Fuser Exhaust Duct Layout to Prevent Recording Medium Contamination
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Solution Overview
Problem
In existing image forming apparatuses, unnecessary matter contained in the air sucked into the duct of the exhaust device can fall onto the recording medium passing through the passage portion of the fixing device, leading to potential contamination.
Innovation Solution
A fixing system with a duct that includes a duct with an opening portion, a protruding portion, and a collection portion, which includes a protruding portion that protrudes into the duct from an inner wall surface, and a collection portion positioned below the protruding portion to collect any unnecessary matter generated inside the duct and falling down.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air is sucked into the duct from the outlet side of the passage portion, then the exhaust device can remove air and unnecessary matter, but unnecessary matter may fall onto the recording medium passing through the passage portion
Solution Approach 1:
The duct is divided into multiple functional sections: a suction port section, a flow upward section, and a discharge port section. This segmentation allows the air flow to change direction and creates distinct zones for different functions, preventing unnecessary matter from falling onto the recording medium while maintaining effective exhaust capability.
Solution Approach 2:
The patent introduces an intermediary structure (the duct with specific geometric configuration) between the suction port and discharge port. This intermediary duct design, where air flows upward and then discharges, acts as a mediator that separates the suction function from the discharge function, preventing direct fallout of unnecessary matter onto the recording medium.
2Object-affected harmful factors
If the duct allows air to flow upward at least once, then unnecessary matter can be prevented from falling onto the recording medium, but the duct structure becomes more complex
Solution Approach 1:
Instead of allowing air to flow horizontally or downward, the patent inverts the flow direction by making it flow upward within the duct. This inversion of the conventional horizontal flow path creates a configuration where unnecessary matter settles away from the recording medium path, achieving contamination prevention through reversed flow geometry.
Solution Approach 2:
The patent transitions from a conventional two-dimensional horizontal duct layout to a three-dimensional configuration with vertical flow components. By introducing the upward flow dimension, the duct utilizes vertical space to separate air flow from the recording medium path, preventing contamination while managing complexity through spatial optimization.
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
Prevents unnecessary matter from falling onto the recording medium passing through the passage of the duct of the exhaust device, effectively collecting and containing any debris within the duct system.
Implementation Method 1
a first rotating body that is heated by a heating unit and is rotated
Implementation Method 2
a fan that generates a force for causing air to be sucked into the duct and causing the sucked air to flow
Data Source
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AI summary
A fixing system includes: a fixing device including a first rotating body that is heated by a heating unit and is rotated, and a second rotating body that is rotated while being in contact with an outer peripheral surface of the first rotating body to form a passage portion through which a recording medium on which a toner image is formed is to pass; and an exhaust device including a duct that allows a part of air present on an outlet side of the passage portion to flow such that the air is sucked in from a suction port, flows upward at least once, and is then discharged to an outside from a discharge port, and a fan that generates a force for causing air to be sucked into the duct and causing the sucked air to flow, in which the duct includes an opening portion that is provided at a position in a middle of a portion of the duct allowing the air to flow upward and takes in air from the outside of the duct, a protruding portion that protrudes into the duct from an inner wall surface portion facing the opening portion, and a collection portion that is provided at a position below the protruding portion and collects unnecessary matter generated inside the duct and falling down.