Fixing Portion Cooling for Large Media Offset
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Solution Overview
Problem
Conventional image forming apparatuses experience productivity drops due to the need for cooling downtime when switching from small-sized to large-sized recording materials, leading to toner offset and reduced image quality.
Innovation Solution
An image forming apparatus with a control system that executes a cooling sequence for the non-passing region of the fixing portion before fixing a toner image on a larger recording material, based on the image information of the non-passing region, allowing for immediate printing without downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cooling sequence is executed for the non-passing region before fixing a toner image on a larger recording material, then image quality is maintained by preventing toner offset, but processing time increases due to the cooling step
Solution Approach 1:
The control portion executes the cooling sequence for the non-passing region in advance, before the larger recording material is conveyed through the fixing portion. This preliminary cooling action prevents toner offset during subsequent fixing operations on wide sheets, thereby maintaining image quality without requiring post-cooling downtime.
2Temperature
If cooling processing is performed on the fixing unit after small-sized recording materials are continuously passed, then temperature rise in the non-sheet-passing region is reduced, but productivity drops due to downtime
Solution Approach 1:
Instead of cooling the fixing unit after small-sized materials are processed (which causes downtime), the control portion performs cooling of the non-passing region in advance, before the larger recording material is conveyed. This timing shift eliminates the need to stop processing for cooling, thereby maintaining productivity while still controlling temperature to prevent toner offset.
Solution Approach 2:
The cooling sequence is applied specifically to the non-passing region of the fixing portion, rather than cooling the entire fixing unit. This localized cooling approach efficiently reduces temperature in the critical area where toner offset occurs, while minimizing the impact on overall processing efficiency.
3Temperature
If a blower fan is installed to forcibly cool the non-sheet-passing region, then temperature rise is reduced, but device complexity increases
Solution Approach 1:
The control portion utilizes the existing cooling capability of the fixing unit to perform self-cooling of the non-passing region by controlling the timing of cooling operations. This approach eliminates the need for additional active cooling components like blower fans, thereby reducing device complexity while still achieving effective temperature control to prevent toner offset.
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 reduces downtime and maintains high image quality by preventing toner offset, thus enhancing productivity when handling larger recording materials.
Implementation Method 1
a fixing portion that fixes a toner image formed on a recording material onto the recording material by using heat
Implementation Method 2
the control portion can execute a cooling sequence to cool a non-passing region of the fixing portion
Data Source
AI summary
An apparatus includes a control portion. When a toner image formed on a first recording material is fixed onto the first recording material by the fixing portion, and then an image is formed on a second recording material of which width is larger than that of the first recording material, the control portion can execute a cooling sequence to cool a non-passing region of the fixing portion through which the second recording material passes but the first recording material does not pass, before the toner image formed on the second recording material is fixed by the fixing portion. The control portion sets an execution condition to execute the cooling sequence in accordance with information on the toner image in the region of the second recording material corresponding to the non-passing region.