Fixing Device Water Vapor Discharge Passage
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Solution Overview
Problem
In image forming apparatuses, water vapor from the fixing device can condense in the sheet conveying path and non-contact temperature detection elements, leading to damp sheets and reduced temperature detection accuracy, and the use of fans to exhaust vapor cools these elements and decreases heating efficiency.
Innovation Solution
A fixing device with a water vapor discharge passage downstream of the nip, separated from the media conveyance path, utilizing partition wall members to prevent vapor permeation and a duct for vapor discharge, eliminating the need for fans to maintain accurate temperature detection and heating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fan is used to exhaust water vapor from the fixing device, then condensation in the conveying path is prevented, but the non-contact temperature detection element is cooled causing deteriorated temperature detection accuracy
Solution Approach 1:
The apparatus is divided into separate functional zones: a water vapor discharge passage for removing moisture and a distinct detection zone for temperature measurement. This segmentation allows water vapor to be exhausted without directly contacting the temperature detection element, preventing condensation while maintaining accurate temperature detection.
Solution Approach 2:
A water vapor discharge passage acts as an intermediary channel that redirects water vapor away from the temperature detection element. The passage serves as a mediator between the water vapor source (fixing device) and the detection element, allowing vapor removal without direct interaction that would cause cooling and accuracy deterioration.
2Object-affected harmful factors
If a fan is used to exhaust water vapor, then vapor condensation is prevented, but the fixing device is cooled causing deteriorated heating efficiency
Solution Approach 1:
The water vapor discharge passage extracts and removes water vapor from the fixing device interior without introducing cooling air flows. By taking out only the harmful water vapor component through a dedicated passage rather than using a fan that introduces ambient air, the heating efficiency is maintained while still preventing condensation.
Solution Approach 2:
The water vapor discharge passage serves as an intermediary that selectively removes water vapor through diffusion or pressure differential without requiring fan-driven air flows that would cool the fixing device. This mediator approach allows vapor removal while preserving thermal conditions for efficient heating.
3Device complexity
If water vapor is allowed to permeate into the conveying path, then no additional discharge structure is needed, but subsequent sheets become damp and condensation occurs
Solution Approach 1:
The conveying path is segmented from the water vapor generation zone by introducing a dedicated water vapor discharge passage. This segmentation creates separate zones: one for paper conveyance and another for water vapor removal, preventing vapor permeation into the conveying path while maintaining relatively simple overall device structure.
Solution Approach 2:
The water vapor discharge passage acts as an intermediary barrier and removal channel between the water vapor source and the conveying path. It mediates by providing a controlled exit for water vapor that prevents uncontrolled permeation into the conveying path, thereby preventing damp sheets and condensation.
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 condensation in the conveying path and maintains accurate temperature detection while enhancing heating efficiency by effectively managing water vapor without cooling the temperature detection elements or the fixing device.
Implementation Method 1
a heater that heats the rotating body
Implementation Method 2
Water vapor is produced from the heated paper
Implementation Method 3
When this water vapor permeates into the sheet conveying path of the printer or the like, the vapor condenses
Data Source
AI summary
According to an embodiment, a fixing device includes rotating body that is rotatably supported, a heater that heats the rotating body, a pressing body that is pressed against the rotating body to form a nip through which print media passes to a media conveyance path, and a water vapor discharge passage downstream of the nip from rotating body. The water vapor discharge passage is separate and distinct from the media conveyance path. The fixing device may be used in image forming apparatuses and the like.