Developing Device Agitator Mixing Toner and Carrier
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Solution Overview
Problem
In two-component developing methods for electrophotographic image forming, insufficient toner charging leads to scattering and background contamination due to inadequate mixing and agitation of toner and carrier, affecting image quality and apparatus cleanliness.
Innovation Solution
A developing device with a developing frame and agitator that mixes and delivers toner and carrier in a direction parallel to the developing roller, utilizing a combination of helical blades and paddles, along with concave portions on the bottom surface, to enhance mixing efficiency and charging of the toner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the toner and carrier are simply mixed without enhanced agitation, then the device structure remains simple, but the mixing and charging efficiency is insufficient leading to toner scattering and background contamination
Solution Approach 1:
The developing device is segmented into multiple functional zones: a developing zone where toner is transferred to the photosensitive body, and a separate agitating zone with concave portions where intensive mixing occurs. This segmentation allows complex mixing functions to be isolated from the simple developing function, improving reliability without overly complicating the overall device structure.
Solution Approach 2:
Concave portions are formed on the bottom surface of the developing frame to create curved surfaces that enhance the agitation of toner and carrier. The curved geometry promotes better mixing by creating varied flow patterns and increasing contact between particles, thereby improving charging efficiency and preventing toner scattering.
2Reliability
If the toner charging time is increased to improve charging sufficiency, then the mixing and charging efficiency improves, but the developing speed and productivity may be reduced
Solution Approach 1:
The agitator performs periodic agitation cycles within the developing device, creating alternating periods of intensive mixing and steady-state developing. This periodic action ensures sufficient toner charging during agitation phases while maintaining continuous image formation during developing phases, thus balancing reliability and productivity.
Solution Approach 2:
Toner and carrier are preliminarily mixed and charged in the agitating zone with concave portions before entering the developing zone. This preliminary charging action ensures that toner is adequately charged prior to the developing process, preventing scattering and background contamination without requiring extended charging time during the actual developing operation, thereby maintaining high productivity.
3Object-generated harmful factors
If conventional mixing methods are used, then the device structure remains simple, but toner scatters and causes background contamination
Solution Approach 1:
Concave portions are formed on the bottom surface of the developing frame to create curved surfaces that enhance the agitation of toner and carrier. The curved geometry promotes better mixing by creating varied flow patterns and increasing contact between particles, thereby improving charging efficiency and preventing toner scattering.
Solution Approach 2:
The carrier acts as an intermediary that facilitates toner charging through friction during agitation in the concave portions. The carrier particles mediate the charging process by providing frictional contact to the toner, preventing direct toner-to-toner scattering and background contamination while enabling sufficient charging.
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 effectively increases the mixing and charging time of toner and carrier, reducing the risk of image quality degradation and background contamination, ensuring stable image formation and extended developer performance.
Implementation Method 1
a toner and a carrier are mixed and charged by friction
Implementation Method 2
The carrier is attached to a developing roller by a magnetic force
Implementation Method 3
The toner is separated from the carrier due to a developing bias voltage applied between the developing roller and the photosensitive body
Data Source
AI summary
Provided is a developing device configured to develop an electrostatic latent image formed on an image bearing member by feeding a toner to the electrostatic latent image. The developing device includes a developing frame configured to form an inner space in which the toner and a carrier are to be mixed, a developing roller including an outer periphery to which the developer attaches where the developing roller feeds the toner included in the developer to the image bearing member. The developing device includes an agitator installed in the inner space and configured to mix and deliver the toner and the carrier in a direction parallel to an axial direction of the developing roller, and a plurality of concave portions arranged on a bottom surface of the developing frame.