Feeding Device Dual Suction Sheet Separation
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Solution Overview
Problem
Conventional feeding devices in image forming apparatuses face issues with double feeding due to sheet materials adhering to each other, especially under high humidity conditions, leading to inaccurate separation and feeding, which affects the quality of the printing process.
Innovation Solution
The feeding device incorporates a lower suction unit with a suction force smaller than the upper surface suction unit but stronger than the adhesion between sheets, ensuring that only the top sheet is sucked onto the conveying member, preventing overlapping and double feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single suction unit with strong suction force is used to reliably pick up the top sheet, then the top sheet can be securely attached to the conveying member, but multiple sheets may be sucked together causing double feeding
Solution Approach 1:
The suction unit is divided into multiple independent suction elements arranged in an array. Each suction element has its own suction force control, allowing selective activation. The array is segmented into different zones (first array and second array) with different suction force characteristics, enabling precise control over which sheets are picked up based on their position in the stack.
Solution Approach 2:
Different suction elements within the array have different suction force characteristics. The first array provides stronger suction force for reliably picking up the top sheet, while the second array provides weaker suction force that is insufficient to overcome sheet adhesion. This local differentiation of suction quality prevents double feeding while ensuring reliable top sheet pickup.
2Reliability
If strong suction force is applied to separate adhered sheets, then sheets can be separated even under high humidity conditions, but the conveying member may damage the sheet material
Solution Approach 1:
The suction force applied to each sheet is dynamic and differentiated. The first array applies stronger suction force dynamically to separate adhered sheets, while the second array applies weaker suction force that does not damage the sheet. This dynamic differentiation allows effective separation under high humidity without causing sheet damage.
Solution Approach 2:
The multiple suction elements act as intermediaries between the conveying member and the sheet stack. By distributing the suction force across multiple elements with different strengths, the system mediates between the need for strong separation force and the need to protect sheet integrity, achieving both goals simultaneously.
3Manufacturing precision
If multiple suction elements are used to prevent double feeding, then sheet separation accuracy improves, but the device complexity increases
Solution Approach 1:
The array of suction elements serves multiple functions simultaneously: it picks up sheets from the stack, separates adhered sheets through differential suction forces, and controls the number of sheets picked up by activating specific elements. This multi-functionality reduces the need for additional separate mechanisms, thereby limiting the increase in device complexity.
Solution Approach 2:
The system controls suction force parameters by selectively activating different suction elements in the array. By changing which elements are active and at what suction force levels, the system achieves precise separation control without requiring complex mechanical structures. Parameter control replaces structural complexity.
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 configuration reliably prevents double feeding by effectively separating sheets, even under adverse conditions, thereby improving the accuracy and quality of the sheet feeding process.
Implementation Method 1
an upper surface suction unit that sucks a top sheet material which is positioned at the top of sheet materials stacked in the sheet material housing by generating negative pressure
Implementation Method 2
a lower suction unit that exerts a suction force, which is directed downward, on the sheet materials that are stacked in the sheet material housing and positioned near the top sheet material
Data Source
AI summary
A feeding device includes: a sheet material housing configured to allow a plurality of sheet materials to be stacked; an upper surface suction unit that sucks a top sheet material by generating negative pressure at a position facing the upper surface of the top sheet material; a sheet material conveying unit that causes the top sheet material, which is sucked up, to be sucked onto a conveying member and conveys the top sheet material; and a lower suction unit that exerts a suction force downward onto the sheet materials that are positioned near the top sheet material, wherein a suction force exerted on the top sheet material downward by suction of the lower suction unit is smaller than a suction force exerted on the top sheet material upward by suction of the upper surface suction unit and is larger than adhesion between the sheet materials.