Sheet Conveying Apparatus Roller Release Mechanism
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Solution Overview
Problem
Existing sheet conveying apparatuses face challenges in avoiding sheet curl when switching conveyance direction, particularly with thick sheets like cardboard, which can lead to jams and degradation.
Innovation Solution
The apparatus includes a first and second sheet conveyance passage, a switch guide, a pair of feed rollers, and a contact-release mechanism. The contact-release mechanism allows the second roller to move apart from the first roller, increasing the sheet's radius of curvature in the branch section, thus preventing curl without enlarging the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the conveyance passage is switched from horizontal to downward direction, then the sheet conveyance destination is changed, but the sheet is conveyed in a bent state which may cause curl
Solution Approach 1:
The roller is configured to be movable between a contact state (pressing against the sheet) and a release state (separated from the sheet). During direction switching, the roller releases from the sheet to avoid causing curl, while during normal conveyance it contacts the sheet to provide guidance. This dynamic state change allows the system to adapt to different operational requirements.
Solution Approach 2:
The roller is positioned upstream of the branch section and is configured to release from the sheet before the sheet reaches the sharp bend at the branch section. This preliminary release action prevents the roller from causing curl during the critical bending phase, while still providing guidance during straight conveyance sections.
2Reliability
If the roller diameter is increased to avoid sheet curl, then the sheet conveyance reliability is improved, but the apparatus size increases
Solution Approach 1:
Instead of using a large-diameter roller that would increase apparatus size, the invention uses a small-diameter roller that dynamically changes its state. The roller moves between contact and release states, effectively preventing curl during direction switching without requiring increased roller diameter or apparatus volume.
Solution Approach 2:
The system changes the operational parameter of the roller from a fixed contact state to a variable state (contact/release). This parameter change allows the small roller to achieve the curl-prevention effect of a large roller without the size penalty, by adjusting its contact pressure and position dynamically.
Data Source
AI summary
A sheet conveying apparatus (20) includes a first sheet conveyance passage (3), a second sheet conveyance passage (5), a pair of feed rollers (3r1), a first pair of conveyance rollers (50), and a contact-release mechanism (60). The second sheet conveyance passage (5) branches from a branch section (31) on the first sheet conveyance passage (3). The first pair of conveyance rollers (50) has a first roller (51) and a second roller (52) and conveys a sheet along the first sheet conveyance passage (3). When, in the branch section (31), a sheet is conveyed from upstream with respect to the sheet conveyance direction in the first sheet conveyance passage (3) toward the second sheet conveyance passage (5), the sheet conveying apparatus (20) makes the contact-release mechanism (60) move the second roller (52) away from the first roller (51) and makes the pair of feed rollers (3r1) convey the sheet.