Sheet Post-Processing Device Punch Hole Formation
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Solution Overview
Problem
Conventional paper sheet post-processing devices cannot efficiently form punch holes along the conveyance direction of A4-size paper sheets without stopping the paper conveyance, which is necessary due to the increasing demand for space-saving image forming apparatuses that perform longitudinal conveyance of A4-size paper sheets.
Innovation Solution
A sheet post-processing device equipped with a punch hole forming device that creates punch holes along the side end edge parallel to the conveyance direction, utilizing a conveyance roller pair, ejection roller pair, stiffening member, and on-tray processing portion to manage sheet conveyance and stiffness, allowing for continuous processing and proper sheet alignment and ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If punch holes are formed through a paper sheet along its end edge in a conveyance direction, then productivity is improved, but temporarily stopping conveyance is required which impairs productivity
Solution Approach 1:
The sheet end position is detected in advance before the sheet reaches the punch hole forming device. Based on this preliminary detection, the punch hole forming device is positioned at the correct location beforehand, allowing continuous conveyance without stopping while ensuring accurate punch hole formation along the conveyance direction.
Solution Approach 2:
A sheet end detection unit provides real-time feedback about the sheet position during conveyance. This feedback enables the control unit to dynamically adjust the punch hole forming device position or timing, maintaining accurate punch hole placement while keeping the conveyance system running continuously without interruptions.
2Stability of the object's composition
If a stiffening member is used to prevent sheet curling, then sheet stability is improved, but subsequent sheet end parts are disposed more inwardly causing misalignment
Solution Approach 1:
The stiffening member is designed to provide localized stiffness only at specific regions of the sheet where needed for preventing curling, while leaving other regions flexible. This selective stiffening maintains sheet stability without causing excessive inward displacement of sheet end parts that would lead to misalignment during subsequent processing.
Solution Approach 2:
The stiffening member's engagement with the sheet is dynamically controlled - it applies stiffness when needed during conveyance and ejection, but can be retracted or adjusted to accommodate subsequent sheets. This dynamic adjustment allows the system to maintain sheet stability during critical operations while preventing misalignment of subsequent sheets.
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
Enables the formation of punch holes along the conveyance direction without stopping the paper sheet conveyance, improving processing efficiency and preventing misalignment or curling of subsequent sheets, while maintaining productivity and ensuring proper sheet ejection.
Implementation Method 1
The stiffening member comes in contact with a sheet nipped between the ejection roller pair and deforms the sheet in a sheet thickness direction to impart stiffness to the sheet
Implementation Method 2
the ejection roller pair nips the sheet, with the stiffening member imparting stiffness to the sheet, and then the ejection roller pair ejects the sheet on the ejection tray
Data Source
AI summary
A sheet post-processing device of the present disclosure is provided with a punch hole forming device, a processing tray, an ejection tray, a conveyance roller pair, an ejection roller pair, and a stiffening member. In a case where a sheet through which punch holes have been formed is to be ejected on the ejection tray without being subjected to post-processing on the processing tray, in a state where the stiffening member is retracted in a direction away from the sheet, the conveyance roller pair conveys the sheet until at least a tip end thereof reaches on the ejection tray.