Multi-stage Cooling and Uncurling for Toner Adhesion Prevention
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Solution Overview
Problem
Existing image forming apparatuses face challenges in simultaneously cooling and uncurling sheets of recording medium effectively, leading to potential toner nonuniformity and adhesion issues, as cooling before uncurling can result in inadequate uncurling or overcooling.
Innovation Solution
An image forming system comprising a main assembly, image forming unit, fixing device, first cooling device, curl reducing device, and second cooling device, where the first cooling device cools the sheet after fixation, and the curl reducing device, followed by a second cooling device, ensures proper cooling and uncurling by controlling temperature levels through multiple cooling stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a sheet of recording medium is cooled by a cooling apparatus before it is uncurled by an uncurling apparatus, then the sheet is cooled to prevent toner adhesion and nonuniform gloss, but the sheet may be overcooled such that it is not satisfactorily uncurled
Solution Approach 1:
The cooling process is divided into two distinct stages: first cooling apparatus (20) positioned before the uncurling apparatus (700) performs initial cooling to a first temperature level that prevents toner adhesion, then the sheet is uncurled, and finally the second cooling apparatus (201) performs additional cooling to a second temperature level for optimal stacking. This segmentation allows each cooling stage to serve a specific purpose without interfering with the uncurling process.
Solution Approach 2:
The first cooling apparatus (20) performs preliminary cooling of the sheet to a first temperature level before the sheet enters the uncurling apparatus (700). This preliminary cooling action is sufficient to prevent toner adhesion and nonuniform gloss during the uncurling process, while maintaining the sheet temperature at a level that does not hinder effective uncurling.
2Ease of operation
If a sheet of recording medium is conveyed to an uncurling apparatus while remaining higher in temperature than a preset level, then the sheet can be easily uncurled, but the toner on the sheet will adhere to the uncurling apparatus causing nonuniform gloss and soiling
Solution Approach 1:
The cooling function is segmented between two apparatuses: the first cooling apparatus (20) handles the critical task of cooling the sheet to prevent toner adhesion before uncurling, while the second cooling apparatus (201) handles post-uncurling cooling for stacking. This segmentation ensures that the sheet is at the appropriate temperature for uncurling without risking toner adhesion.
Solution Approach 2:
The first cooling apparatus (20) acts as an intermediary between the fixing apparatus (11) and the uncurling apparatus (700), mediating the temperature of the sheet to a level that is cool enough to prevent toner adhesion but warm enough to allow effective uncurling. This intermediary cooling action resolves the contradiction between preventing toner adhesion and maintaining uncurling effectiveness.
3Object-generated harmful factors
If a sheet of recording medium is cooled by a cooling apparatus before it is uncurled, then toner adhesion is prevented, but additional cooling apparatuses are required to maintain both cooling and uncurling effectiveness
Solution Approach 1:
Both the first cooling apparatus (20) and the second cooling apparatus (201) use the same cooling mechanism (cooling belts with cooling rollers), demonstrating multi-functionality in design. While two apparatuses are used, they share the same technological approach, reducing the complexity increment compared to using fundamentally different cooling methods.
Solution Approach 2:
The cooling function is segmented into two distinct apparatuses positioned at different locations in the sheet path, with each apparatus performing a specific cooling task at a specific temperature level. This segmentation, while increasing the number of components, allows for simplified control and optimization of each individual cooling stage.
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 system effectively cools and uncurls sheets, preventing toner nonuniformity and adhesion, ensuring reliable image formation and stacking by maintaining optimal temperature ranges for both processes.
Implementation Method 1
The first cooling device is capable of cooling the recording material that has been passed through said fixing device
Implementation Method 2
The second cooling device is capable of cooling the recording material that has been passed through said curl reducing device
Implementation Method 3
The fixing device is configured to heat the recording material carrying the toner image formed by said image forming unit to fix the toner image on the recording material
Data Source
AI summary
In a feeding direction of a recording material, a recording material cooling device is provided downstream of a fixing device, a curl reducing device is provided downstream of the recording material cooling device, and another recording material cooling device is provided downstream of the curl reducing device. By this configuration, occurrence of image defect by the recording material cooling device during the feeding of the recording material can be suppressed, and the curling of the recording material can be reduced after the recording material is cooled.