2) from a first side of the printhead in a first direction with respect to the printhead (2); a second section (3b) downstream of the first section (3a), the second section (3b) being configured for guiding print media around a single loop, the loop being positioned at a second side of the printhead (2) opposite the first side; and a third section (3c) downstream of the second section (3b), the third section (3c) being configured for feeding print media past the printhead (2) from the second side of the printhead (2) in an opposite second direction with respect to the printhead (2).