Rotatable Curl Correcting Device for Sheet Conveyance
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Solution Overview
Problem
Conventional curl correcting devices for sheets in image forming apparatuses can inadvertently curl uncurled sheets, leading to storage and handling issues.
Innovation Solution
A curl correcting device with a rotating unit comprising a hard roller and an elastic roller, supported by a rotary shaft, forms a curved nip portion to correct curls, and includes a conveyance path system with distinct sections to prevent uncurled sheets from being curled, by positioning the unit to either include or exclude the nip portion based on the sheet's curl status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sheet is carried into the nip portion between hard roller and elastic roller, then a curl of the sheet is corrected, but the sheet is rather curled if it was not curled before
Solution Approach 1:
The curl correcting device is made rotatable about a third rotary shaft, allowing dynamic repositioning between a first position where the conveyance path includes the nip portion and a second position where it excludes the nip portion. This dynamic adjustment enables the system to adapt to different sheet conditions, applying curl correction only when necessary and avoiding unnecessary curling of already flat sheets.
Solution Approach 2:
The conveyance path is segmented into two distinct configurations: a first conveyance path that includes the nip portion for curl correction, and a second conveyance path that excludes the nip portion for non-curling operation. This segmentation allows the system to selectively engage or disengage the curl correction function based on sheet condition, resolving the contradiction between effective curl correction and avoidance of unnecessary curling.
2Adaptability or versatility
If the curl correcting device is vertically inverted to deal with both upward and downward curls, then versatility is improved, but the problem of curling uncurled sheets remains
Solution Approach 1:
Instead of relying on vertical inversion to handle different curl directions, the invention employs a rotatable supporting unit that can dynamically reposition the curl correcting device between different operational configurations. This dynamic repositioning provides versatility in handling various sheet conditions while avoiding the harmful effect of curling uncurled sheets, as the system can selectively engage the nip portion only when curl correction is needed.
Solution Approach 2:
The rotatable supporting unit provides multi-functionality by enabling the same curl correcting device to operate in different configurations: one for correcting curls and another for conveying sheets without applying curl correction. This universal design replaces the need for vertical inversion while maintaining the ability to handle various sheet conditions and avoiding unnecessary curling.
3Reliability
If the nip portion is always present in the conveyance path, then curl correction is always available, but uncurled sheets are inadvertently curled
Solution Approach 1:
The nip portion's presence in the conveyance path is made dynamic rather than static. The supporting unit can rotate to position the curl correcting device such that the nip portion is either included in or excluded from the conveyance path, depending on whether curl correction is needed. This dynamic control ensures curl correction availability when required while preventing inadvertent curling of uncurled sheets, thereby improving sheet handling quality.
Solution Approach 2:
The nip portion can be extracted from the conveyance path by rotating the supporting unit to a second position where the conveyance path excludes the nip portion. This extraction allows the system to maintain curl correction capability when needed while avoiding its application to uncurled sheets, thus preventing harmful side effects and improving overall operation quality.
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
Effectively corrects curls in sheets while preventing uncurled sheets from being curled, ensuring stable sheet storage and handling by dynamically adjusting the position of the curl correcting unit within the conveyance path.
Implementation Method 1
The second roller elastically deforms the first roller by being pressed against the first roller, thereby forming a curved nip portion between the first and second rollers
Data Source
AI summary
A curl correcting device includes a first roller, a second roller and a supporting unit. The supporting unit includes a first conveyance path and a second conveyance path. The first roller is rotated about a first rotary shaft and elastically deformable. The second roller is rotated about a second rotary shaft and elastically deforms the first roller by being pressed against the first roller, thereby forming a curved nip portion between the first and second rollers. The supporting unit is rotatable about a third rotary shaft and rotatably supports the first and second rollers. The first conveyance path communicates with the sheet conveyance path by the supporting unit being arranged at a first position about the third rotary shaft. The second conveyance path communicates with the sheet conveyance path by the supporting unit being arranged at a second position about the third rotary shaft.