Compressor Air Ejection for Sheet Separation in Fixing Units
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining stable air pressure for effective separation and cleaning, leading to potential jams and image quality issues due to the difficulty in monitoring and controlling air pressure, which can result in increased costs and apparatus size from requiring additional sensors and mechanisms.
Innovation Solution
The apparatus includes a compressor that outputs air based on a drive current, with a detection portion to monitor the drive current and a determination unit to calculate a characteristic expression for air pressure, allowing for normal air pressure monitoring and adjustment without additional sensors, ensuring stable separation and cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separation claw is used to peel off the sheet from the heating roller, then sheet separation is achieved, but the sheet edge is scratched and image quality deteriorates when dealing with thin paper or coated paper with high-density images
Solution Approach 1:
The patent replaces the mechanical separation claw with a pneumatic system using compressed air ejection. The compressed air blows between the sheet and heating roller to create a gap, enabling separation without mechanical contact. This eliminates the scratching issue while maintaining effective sheet separation, particularly for thin paper and coated paper with high-density images.
Solution Approach 2:
The invention uses compressed air ejection from nozzles positioned near the heating roller. The pneumatic pressure creates a separation gap between the sheet and heating roller surface, allowing the sheet to be peeled off without mechanical contact. This pneumatic approach resolves the contradiction by providing separation force without the harmful mechanical contact that causes edge scratches.
2Measurement precision
If additional sensors and mechanisms are added to monitor air pressure, then air pressure control accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The compressor unit itself serves as the monitoring device by detecting its own drive current. The control unit calculates air pressure based on the drive current signal from the compressor motor, eliminating the need for separate pressure sensors. This self-monitoring approach reduces device complexity while maintaining adequate air pressure control for the pneumatic separation system.
Solution Approach 2:
The patent replaces mechanical pressure sensors with an electrical measurement approach. By monitoring the drive current of the compressor motor and using calculation to determine air pressure, the system achieves pressure monitoring without physical sensors. This substitution reduces component count and device complexity while providing sufficient control capability.
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 solution enables accurate monitoring and adjustment of air pressure, preventing jams and image quality issues, reducing the need for additional sensors and mechanisms, and extending the life of fixing rollers by maintaining stable separation and cleaning performance.
Implementation Method 1
a compressor configured to output air based on a drive current supplied from a power source
Implementation Method 2
a detection portion configured to detect the drive current
Implementation Method 3
applying heat and pressure to the sheet to melt the unfixed toner, to thereby fix the melted toner to the sheet
Implementation Method 4
applying heat and pressure to the sheet
Data Source
AI summary
An image forming apparatus includes an image forming unit that forms a toner image, a transfer portion that transfers the toner image onto a sheet, and a fixing unit that fixes the toner image to the sheet. A compressor outputs air based on a drive current supplied from a power source, and a detection portion detects the drive current. An ejection portion ejects the air output from the compressor, and a pipe supplies the air output from the compressor to the ejection portion. In addition, a determination unit determines a characteristic expression indicating a relationship between the drive current and an air pressure of the air based on a first detection result obtained by the detection portion when the air pressure is adjusted to a first predetermined value and a second detection result obtained by the detection portion when the air pressure is adjusted to a second predetermined value.