Developing Device Toner Carrier Coating and Airflow Management
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Solution Overview
Problem
High-speed rotation in developing devices leads to positive internal pressure, causing toner leakage and accumulation, which disrupts the toner layer on the photosensitive drum and results in defects like 'dropping toner' due to scattered toner floating near the developing roller-magnetic roller opposing portion.
Innovation Solution
A developing device with a toner carrier having a coat layer formed by dipping in a resin coating liquid, where the lower end during dipping is positioned upstream in the airflow direction, and air outlet ports along the developing container's wall communicate with a duct to manage airflow and prevent toner leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the toner carrier is dipped into the resin coating liquid with one end first to form a coat layer, then the coat layer thickness becomes non-uniform (thicker at the lower end), but this creates airflow imbalance that worsens toner leakage control
Solution Approach 1:
The patent intentionally creates an asymmetric coat layer thickness distribution on the toner carrier by dipping it into the resin coating liquid with one end first. The coat layer is made thicker at the lower end (upstream side in airflow direction) and thinner at the upper end (downstream side). This asymmetric structure is designed to balance the airflow distribution across the developing device, preventing turbulent flow and reducing toner leakage through the opening.
2Object-generated harmful factors
If air outlet ports are formed in the developing container wall to manage airflow, then toner leakage is reduced, but the device structure becomes more complex
Solution Approach 1:
The developing container wall is segmented by forming multiple air outlet ports at different positions along the longitudinal direction. These ports divide the airflow control function into multiple discrete locations, allowing precise management of air flow patterns. The ports are arranged to create balanced airflow that prevents toner leakage while maintaining a relatively simple overall structure.
3Object-generated harmful factors
If the lower end of the toner carrier during dipping is positioned upstream in the airflow direction, then airflow balance is improved and toner leakage is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The toner carrier is pre-oriented in a specific position before being dipped into the resin coating liquid. The lower end (which will be the upstream side in the airflow direction) is positioned first during dipping. This preliminary positioning ensures that the coat layer forms with the correct asymmetric thickness distribution, balancing the airflow and preventing toner leakage. The orientation is established before the coating process begins, making the subsequent manufacturing steps more straightforward.
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 uniform airflow and reduces toner leakage and accumulation, maintaining a stable toner layer on the photosensitive drum, thereby minimizing defects and improving the developing device's performance.
Implementation Method 1
The coat layer is formed by means of a dipping method of dipping the toner carrier into a resin coating liquid
Data Source
AI summary
A developing device includes a developing container, a toner carrier, and a plurality of air outlet ports. The plurality of air outlet ports are formed in such part of a wall of the developing container as faces the toner carrier, along a longitudinal direction of the developing container, the air outlet ports communicating with a duct next to the developing container. The toner carrier includes a coat layer on the outer circumferential surface thereof. The coat layer is formed by dripping the toner carrier into a resin coating liquid with one end in the longitudinal direction thereof first, the one end being a lower end of during the dipping, and then lifting the toner carrier out of the resin coating liquid. The toner carrier is arranged such that the lower end of during the dipping is disposed on an upstream side with respect to an airflow direction in the duct.