Developing Device Advance Impeding Member Toner Aggregation
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Solution Overview
Problem
In tandem image forming systems, the aggregation of toner between the supply roller and the opposing side wall of the first holding chamber leads to increased torque, uneven image density, and wear on the supply roller, due to the pressure and adhesion of toner particles, particularly with wax-containing toners that form strong aggregates.
Innovation Solution
A developing device configuration with a second holding chamber above the first, a communication opening between the two, and an advance impeding member positioned over the gap between the supply roller and the opposing side wall to prevent toner from entering and forming aggregates, thereby reducing pressure and adhesion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the second holding chamber is disposed above the first holding chamber to reduce horizontal space, then the apparatus size in horizontal direction is minimized, but toner aggregation occurs between the supply roller and opposing side wall leading to increased torque and uneven image density
Solution Approach 1:
The patent transitions from a horizontal arrangement of holding chambers to a vertical arrangement, utilizing the vertical dimension to reduce horizontal footprint. The second holding chamber is positioned above the first holding chamber, allowing toner to be supplied vertically to the supply roller while maintaining compact horizontal dimensions.
Solution Approach 2:
The patent introduces an advance impeding member with a specific surface configuration (inclined surface or protrusion) positioned at the critical gap region between the supply roller and opposing side wall. This localized structural modification prevents toner aggregation in the problematic area while maintaining overall system compactness.
2Volume of stationary object
If the gap between the supply roller and opposing side wall is reduced to minimize space, then device compactness is improved, but toner pressure and adhesion increase causing aggregation and supply roller wear
Solution Approach 1:
The advance impeding member is strategically positioned at the critical region where toner aggregation occurs (between the supply roller and opposing side wall). Its inclined surface or protrusion creates a localized barrier that redirects toner flow, preventing accumulation in the narrow gap while maintaining overall chamber compactness.
Solution Approach 2:
The advance impeding member acts as an intermediary element between the toner and the opposing side wall. It intercepts and redirects toner particles before they can enter the problematic gap region, mediating the interaction between toner flow and the confined space geometry.
3Quantity of substance
If toner is supplied in large quantity to the supply roller to ensure adequate developer availability, then developing capability is improved, but toner aggregation increases torque and causes uneven image density
Solution Approach 1:
The advance impeding member creates a localized control zone at the toner supply interface. By positioning the inclined surface or protrusion at the critical gap region, it prevents toner aggregation in the high-pressure zone between the supply roller and opposing side wall, allowing adequate toner quantity to be maintained without excessive aggregation forces.
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 minimizes the formation of aggregated blocks, reducing torque and image density unevenness, and extends the life of the supply roller by preventing toner adhesion and aggregation, while maintaining a compact device size.
Implementation Method 1
a communication opening provided between the two chambers for allowing the developer inside the second holding chamber to drop down into the first holding chamber
Implementation Method 2
the supply roller, which supports toner around its peripheral face, is rotated to supply the toner on the supply roller to a developing roller serving as a developer support member
Data Source
AI summary
A developing device is provided with which the increase in torque of a supply roller, unevenness of image density, and wear to the supply roller caused by the formation of an aggregated block of toner in the gap between the supply roller and the opposing side wall of a supply developer holding chamber can be suppressed. This developing device comprises a developing roller for developing an electrostatic latent image supported on a photoconductive member, a supply developer holding chamber for holding toner to be supplied to the developing roller, a supply roller for supplying the toner supported on the peripheral face thereof to the developing roller, a hopper that is disposed above the supply developer holding chamber and used to hold toner for replenishing the supply developer holding chamber, and a communication opening for allowing the hopper to communicate with the supply agent holding chamber, wherein a canopy member is provided directly above the gap to impede the advance of the toner on the supply roller into the gap between the supply roller and the opposing side wall of the supply developer holding chamber.