Sheet Processing Press Unit and Grasping Mechanism for Fold Line Quality
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Solution Overview
Problem
Existing sheet processing apparatuses face issues with maintaining the appearance quality of fold lines in saddle-stitched and mid-folded sheet bundles, as pressing can cause the outermost sheet to rip, and reducing pressure compromises the fold line's appearance.
Innovation Solution
A sheet processing apparatus with a press unit that presses the fold line from a direction perpendicular to the front page surface, accompanied by a grasping unit that switches between grasping and releasing the sheet bundle based on the number of sheets to prevent ripping and maintain productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the press roller applies pressure to the fold line portion, then the appearance quality of the fold line is improved, but the outermost sheet (cover) is pulled and may be ripped
Solution Approach 1:
A grasping unit is introduced as an intermediary component between the press roller and the sheet bundle. This grasping unit selectively grasps the sheet bundle during pressing operations to prevent the cover from being pulled, while allowing the press roller to apply necessary pressure to the fold line portion without causing sheet ripping
2Object-affected harmful factors
If the pressing force of the press roller is reduced to prevent cover ripping, then sheet ripping is prevented, but the appearance quality of the fold line portion cannot be maintained
Solution Approach 1:
The grasping unit serves as a mediator that enables the press roller to apply full pressing force to the fold line while preventing the cover from being pulled. By selectively grasping the sheet bundle, the grasping unit allows necessary pressure to be applied without causing sheet ripping, thus maintaining both appearance quality and preventing harm
3Object-affected harmful factors
If a grasping unit is added to prevent cover ripping, then sheet ripping is prevented, but the device complexity increases
Solution Approach 1:
The grasping unit is merged with the existing conveyance unit structure, sharing common components such as the conveyance path and positioning mechanisms. This integration approach allows the grasping functionality to be added while minimizing increases in overall device complexity by reusing existing structural elements
Data Source
AI summary
A sheet processing apparatus includes a sheet stacking unit, a binding unit, a folding unit, a conveyance unit, a press unit, a grasping unit, and a control unit. The binding unit performs binding processing on a sheet bundle stacked in the sheet stacking unit. The conveyance unit conveys a sheet bundle folded by the folding unit. The press unit presses a fold line portion of the conveyed sheet bundle from a direction perpendicular to a surface of a front page of the sheet bundle while moving along the fold line portion. The grasping unit is switched between a first state in which the grasping unit fixes the sheet bundle in position and a second state in which the grasping unit does not grasp the conveyed sheet bundle. The control unit shifts the grasping unit to the first state and causes the press unit to press the sheet bundle.