Wavy Separation Member for Image Defect Prevention
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Solution Overview
Problem
In image forming apparatuses, the separation of recording media from fixing rollers or belts can lead to image defects and streaked images due to toner contact with separation members, especially when using less rigid media, and results in increased conveyance resistance.
Innovation Solution
A separation member with a wavy part having inclined grooves and projections is used, which reduces contact pressure and adherence, allowing for smooth separation of the recording media without causing image defects, even with less rigid media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separation member with a flat conveyance surface is used to strip off the recording medium, then the separation function is achieved, but the toner image comes into contact with the conveyance surface causing streaked images and image defects
Solution Approach 1:
The conveyance surface is divided into different regions with different properties: a first conveyance surface for contact with the recording medium and a second conveyance surface with a different shape. The first surface provides good contact for separation, while the second surface with protrusions or recesses reduces toner contact area, preventing streaked images
Solution Approach 2:
The invention transitions from a flat two-dimensional conveyance surface to a three-dimensional surface with protrusions or recesses. This dimensional change creates regions that minimize toner contact while maintaining separation effectiveness
2Reliability
If a separation member with concentrated contact force at the end is used, then separation is achieved, but less rigid recording media experience severe streaked images
Solution Approach 1:
The conveyance surface is segmented into multiple contact regions through protrusions or recesses. This segmentation distributes the contact force across multiple points rather than concentrating it at one end, reducing damage to less rigid recording media while maintaining separation effectiveness
3Reliability
If the separation member forcibly separates the recording medium from the fixing roller, then separation is achieved, but conveyance resistance increases due to toner adherence
Solution Approach 1:
The invention extracts or removes the harmful adhering toner from the conveyance surface through the protrusion-recess structure. The recesses allow toner to be separated from the surface, reducing adherence and conveyance resistance while maintaining the separation function
Data Source
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AI summary
A separation member 36 that separates a conveyance object P from a rotation member 26, the conveyance object P having been sent out from a nip N2 that is formed by two rotation members 26 and 27 that are in contact with one another. The separation member 36 includes a wavy part 39 directed toward the nip N2 and inclined from a normal to a center line of the two rotation members 26 and 27. The wavy part 39 covers a sheet passing zone Q where the conveyance object P can come into contact with the separation member 36 along a conveyance direction B and along a width direction Y of the conveyance object P. The wavy part 36 has a plurality of depressions 39a parallel to each other and extending in a direction inclined from the conveyance direction B and inclined from the width direction Y, and at least two of the depressions 39a overlap along the conveyance direction B.