Heating Roller Spacing Control for Thermal Management
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Solution Overview
Problem
Existing image forming apparatuses face productivity reduction due to excessive temperature rise of the fixing belt, which is not adequately suppressed when sheet feeding clearance is short, leading to delayed job resumption and reduced throughput.
Innovation Solution
An image forming apparatus with a changing mechanism that adjusts the relative positional relation between the rotatable heating member and the pressing rotatable member to a first spacing position when the pause period is longer than a predetermined time, and to a second spacing position when it is shorter, allowing for quicker resumption of the job and reduced temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the belt is spaced from the fixing roller to suppress excessive heating, then the temperature control is improved, but the job resumption is delayed and productivity is reduced
Solution Approach 1:
The patent applies dynamics by making the spacing distance between the belt and fixing roller variable rather than fixed. The spacing mechanism adjusts the separation distance based on the duration of pause detected by the control unit, providing optimal temperature control for long pauses while minimizing productivity impact for short pauses.
Solution Approach 2:
The patent changes the parameter of spacing distance based on pause duration. When pause duration exceeds a threshold, the system increases spacing distance to suppress belt temperature rise; when pause duration is short, the system maintains smaller spacing to minimize job resumption delay. This dynamic parameter adjustment resolves the contradiction between temperature control and productivity.
2Temperature
If the belt spacing time is longer than the pause period, then the temperature control is effective, but the job resumption is delayed
Solution Approach 1:
The system dynamically adjusts spacing distance based on detected pause duration. For short pauses where spacing would exceed the pause period, the system maintains a smaller spacing distance that allows quick resumption. For long pauses, it increases spacing to ensure effective temperature control, making the spacing strategy adaptive to actual pause conditions.
Solution Approach 2:
The control unit detects pause duration in advance and determines the appropriate spacing distance before the pause ends. This preliminary assessment allows the system to prepare the optimal spacing configuration, ensuring that when the pause ends, the belt is positioned at the correct distance to either resume quickly or maintain temperature control, avoiding delays.
3Productivity
If the sheet feeding clearance is short, then the continuous operation capability is improved, but the excessive temperature rise of the belt cannot be sufficiently suppressed
Solution Approach 1:
The patent implements dynamic spacing adjustment that works independently of sheet feeding clearance. Even with short clearance that limits mechanical spacing range, the system uses the maximum available spacing distance combined with pause duration detection to suppress belt temperature rise, while maintaining continuous operation capability through quick resumption for short pauses.
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 effectively suppresses excessive temperature rise of the fixing belt, enabling quicker job resumption and maintaining throughput even during short pause periods, thus preventing productivity reduction.
Implementation Method 1
the belt is gradually heated by the heat of the fixing roller since the belt (pressing rotatable member) is contacted to the fixing roller
Data Source
AI summary
An image forming apparatus includes: an image forming station; heating and pressing rollers forming a fixing nip therebetween; a mechanism for changing the relative positional relation between the heating and pressing rollers between a contacting position in which they contact each other, a first spacing position in which they are spaced, and the second spacing position in which they are spaced by a shorter distance; and a controller for controlling the changing mechanism such that in a period after the sheet passes through the fixing nip and before a next sheet reaches the fixing nip, the rollers are brought into the first spacing position when the period is longer than a first predetermined period, and that the rollers are brought into the second spacing position when the period is shorter than the first predetermined period and is longer than a second predetermined period.