Transport Belt Thickness Gradient for Paper Wrinkle Prevention
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Solution Overview
Problem
Wrinkles in paper movement during printing can cause damage to print heads and paper jams, especially in page wide array printers with static arrays of inkjet print heads, due to uneven transport belt speeds and thicknesses.
Innovation Solution
The use of transport belts with varying thicknesses and speeds, where faster belts are positioned on the outside and slower belts on the inside, combined with a vacuum hold-down system to maintain media flatness and tension, avoids wrinkles by stretching the medium at the input and compressing it at the print zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transport belts of uniform thickness are used, then manufacturing is simpler, but wrinkles occur due to speed variations
Solution Approach 1:
The patent applies local quality by varying the thickness of different transport belts to create a speed profile. Outer transport belts are made thicker than inner belts, causing them to move faster and compensate for the natural speed decrease toward the center. This localized thickness variation resolves the contradiction by maintaining paper flatness without requiring all belts to have identical, tightly controlled dimensions.
Solution Approach 2:
The patent changes the physical parameter of transport belt thickness to control belt speed. By adjusting the thickness parameter of each belt, the system creates a deliberate speed gradient that prevents paper wrinkles. This parameter change approach allows manufacturing with relaxed tolerances while achieving the desired kinematic effect.
2Manufacturing precision
If tight tolerances are applied to transport belt thickness, then paper movement is more uniform, but manufacturing costs increase
Solution Approach 1:
Instead of requiring uniform thickness across all belts with tight tolerances, the patent applies local quality by intentionally making outer belts thicker than inner belts. This deliberate non-uniformity creates the desired speed profile while allowing each belt to be manufactured with relaxed, cost-effective tolerances.
Solution Approach 2:
The patent inverts the conventional approach by not seeking uniformity but instead deliberately creating controlled non-uniformity. Rather than making all belts the same thickness with tight tolerances, the system makes outer belts intentionally thicker to compensate for the natural speed decrease toward the center, achieving uniform paper transport through non-uniform belt construction.
3Device complexity
If all transport belts move at the same speed, then the system is simpler to control, but paper wrinkles due to natural speed gradient
Solution Approach 1:
The patent applies local quality by varying the thickness of different transport belts to create a speed profile. Outer transport belts are made thicker than inner belts, causing them to move faster and compensate for the natural speed decrease toward the center. This localized thickness variation resolves the contradiction by maintaining paper flatness without requiring complex active speed control systems.
Solution Approach 2:
The patent replaces a complex mechanical speed control system with a passive geometric solution. Instead of using motors, sensors, and control algorithms to actively adjust each belt's speed, the system uses differential belt thickness to passively create the desired speed gradient. This substitution of mechanics with geometry simplifies the control system while achieving the same effect.
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 approach effectively prevents wrinkles and paper jams, ensuring smooth paper movement and maintaining print quality without the need for tight tolerances in transport belt manufacturing, thus reducing costs.
Implementation Method 1
a vacuum hold-down system to maintain media flatness and tension
Data Source
AI summary
An apparatus includes a plurality of transport elements to cause a movement of a medium received at a media input in a movement direction towards a media output, wherein the plurality of transport elements are arranged spaced apart from each other in the direction transverse to the movement direction of the medium, wherein the plurality of transport elements include a first transport element to be moved with a first velocity, a second transport element to be moved with a second velocity, and a third transport element to be moved with a third velocity, the second transport element arranged between the first and third transport elements, and wherein the first and third velocities are greater than the second velocity.