Postprocessing Tray Air Layering for Wet Sheet Alignment
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Solution Overview
Problem
Existing postprocessing devices face challenges in efficiently stacking and aligning sheets due to friction and instability caused by contact between sheets, particularly when sheets are in a wet state from inkjet printing, leading to reduced productivity.
Innovation Solution
A postprocessing device with a fan that forms an air layer between the upper face of stacked sheets and the lower face of newly placed sheets by emitting air in the transport direction, minimizing friction and maintaining sheet alignment through controlled air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sheets are stacked directly on the processing tray without air layer, then stacking is simple, but friction between sheets causes misalignment and reduces productivity
Solution Approach 1:
The patent introduces air as an intermediary substance between stacked sheets to reduce friction. The air layer acts as a mediator that prevents direct contact between sheet surfaces, allowing sheets to be stacked at high speed without misalignment caused by friction between wet sheets.
Solution Approach 2:
The patent uses pneumatic principles by emitting air flow between sheets during stacking. The air flow is controlled to maintain an air layer that reduces friction while allowing rapid stacking, combining the benefits of high-speed stacking with precise alignment maintenance.
2Manufacturing precision
If air layer is formed between sheets, then friction is reduced and alignment is maintained, but device complexity increases due to fan and air emission system
Solution Approach 1:
The patent employs a fan that utilizes the natural air flow and pressure differential created during the stacking process itself. The system serves itself by using the stacking motion to generate the air flow conditions needed, rather than requiring complex external air supply systems.
Solution Approach 2:
The patent changes the physical parameters of the air emission system by controlling air flow rate, pressure, and direction dynamically during stacking. This allows the same simple fan structure to adapt to different stacking conditions and maintain optimal air layer thickness without complex mechanical adjustments.
3Productivity
If sheets are in wet state from inkjet printing, then productivity is reduced due to increased friction, but air layer formation requires additional energy consumption
Solution Approach 1:
The patent applies partial air flow only where and when needed during the stacking process. Rather than continuously emitting air, the fan operates intermittently or locally at critical stacking moments, providing just enough air layer formation to prevent friction-related misalignment while minimizing energy consumption.
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 air layer reduces friction and maintains sheet alignment, enhancing productivity by ensuring proper stacking and reducing sheet displacement, even when sheets are wet or less rigid.
Implementation Method 1
The fan forms an air layer between an upper face of sheets already stacked on the stacking surface of the processing tray and a lower face of a sheet newly placed on the processing tray, by emitting air in a transport direction of the sheet
Data Source
AI summary
A postprocessing device is attached to an image forming apparatus. The postprocessing device includes a processing tray, a sheet processor, and a fan. The processing tray is for stacking thereon sheets on which an image has been formed and which is transported from the image forming apparatus. The sheet processor performs predetermined postprocessing on the sheets stacked on the processing tray. The fan forms an air layer between an upper face of the sheets already stacked on the stacking surface of the processing tray and a lower face of a sheet newly placed on the processing tray, by emitting air in a transport direction of the sheet, from an upstream side in the transport direction toward the stacking surface.