Variable Pressure Developing Rollers for Color Image Quality
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Solution Overview
Problem
Conventional color printers experience degraded image quality due to uniform pressure forces applied in image forming units, leading to differences in toner mixture ratios and external additive distribution, resulting in OPC filming and voids in color images.
Innovation Solution
Implementing a mechanism to adjust the pressure forces between developing rollers and photoconductive drums in each image forming unit, with varying pressures to match the specific toner characteristics and external additive proportions for black, yellow, magenta, and cyan toners, ensuring optimal toner adhesion and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same pressure force is applied in all image forming units, then the device structure is simple and easy to manufacture, but the image quality is degraded due to differences in toner characteristics and external additive distribution
Solution Approach 1:
The patent applies different pressure forces to different image forming units based on their specific toner characteristics and external additive proportions. Each image forming unit is customized with optimal pressure settings tailored to its local requirements, resolving the contradiction between structural simplicity and image quality by allowing localized optimization without complex overall restructuring.
Solution Approach 2:
The patent changes the pressure force parameter for each image forming unit according to the toner mixture ratio and external additive distribution. By adjusting this physical parameter locally, the system achieves optimal image quality for each unit while maintaining relative simplicity in the overall device architecture.
2Productivity
If higher pressure force is applied to ensure proper toner adhesion, then toner transfer efficiency is improved, but OPC filming and background fog increase, degrading image quality
Solution Approach 1:
The patent optimizes the pressure force parameter to achieve the minimum effective pressure required for proper toner adhesion without exceeding the threshold that causes OPC filming and background fog. This precise parameter control resolves the contradiction between transfer efficiency and harmful effects.
Solution Approach 2:
Different image forming units are assigned different pressure forces based on their specific toner characteristics and external additive proportions. This localized optimization ensures each unit operates at its optimal pressure point, achieving efficient toner transfer while preventing harmful effects specific to each toner formulation.
3Productivity
If higher pressure force is applied to improve toner adhesion, then toner transfer is enhanced, but the lifespan of photoconductive drums and cleaning blades is reduced
Solution Approach 1:
The patent adjusts the pressure force parameter to the minimum effective level required for proper toner adhesion and transfer. By optimizing this parameter, the system achieves sufficient toner transfer quality while minimizing mechanical stress on photoconductive drums and cleaning blades, thereby extending their operational lifespan.
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 adjustment improves image quality by reducing OPC filming and background fog, maintaining toner charging characteristics, and extending the lifespan of photoconductive drums and cleaning blades, while preventing voids in color images.
Implementation Method 1
the surface of a photoconductive drum is charged by a charging roller, then is exposed to light from an LED head to form an electrostatic latent image. A thin layer of toner formed on a developing roller electrostatically adheres to the electrostatic latent image on the photoconductive drum
Data Source
AI summary
Various methods, devices and techniques for improving image quality for an image forming device are disclosed. For example, improved image quality can be had for an image forming apparatus having a first image forming unit including a first image carrier and a first developer carrier in contact with the first image carrier at a first pressure, and the first image carrier carries a first developer having a first charging characteristic, and a second image forming unit including a second image carrier, and a second developer carrier in contact with the second image carrier at a second pressure, greater than the first pressure, and the second developer carrier carries a second developer having a second charging characteristic. The first pressure and the second pressure are preset based on the first charging characteristic and the second charging characteristic.