Fixing Nip Pressure Control for Sheet Speed Transitions
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Solution Overview
Problem
Existing image forming apparatuses face durability issues with fixing members when conveying speed and fixing pressure are switched during mixed sheet feeding, leading to potential degradation of the fixing member's performance.
Innovation Solution
An image forming apparatus with a toner-image fixer and a pressing force changer, controlled by a hardware processor, which adjusts the conveying speed by decreasing the pressing force when changing the sheet's conveying speed, thereby minimizing the load on the fixing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conveying speed and fixing pressure are switched simultaneously during mixed sheet feeding, then productivity is improved by maintaining continuous printing, but durability of the fixing member deteriorates due to increased load
Solution Approach 1:
The pressing force is decreased before the conveying speed is changed. The control unit decreases the pressing force applied by the fixing member to the sheet in advance, and then changes the conveying speed. This preliminary action reduces the load on the fixing member before speed changes, preventing durability degradation while maintaining continuous printing capability.
Solution Approach 2:
The pressing force is dynamically adjusted based on the conveying speed change. The control unit changes the pressing force according to the conveying speed change, making the fixing system adaptive to operational conditions. This dynamic adjustment ensures optimal performance while protecting the fixing member during speed transitions.
2Adaptability or versatility
If conveying speed is changed during mixed sheet feeding, then adaptability to various sheet conditions is improved, but load on fixing member increases causing durability issues
Solution Approach 1:
Before changing the conveying speed to adapt to different sheet conditions, the control unit first decreases the pressing force. This preliminary reduction in force protects the fixing member from excessive load during the speed transition, enabling versatile sheet handling while maintaining reliability.
Solution Approach 2:
The control unit changes the pressing force parameter in response to conveying speed changes. By adjusting the pressing force according to the new conveying speed, the system adapts to various sheet conditions while protecting the fixing member from damage during parameter transitions.
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 approach enhances the durability of the fixing member by reducing the risk of damage during speed and pressure changes, ensuring continuous printing without entering a standby state and maintaining fixability and sheet conveying properties.
Implementation Method 1
a toner-image fixer that fixes an unfixed toner image on a sheet by conveying the sheet while heating and pressing the sheet at a fixing nip
Data Source
AI summary
An image forming apparatus includes: a toner-image fixer that fixes an unfixed toner image on a sheet by conveying the sheet while heating and pressing the sheet at a fixing nip; a pressing force changer that changes a pressing force against the sheet at the fixing nip; and a hardware processor that controls the toner-image fixer and the pressing force changer, in which when a conveying speed of the sheet is changed by controlling the toner-image fixer, the hardware processor causes the conveying speed to change in a state in which the pressing force is decreased by controlling the pressing force changer.