Dual Air Blowing Fixing Device for Toner Separation
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Solution Overview
Problem
Conventional fixing devices for toner images on recording sheets require large-power compressors and bulky designs to separate sheets from fixing members using compressed air, often causing scratches and inefficiencies, especially with coated papers and color images.
Innovation Solution
A fixing device employing a dual air blowing system where a high-velocity, low-volume first blowing unit precedes a low-velocity, high-volume second blowing unit to separate the recording sheet from the fixing member, utilizing a compressor for the first unit and a fan for the second, optimizing air usage and preventing surface scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single high-power compressor is used to blow air for separation, then the separation effect is sufficient, but the device size and power consumption increase
Solution Approach 1:
The air blowing function is segmented into two distinct units: a first blowing unit with high air velocity for initial separation, and a second blowing unit with high air volume for sustained separation. This segmentation allows each unit to operate at optimized power levels rather than requiring one large compressor, thereby reducing overall power consumption while maintaining effective separation
Solution Approach 2:
The two blowing units operate in a periodic sequence rather than simultaneously at full power. The first blowing unit operates initially to create the separation effect, then the second blowing unit takes over to maintain separation. This periodic operation pattern reduces peak power demands and average power consumption compared to continuous high-power operation
2Reliability
If a separation claw is used to separate the recording sheet, then separation is achieved, but the fixing member surface is scratched
Solution Approach 1:
The mechanical contact-based separation claw is replaced with a pneumatic separation system that uses air flow to achieve separation. The first and second blowing units generate air flow that lifts and separates the recording sheet from the fixing member surface without physical contact, thereby eliminating the scratching problem while maintaining effective separation
Solution Approach 2:
Air flow is introduced as an intermediary medium between the separation mechanism and the recording sheet. Instead of direct mechanical contact between the separation claw and the sheet, air flow acts as a mediator that creates a cushion and applies lifting force, preventing direct contact that would cause surface damage
3Productivity
If the nip width is increased to cope with increasing image forming speed, then productivity improves, but the roller curvature at the nip outlet is reduced, further reducing sheet separability
Solution Approach 1:
The air blowing parameters (velocity and volume) are optimized to compensate for the reduced roller curvature effect. By adjusting the air flow characteristics of the two blowing units, the system achieves effective separation despite the geometric changes caused by larger nip width, thereby maintaining sheet separability while enabling higher productivity
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 reduces the size and power consumption of the device while ensuring effective separation of recording sheets from fixing members, maintaining image quality and preventing paper jams, even with coated papers and color images.
Implementation Method 1
a first blowing unit which separates the recording medium from the fixing member by blowing air to the recording medium
Implementation Method 2
a second blowing unit which separates the recording medium from the fixing member by blowing air to the recording medium
Implementation Method 3
a heated fixing member, a pressure member to form a nip portion between the pressure member and the fixing member, wherein the fixing member and the pressure member fix a toner image on a recording medium
Data Source
AI summary
A fixing device including: a fixing member that is heated; a pressure member to form a nip portion between the pressure member and the fixing member; first blowing unit and second blowing unit both located close to an outlet of the nip portion and separate the recording medium from the fixing member by blowing air to the recording medium, a velocity of the air discharged from the first unit is higher than that of the air discharged from the second unit, whereas a volume of the air discharged from the first unit is smaller than that of the air discharged from the second unit; and the first unit starts discharging air before a leading edge of the recording medium reaches the outlet of the nip portion, whereas the second unit starts discharging air after the leading edge of the recording medium has passed through the outlet of the nip portion.