Pressing Device with Dual Biasing for Embossed Paper Transfer
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face challenges in transferring toner images onto recording media with coarse surfaces, such as embossed papers, due to inadequate toner transfer at recessed portions, resulting in patterns of light and dark patches in the output image.
Innovation Solution
An improved pressing device is introduced, comprising a pressing member, lateral plates, and an adjuster, which allows for adjustable biasing forces to be applied to a nip forming member, enabling precise control of nip pressure at the secondary transfer nip to enhance toner transfer onto recording media with varying surface textures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a biasing member with a relatively large biasing force is used to increase the nip pressure at the secondary transfer nip, then the transferability onto coarse surfaces is improved, but the pressing member needs to be stronger and more complex to accommodate the large biasing force
Solution Approach 1:
The pressing device is divided into two independent pressing members: a first pressing member that applies a first biasing force, and a second pressing member that applies a second biasing force. This segmentation allows each pressing member to be optimized independently, so the first pressing member does not need to accommodate the full large biasing force alone, reducing its structural complexity while maintaining high nip pressure for improved transferability onto coarse surfaces.
Solution Approach 2:
The system changes the parameter of biasing force by using two different biasing forces (first biasing force and second biasing force) instead of a single large biasing force. The second pressing member provides an additional biasing force that can be adjusted independently, allowing the first pressing member to be designed with lower strength requirements while the combined effect achieves the necessary high nip pressure for reliable transfer onto coarse surfaces.
2Device complexity
If a single pressing member is used to apply biasing force to the nip forming member, then the device structure is simpler, but the ability to dynamically adjust nip pressure for different surface textures is reduced
Solution Approach 1:
The system introduces dynamic adjustability by providing a second pressing member that can independently adjust the second biasing force. This allows the nip pressure to be dynamically modified according to different recording medium surface textures, enhancing adaptability while keeping each individual pressing member relatively simple in structure.
Solution Approach 2:
By segmenting the pressing function into two independent pressing members, the system achieves both simplicity and adaptability. Each pressing member can be designed with a relatively simple structure, but their combined and independently adjustable forces provide the versatility needed to handle different surface textures effectively.
3Reliability
If a relatively large biasing force is applied to ensure adequate nip pressure for coarse surfaces, then transfer uniformity is improved, but the pressing member structure becomes more complex and robust
Solution Approach 1:
The pressing function is segmented into two independent pressing members, each applying a portion of the total required biasing force. This segmentation allows the first pressing member to be designed with lower strength requirements, as it only needs to accommodate the first biasing force, while the second pressing member provides additional force. The combined effect maintains the high nip pressure needed for uniform transfer onto coarse surfaces without requiring either individual member to be excessively strong.
Solution Approach 2:
The system changes the parameter approach by using two different biasing force parameters (first biasing force and second biasing force) instead of a single large biasing force parameter. This allows the first pressing member to be optimized for lower strength while the second pressing member supplements the total force, achieving the required transfer uniformity without excessive strength requirements for individual components.
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 solution ensures improved toner transferability on both smooth and coarse surfaces, reducing image defects like light and dark patches by dynamically adjusting the nip pressure, thereby achieving consistent image density and quality.
Implementation Method 1
the biasing member presses the pressing member against the intermediate transfer belt, thereby enabling the secondary transfer roller supported by the pressing member to contact the intermediate transfer belt
Implementation Method 2
the surface of the intermediate transfer belt including the elastic layer can deform and thus fit the embossed surface of the recording medium
Implementation Method 3
a secondary transfer electric field is formed between the secondary-transfer opposing roller and the secondary transfer roller so that the toner image moves electrostatically from the secondary-transfer opposing roller side to the secondary transfer roller side
Data Source
AI summary
A pressing device includes a pressing member, a first lateral plate including a first connecting portion to support a first end of the pressing member, a second lateral plate including a second connecting portion to support a second end of the pressing member opposite to the first end, a first adjuster connected to the first lateral plate at the first connecting portion and to the second lateral plate at the second connecting portion, and a biasing member. The biasing member biases at least one of the first lateral plate, the second lateral plate, and the first adjuster to press the pressing member against the target in a pressing direction. The first adjuster is connected to the first lateral plate and the second lateral plate such that a relative position of the second connecting portion relative to the first connecting portion is changeable in the pressing direction.