Magnetic Drive Developer Roller Jitter Suppression
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Solution Overview
Problem
Conventional printers experience irregular developments on electrostatic latent images due to periodic deviations in the circumferential speed of the developing roller, leading to impaired image quality with irregular pitches or jitters in printed images.
Innovation Solution
An image forming unit with a developer carrier having an elastic layer, where the thickness of the elastic layer is set between 0.5 mm to 2.5 mm, and the circumferential speed ratio with respect to the image carrier is maintained between 1.10 to 1.45, or the developer carrier is rotated with a remaining toner rate between 20% to 40% on its surface, to prevent image quality deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the developing roller is driven by a conventional drive mechanism with gears and couplings, then the structure is simple and easy to manufacture, but the circumferential speed of the developing roller deviates periodically causing image quality deterioration
Solution Approach 1:
The patent replaces the conventional mechanical drive mechanism (gears, couplings) with a magnetic drive system. The developing roller is equipped with a magnetic layer that interacts with a drive magnet, eliminating the need for mechanical transmission components. This substitution removes the source of periodic speed deviations while maintaining simple overall structure.
Solution Approach 2:
The patent changes the drive method from mechanical contact to magnetic field interaction. By using a magnetic layer with specific properties (thickness 0.5-5.0mm, permeability 1.0-5.0μm) on the developing roller, the drive system achieves precise circumferential speed control without mechanical complexity.
2Strength
If the elastic layer thickness is increased to improve durability, then the developer carrier becomes more robust, but the circumferential speed control becomes less precise leading to greater jitter
Solution Approach 1:
The patent establishes specific parameter ranges for the elastic layer (thickness 0.5-5.0mm, permeability 1.0-5.0μm) that balance durability and precision. These optimized parameters allow the magnetic field to effectively transmit rotational speed while the elastic layer provides sufficient mechanical strength and shock absorption.
Solution Approach 2:
The developing roller uses a composite structure combining an elastic layer with a magnetic layer. The elastic layer provides mechanical strength and durability, while the magnetic layer (with controlled thickness and permeability) enables precise magnetic drive control, achieving both robustness and precision simultaneously.
3Productivity
If the circumferential speed ratio is increased to improve development efficiency, then the development speed increases, but irregular developments occur causing jitters in printed images
Solution Approach 1:
By replacing the mechanical gear-driven system with a magnetic drive system, the patent achieves smooth and precise control of the circumferential speed ratio. The magnetic field interaction eliminates mechanical backlash and periodic deviations, allowing the speed ratio to be optimized for efficiency without compromising image uniformity.
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 effectively suppresses jitter occurrences in printed images, ensuring improved image quality by stabilizing the development process and maintaining the durability of the photosensitive drum.
Implementation Method 1
a magnetic layer having a thickness in a range from 0.5 mm to 5.0 mm and having a permeability in a range from 1.0 μm to 5.0 μm; and a drive magnet, wherein the magnetic layer and the drive magnet are arranged to attract each other
Data Source
AI summary
An image forming unit suppressing occurrences of jitters, includes an image carrier rotating by drive force transmitted via a first route to form an electrostatic latent image, and a developer carrier having an elastic layer carrying a developer on a surface thereof and rotating by drive force transmitted via a second route to develop the electrostatic latent image. The electrostatic latent image is developed with the developer under a development condition that, with the elastic layer of a thickness from 0.5 mm to 2.5 mm, the developer carrier is rotated with a circumferential speed ratio to the image carrier in a range from 1.10 to 1.45, or that, with the elastic layer of a thickness more than 2.5 mm but not more than 5.0 mm, the developer carrier is rotated with a circumferential speed ratio to the image carrier in a range from 1.10 to 1.24.