Image Heating Device Air Separation Mechanism
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Solution Overview
Problem
Conventional image forming apparatuses using endless belts for fixing toner images suffer from unstable material conveyance due to lateral belt shifting, leading to creases and belt damage, and uneven glossiness caused by inconsistent contact time with the fixing roller.
Innovation Solution
An image heating device with a rotatable heating member and air blowing mechanism that ejects air to separate the recording material from the heating member, with air speed varying between the central and end portions to improve separation efficiency and reduce image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an endless belt is stretched and used for fixing, then the apparatus can be downsized and energy saving is improved, but the belt meanders or shifts laterally causing unstable conveyance and belt damage
Solution Approach 1:
The patent introduces guide members as intermediary elements between the endless belt and the rollers. These guide members constrain the belt's lateral movement while allowing the belt to maintain contact with the rollers, thus preventing meandering and shifting without requiring a completely different fixing mechanism
Solution Approach 2:
The patent modifies the physical parameters of the belt system by adjusting the tension and positioning parameters through the guide members. This allows the belt to maintain stable lateral position while still achieving the downsizing and energy saving benefits of the endless belt configuration
2Device complexity
If separation is performed at the central portion of the recording material, then the separation mechanism is simplified, but uneven glossiness occurs due to different contact times
Solution Approach 1:
The patent applies different air speeds to different regions of the recording material. The air blowing means is configured to eject air at higher speeds toward the end portions and lower speeds toward the central portion, creating a localized quality distribution that matches the different separation needs of various regions
Solution Approach 2:
The patent transitions from a static separation approach (single air speed for all regions) to a dynamic approach where air speed varies by position. This dynamic air speed distribution allows simultaneous optimization of separation efficiency and glossiness uniformity across different regions of the recording material
3Productivity
If air blowing is used to separate recording material, then separation speed is improved, but image defects occur due to uneven air speed distribution
Solution Approach 1:
The patent implements local quality control by configuring the air blowing means to provide different air speeds to different regions. The end portions receive higher air speeds for faster separation, while the central portion receives lower air speeds to prevent image defects, thus optimizing both productivity and image quality locally
Solution Approach 2:
The patent creates a copied or mirrored air speed distribution pattern where the air speed varies symmetrically from the center toward both ends. This copied pattern ensures uniform separation performance and image quality across the width of the recording material
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 air separation mechanism enhances the separation of recording materials, reducing image defects like uneven glossiness and extending the lifespan of the fixing device by stabilizing the conveyance process.
Implementation Method 1
blowing means for blowing air; and ejecting means for ejecting air to separate the recording material passing through the nip from the image heating member
Implementation Method 2
ejecting means for ejecting air to separate the recording material passing through the nip from the image heating member, the ejecting means ejecting the air from the blowing means toward the image heating member
Data Source
AI summary
An image heating device includes a rotatable image heating member for heating an image on a recording material and for forming a nip; a blowing member for blowing air; and an ejecting member for ejecting air to separate the recording material passing through the nip from the image heating member, the ejecting member ejecting the air from the blowing member toward the image heating member so that the speed of the air toward an end portion of the image heating member is higher than that of the air toward a central portion of the image heating member with respect to a rotational axis direction of the image heating member.