Folding Device Skew Correction via Reverse Conveyance
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Solution Overview
Problem
Existing image forming systems face challenges in effectively correcting sheet skew and efficiently processing sheets, particularly in overlaying and folding operations, due to limitations in conveyance paths and roller configurations, which can lead to incomplete skew correction and increased complexity in folding apparatus design.
Innovation Solution
The introduction of a sheet processing apparatus with a skew correction roller pair and a receiving path that reverses the sheet conveyance direction, coupled with a switchback conveyance path, allows for precise skew correction and efficient sheet overlay and folding processes, reducing the size and complexity of the folding apparatus while improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional sheet conveyance system is used without reverse conveyance capability, then the device structure is simpler, but skew correction precision is insufficient
Solution Approach 1:
The patent applies reverse conveyance by making the conveyance rollers rotate in the opposite direction to return the sheet to a previous position after skew correction. This inversion of the normal conveyance direction enables precise skew correction while maintaining a relatively simple device structure by utilizing existing rollers for both forward and reverse motion.
2Manufacturing precision
If the sheet conveyance path is extended to allow complete sheet passage for skew correction, then skew correction is more effective, but the apparatus size increases
Solution Approach 1:
The patent introduces a receiving path that branches from the main conveyance path, creating a two-dimensional path structure. This allows the sheet to be diverted to a receiving position after skew correction without requiring a long linear conveyance path, thereby achieving effective skew correction while minimizing apparatus size.
3Reliability
If multiple conveyance rollers are added to improve sheet handling control, then sheet processing reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the conveyance rollers multi-functional by enabling them to perform both forward conveyance and reverse conveyance operations. This eliminates the need for separate rollers for each direction, maintaining reliable sheet handling control while avoiding the complexity of additional roller configurations.
4Productivity
If the sheet is conveyed completely through the apparatus for processing, then processing completeness is ensured, but processing time increases
Solution Approach 1:
The patent performs skew correction at an early stage in the conveyance path, before the sheet enters the main processing area. By correcting skew early and then quickly returning the sheet via reverse conveyance, the system ensures processing completeness while minimizing the time the sheet spends in conveyance, thereby improving overall productivity.
Data Source
AI summary
A sheet processing apparatus includes an entry portion, a sheet conveyance path extending from the entry portion, a skew correction roller pair that contacts a leading edge of a sheet conveyed in a predetermined direction from the entry portion to correct skew of the sheet, and a receiving path. The skew correction roller pair conveys the skew-corrected sheet in a direction opposite the predetermined direction. The receiving path branches from the sheet conveyance path from the entry portion to the skew correction roller pair to receive the sheet conveyed in the direction opposite the predetermined direction.