Image Forming Apparatus Jam Recovery Sheet Detection
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately determining if all sheets have been ejected after a jam, leading to potential re-jams due to undetected remaining sheets, and require wasteful use of examination sheets to verify the conveyance path status.
Innovation Solution
An image forming apparatus with a control unit that stores information on confirmed sections of the conveyance path free of remaining sheets, allowing regular sheet feeding only after confirming these sections, thus avoiding unnecessary sheet wastage and minimizing recovery time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an examination sheet is used to travel through the conveyance path to check for remaining sheets after automatic purge, then the presence of remaining sheets can be detected, but sheets are wasted and recovery time is delayed
Solution Approach 1:
The first sheet after recovery serves dual purposes: it is both the initial processing sheet and the examination sheet that detects remaining sheets in the conveyance path. The sheet detectors monitor this sheet's passage to confirm the conveyance path is clear, eliminating the need for separate examination sheets.
Solution Approach 2:
The first sheet performs multiple functions simultaneously: it undergoes normal image formation processing while also serving as the examination sheet to verify the conveyance path status. This multi-functionality reduces sheet consumption and accelerates recovery.
2Measurement precision
If an examination sheet is used to verify the conveyance path status, then remaining sheets can be detected, but the recovery time from jam is increased
Solution Approach 1:
The examination function is integrated into the continuous sheet feeding process. The first sheet continues its normal journey through the conveyance path while simultaneously serving as the examination sheet, maintaining continuous useful action without interruption for separate examination.
Solution Approach 2:
The first sheet performs self-examination by passing through the conveyance path under monitoring of sheet detectors, eliminating the need for separate examination sheets and reducing recovery time.
3Extent of automation
If sensors are disposed on the conveyance path to detect sheets, then sheet presence can be monitored, but sheets between sensors cannot be detected leading to false recognition of purge completion
Solution Approach 1:
The first sheet acts as an intermediary that physically bridges the gaps between sensors. As it passes through the conveyance path, it triggers sensors at multiple points, providing continuous verification that the path is clear, including sections that would otherwise be undetectable.
Solution Approach 2:
The conveyance path is divided into multiple detection zones by several sheet detectors positioned at different locations. Each detector monitors a specific segment, and the combination of all detector signals provides comprehensive coverage of the entire path, eliminating blind spots.
Data Source
AI summary
An image forming apparatus includes a sheet feeding unit; an image forming unit; a conveying unit; sheet detectors disposed on a conveyance path to detect a sheet; a sheet ejection unit which, if a jam occurs on the conveyance path, ejects a remaining sheet on the conveyance path after a sheet that has caused the jam is removed; and a control unit which stores, in a storage unit, information representing a confirmed section of the conveyance path, the confirmed section being a section confirmed to have no remaining sheet as a result of ejection of the remaining sheet, and which, if one of the sheet detectors detects a first sheet that has reached the confirmed section after recovery from the jam, allows the sheet feeding unit to feed second and subsequent sheets.