Sheet Processing Apparatus Roller Timing Control
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Solution Overview
Problem
Conventional sheet processing apparatuses lack a lower guide for guiding sheets to the pressure contact part of the discharge roller pair, leading to issues with smooth discharge, especially when the front end of the sheet collides with the circumferential surface of the discharge roller pair, depending on the sheet conveyance condition or type.
Innovation Solution
A sheet processing apparatus with a discharge roller pair composed of first and second rollers, where the second roller is movable between a pressure contact and retracting position, and a pressure contact/separation mechanism that adjusts the timing of the second roller's pressure contact based on the sheet type to prevent collisions during discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sheet is made to fall onto the processing tray without a lower guide, then the device structure is simplified, but the sheet discharge smoothness deteriorates due to collision with the discharge roller pair
Solution Approach 1:
The lower guide is positioned in advance to guide the sheet toward the pressure contact part of the discharge roller pair before the sheet reaches the discharge point. This preliminary guidance prevents collision with the discharge roller pair and ensures smooth discharge without requiring complex additional structures.
2Reliability
If the discharge roller pair is kept in pressure contact state, then sheet discharge is ensured, but sheet collision with the roller surface occurs for certain sheet types
Solution Approach 1:
The lower guide provides localized guidance only at the critical area where the sheet approaches the pressure contact part of the discharge roller pair. This localized intervention is sufficient to prevent collision for specific sheet types without requiring the entire discharge system to be modified or the pressure contact state to be changed.
Data Source
AI summary
A sheet processing apparatus for processing sheets includes: a stack tray on which a sheet is stacked; a discharge roller pair composed of first and second rollers and configured to discharge a sheet onto the stack tray, the second roller being configured to be movable between a pressure contact position to contact with the first roller and a retracting position to separate from the first roller; and a pressure contact/separation mechanism for moving the second roller from the retracting position to the pressure contact position. The pressure contact/separation mechanism changes the timing at which the second roller reaches the pressure contact position according to the type of a sheet to be discharged.