Image Forming Apparatus Nip Pressure Gradient
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Solution Overview
Problem
Existing image forming methods using roller-shaped or belt-shaped liquid absorbing members often result in smeared images or incomplete liquid removal due to increased fluid resistance and image disturbance, especially when the liquid absorbing member is pressed against the ink receiving medium.
Innovation Solution
The image forming apparatus and method involve a porous body with a specific nip pressure profile, where the pressure peak at the inlet side is lower than at the outlet side, allowing for effective liquid absorption without disturbing the image, by adjusting the nip pressure ratio and using a multilayer porous body structure to enhance absorption and prevent image disturbance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a liquid absorbing member is pressed against the ink receiving medium to remove liquid component, then liquid removal efficiency is improved, but image disturbance such as smearing occurs
Solution Approach 1:
The patent applies dynamic pressure control by varying the nip pressure along the contact length between the liquid absorbing member and ink receiving medium. The pressure is highest at the inlet side and decreases toward the outlet side, creating a pressure gradient that optimizes both liquid absorption and image protection. This dynamic pressure distribution allows the system to achieve effective liquid removal while preventing image smearing.
Solution Approach 2:
The patent changes the pressure parameter spatially along the nip part to resolve the contradiction. By establishing a pressure gradient where P1/X1 < P2/X2 (pressure peak near inlet divided by distance from inlet is less than pressure peak near outlet divided by distance from outlet), the system optimizes the balance between liquid absorption efficiency and image quality preservation.
2Productivity
If high pressure is applied to enhance liquid absorption, then absorption rate is improved, but fluid resistance increases causing image disturbance
Solution Approach 1:
The patent implements dynamic pressure adjustment where the nip pressure is not uniform but varies along the contact length. High pressure is applied at the inlet side to maximize absorption rate, while pressure gradually decreases toward the outlet side to reduce fluid resistance. This dynamic approach allows the system to maintain high productivity while minimizing harmful fluid resistance effects.
Solution Approach 2:
The pressure application follows a periodic-like pattern with pressure peaks positioned strategically at different locations along the nip part. The pressure distribution creates alternating zones of high absorption and low resistance, optimizing the overall absorption process while preventing image disturbance.
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 enables high absorption and removal of the liquid component from the image without causing image disturbance, ensuring effective liquid removal and improved image quality by reducing fluid resistance and maintaining image integrity during the absorption process.
Implementation Method 1
a liquid absorbing member that includes a porous body having a first surface and absorbing at least a portion of the first liquid from the first image
Implementation Method 2
the liquid component is absorbed and removed from an ink image by contacting a roller-shaped porous body with the ink image
Data Source
AI summary
In a process of an ink receiving medium entering a nip part with a liquid absorbing member, force in a direction to sweep up an image to be processed as an absorption removal treatment target is reduced by changing a nip pressure of the nip part in a conveying direction of the ink receiving medium. Furthermore, when peeling off the liquid absorbing member from the ink receiving medium from the nip part, force for pulling a liquid component toward a porous body is effectively applied. As a result, it is possible to achieve high absorption and removal of the liquid component from the image to be processed while suppressing disturbance of the image to be processed.