Separator Recesses for Friction Reduction in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face issues with efficiently separating recording media from fixing rotators without causing damage to the toner images, such as gloss streaks and scratches, due to improper alignment and thermal expansion of components.
Innovation Solution
A separation device with a conveyance path side face featuring a series of obliquely extending recesses that reduce friction and prevent jamming, allowing for even contact and smooth separation of the recording medium from the fixing nip, while accommodating thermal expansion of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional separator with a flat conveyance path side face is used, then the structure is simple, but the recording medium may jam or cause gloss streaks on the toner image due to improper alignment and friction
Solution Approach 1:
The separator's conveyance path side face is designed with localized recesses at specific positions rather than a uniformly complex structure. These recesses are strategically placed to align with the recording medium width, providing local friction reduction and alignment assistance only where needed, while maintaining a relatively simple overall separator structure.
Solution Approach 2:
The recesses on the separator's conveyance path side face have curved bottom surfaces instead of sharp angles. This curvature allows the recording medium to smoothly contact and separate from the separator without creating stress concentration points, reducing the risk of jamming and gloss streaks while maintaining structural simplicity.
2Measurement precision
If the separator contacts the recording medium over a large area, then alignment is improved, but friction increases causing jamming and gloss streaks
Solution Approach 1:
The contact area between the separator and recording medium is segmented into multiple discrete recesses rather than a continuous large-area contact. Each recess is sized and positioned to provide localized alignment assistance, while the gaps between recesses reduce overall friction and prevent jamming. The recesses extend in the conveyance direction to maintain alignment without excessive friction.
3Reliability
If the separator is positioned close to the fixing nip, then separation effectiveness is improved, but thermal expansion effects increase causing misalignment
Solution Approach 1:
The recesses on the separator are designed with dimensions and positions that anticipate thermal expansion effects. By pre-configuring the recess geometry and spacing, the separator maintains proper alignment with the recording medium even when thermal expansion occurs during operation, cushioning against misalignment before it affects separation effectiveness.
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
The solution effectively prevents gloss streaks and scratches on the toner image by reducing friction and ensuring even separation, improving the conveyance of the recording medium and maintaining image quality.
Implementation Method 1
A plurality of recesses is disposed on a conveyance path side face of the separator... effectively prevents gloss streaks and scratches on the toner image by reducing friction
Data Source
AI summary
A separation device includes a separator that separates a recording medium from a rotator and a plurality of recesses disposed on a conveyance path side face of the separator over which the recording medium is conveyed in a recess span in a recording medium conveyance direction and at least in a conveyance span where the recording medium is conveyed. The plurality of recesses includes a first recess extending in a first extension line that is oblique relative to the recording medium conveyance direction and a second recess being adjacent to the first recess in a direction perpendicular to the recording medium conveyance direction. The second recess extends in a second extension line that is oblique relative to the recording medium conveyance direction and overlaps the first extension line of the first recess in the direction perpendicular to the recording medium conveyance direction to define an overlap span.