Image Forming Apparatus Jam Subsequent Sheet Ejection Control
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Solution Overview
Problem
Conventional image forming apparatuses face difficulties in effectively ejecting jam-subsequent paper sheets during pre-purge processing, especially when paper jams occur near the toner image transferring point, leading to secondary jams and image quality issues due to the lack of dedicated ejection paths for such sheets.
Innovation Solution
The image forming apparatus incorporates an abnormality detecting section to differentiate between primary and secondary abnormal states, controlling the conveyance and ejecting sections to halt the jam-causing paper sheet while continuing the conveyance of jam-subsequent sheets upstream, and utilizing multiple independent ejecting trays to manage paper sheets effectively during pre-purge processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conveyance operation is halted for all paper sheets when a paper jam occurs, then the primary abnormal state is addressed, but the productivity is reduced due to inability to continue processing other paper sheets
Solution Approach 1:
The patent segments the paper sheet handling into two distinct groups: jam-subsequent paper sheets (processed via pre-purge to specific tray) and other paper sheets (continuously conveyed). This segmentation allows selective continuation of conveyance operations for non-affected sheets while addressing the jam condition, thereby maintaining productivity without compromising jam handling reliability
Solution Approach 2:
The patent implements preliminary action by conducting pre-purge processing for jam-subsequent paper sheets before they can cause secondary jams or image quality issues. The control section identifies these sheets and directs them to a specific tray in advance, preventing potential problems before they occur while allowing other sheets to continue processing
2Productivity
If jam-subsequent paper sheets are continuously conveyed without halting, then the productivity is maintained, but secondary abnormal states occur causing image quality degradation
Solution Approach 1:
The control section performs preliminary identification and separation of jam-subsequent paper sheets before they can cause secondary abnormal states. By detecting the paper jam condition and identifying affected sheets in advance, the system directs them to a specific tray through pre-purge processing, preventing secondary jams and image quality issues before they occur
Solution Approach 2:
The patent introduces an intermediary control mechanism that monitors paper sheet conditions and intermediates between continuous conveyance and halting operations. The control section acts as a mediator by detecting abnormal states and selectively directing jam-subsequent sheets to a specific tray, allowing continuous processing of normal sheets while protecting image quality through targeted intervention
3Device complexity
If a single ejecting tray is used for all paper sheets, then the device complexity is reduced, but the ease of operation deteriorates due to inability to separately manage normal and jammed sheets
Solution Approach 1:
The patent segments the ejection function by designating a specific tray exclusively for jam-subsequent paper sheets while other trays handle normal sheets. This functional segmentation allows operators to easily identify and retrieve jam-affected sheets without mixing them with normal output, improving ease of operation with minimal additional complexity
Solution Approach 2:
The patent applies local quality by assigning different functions to different trays: the specific tray is dedicated to jam-subsequent sheets requiring special handling, while other trays maintain their normal ejection function. This localized functional differentiation improves operational convenience by providing clear separation of sheet types without requiring complete system redesign
Data Source
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AI summary
Disclosed is an image forming system, which makes it possible to effectively eject the jam-subsequent paper sheet remaining therein. In the system, a primary abnormal state in which the conveyance operation cannot be continued, and a secondary abnormal state in which an adverse influence is possibly incurred to the image formed on the paper sheet though it is possible to continue the conveyance operation, are defined. In the state that the primary abnormal state or the secondary abnormal state is detected in midcourse of the conveyance operation, when a pre-purge processing for conveying the jamsubsequent paper sheet is implemented so as to eject the jam-subsequent paper sheet onto the ejecting tray, controlling operations are conducted so as to continue the conveyance operation without halting the conveyance operation, even if the secondary abnormal state in respect to the jam-subsequent paper sheet is detected in midcourse of performing the pre-purge processing thereof