Dynamic Sheet Conveyance for Fixing Temperature Control
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Solution Overview
Problem
Electrophotographic image forming apparatuses face challenges in controlling sheet conveyance for double-sided printing, particularly in maintaining the fixing temperature of the rotator in systems that convey a large number of sheets per unit time, leading to potential decreases in productivity and fixing strength.
Innovation Solution
The implementation of a conveying system that adjusts the number of sheets conveyed based on the calculated amount of toner per unit area, allowing for simultaneous conveyance of a larger number of sheets when toner is scarce and a smaller number when toner is abundant, thereby optimizing temperature recovery and fixing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of sheets are conveyed simultaneously to improve productivity, then the printing speed increases, but the rotator temperature drops below the fixing temperature causing inadequate fixing strength
Solution Approach 1:
The patent applies dynamics by making the number of sheets conveyed simultaneously variable rather than fixed. The conveying system dynamically adjusts the sheet volume based on real-time rotator temperature conditions, allowing the system to optimize between productivity and fixing quality adaptively throughout the printing process
Solution Approach 2:
The patent changes the parameter of sheet conveyance quantity based on temperature conditions. When the rotator temperature is sufficient, a larger number of sheets are conveyed to maximize productivity. When temperature drops, the system reduces the conveyed sheet count to allow proper temperature recovery, thus maintaining fixing strength
2Reliability
If a small number of sheets are conveyed simultaneously to maintain fixing temperature, then fixing strength is secured, but productivity decreases
Solution Approach 1:
The system dynamically adjusts the conveying quantity based on temperature feedback. Rather than maintaining a fixed low sheet count, the system increases conveyance when temperature conditions permit, thereby recovering productivity while maintaining fixing quality when possible
Solution Approach 2:
The patent maintains continuous productive operation by minimizing temperature-related interruptions. By optimizing sheet conveyance timing and quantity based on temperature conditions, the system keeps the rotator operating continuously at effective temperatures, reducing idle time and maintaining high productivity
3Productivity
If the rotator temperature is allowed to drop to process more sheets, then more sheets can be processed, but the temperature recovery time becomes insufficient for subsequent sheets
Solution Approach 1:
The system performs preliminary temperature assessment before initiating sheet conveyance. By predicting whether sufficient temperature recovery time will be available based on the current temperature and scheduled conveyance timing, the system prevents situations where temperature recovery becomes insufficient
Solution Approach 2:
The patent implements feedback control by continuously monitoring rotator temperature and using this information to adjust subsequent conveyance decisions. The temperature measurement feedback loop allows the system to learn from past temperature drops and optimize conveyance scheduling to prevent insufficient recovery time
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 productivity by allowing for high-speed double-sided printing while ensuring adequate fixing strength, even with varying toner densities, by dynamically adjusting the sheet conveyance process according to toner distribution across pages.
Implementation Method 1
a fixing unit including a heater and a rotator configured to be heated by the heater
Data Source
AI summary
An image forming apparatus has a feed tray, a transferring unit, a fixing unit, a output tray, a conveying unit for conveying a sheet along a sheet conveyance path including a first sheet conveyance path and a second sheet conveyance path which branches from the first sheet conveyance path on a downstream side and joins to the first sheet conveyance path on a upstream side, and a controller. The controller causes the conveying unit to convey sheets, calculates a specific amount related to the amount of toner per unit area of a page in image data, performs double-sided printing with the large number of sheets conveyed in a case where the specific amount is smaller than a predetermined amount, and performs double-sided printing with the small number of sheets conveyed in a case where the specific amount is equal to or larger than the predetermined amount.