Developing Device Side Seal Protrusion for Toner Leakage Control
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Solution Overview
Problem
Existing developing devices face issues with toner leakage due to inefficient seal designs, leading to filler wastage and potential damage to the developing roller, and require complex manufacturing processes to prevent leakage.
Innovation Solution
The developing device incorporates a side seal member with a protrusion to prevent filler spread, a blade rear seal member that protrudes beyond the layer thickness regulating blade to block gaps, and an oblique delivery mechanism for toner to ensure it returns to the supply port, along with a frame seal and blade rear seal member configuration to prevent gaps and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filler is filled in the gap surrounded by the lower film, side seal member, support portion, and side seal attachment surface to suppress toner leakage, then toner leakage is reduced, but the filler spreads wastefully on the side seal attachment surface
Solution Approach 1:
The side seal attachment surface is divided into a filled portion and an unfilled portion by the protrusion. The protrusion creates a boundary that segments the gap filling region, allowing filler to be confined only where needed for toner leakage suppression, preventing wasteful spread across the entire attachment surface.
Solution Approach 2:
The protrusion creates a localized filled region with different properties from the unfilled region. The filler is applied locally only in the gap area that requires toner leakage suppression, rather than uniformly across the entire side seal attachment surface, optimizing material usage.
2Reliability
If the side seal member is crushed by the developing roller to seal between both ends of the developing roller and the developing unit housing, then sealing effectiveness is improved, but the structure becomes more complex
Solution Approach 1:
The side seal member transitions from a static component to a dynamic one that is crushed by the developing roller during operation. This crushing action deforms the side seal member to conform to the gap, improving sealing effectiveness without requiring a complex pre-formed structure.
Solution Approach 2:
The physical state of the side seal member changes under compression from the developing roller. The material properties are altered locally through crushing, enabling the seal to adapt to the gap dimensions and improve sealing performance without complex design.
3Reliability
If the blade rear seal member is disposed inward from both ends of the layer thickness regulating blade to prevent toner leakage, then toner leakage is suppressed, but gaps may still form at the ends
Solution Approach 1:
The blade rear seal member is positioned in advance at the rear surface of the layer thickness regulating blade to prevent toner leakage before it can escape. This preliminary sealing action blocks the escape path of toner at the critical rear surface area.
Solution Approach 2:
The blade rear seal member extends in the vertical direction from the rear surface of the layer thickness regulating blade. By adding this vertical dimension to the sealing structure, toner leakage is blocked at multiple levels, preventing gaps from forming at the ends.
4Ease of manufacture
If the surface member and base material of the side seal member have the same shape in plan view, then manufacturing is simplified, but the base material may be extremely compressed and damage the developing roller
Solution Approach 1:
The side seal member is designed with asymmetric geometry where the surface member and base material have different planar shapes. The surface member has a smaller area than the base material, creating an overhang that prevents the base material from being extremely compressed and contacting the developing roller directly.
Solution Approach 2:
The asymmetric design provides a cushioning effect by ensuring the surface member contacts the developing roller before the base material. This prevents direct extreme compression of the base material against the developing roller, protecting it from damage.
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 reduces filler wastage, prevents toner leakage, and minimizes the risk of developing roller damage, while simplifying the manufacturing process by enhancing seal effectiveness and reliability.
Implementation Method 1
a side seal member which comes into slidable contact with both ends of the developing roller
Implementation Method 2
both edges of the elongated seal member are formed in an oblique direction toward the supply port with a decreasing distance to the downstream side
Implementation Method 3
a lower film (elongated seal member) which extends in the axial direction of the developing roller and comes into slidable contact with the developing roller
Implementation Method 4
a rotatable developing roller which carries toner
Implementation Method 5
with a decreasing distance to the downstream side in the rotation direction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A developing device includes a developer carrier which carries a developer, a developing unit housing which rotatably supports the developer carrier, a side seal member which comes into slidable contact with both ends of the developer carrier, a sheet-like elongated seal member which extends in the axial direction of the developer carrier so as to come into slidable contact with the developer carrier, a side seal attachment surface which is formed in the developing unit housing and to which the side seal member is attached, and a support portion which is formed in the developing unit housing and protrudes toward the developer carrier from the side seal attachment surface to support the elongated seal member. The elongated seal member is attached onto the support portion in a state where both ends thereof overlap the side seal member and are opposite the side seal attachment surface. A filler is filled in a gap surrounded by the elongated seal member, the side seal member, the support portion, and the side seal attachment surface. A protrusion for suppressing the spread of the filler is formed at the side seal attachment surface at a predetermined interval from the support portion.