Sheet Conveyance Purge Control for Compact Image Forming Systems
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Solution Overview
Problem
Medium- and small-sized image forming systems face challenges in implementing a purging function within sheet conveyance devices due to space constraints and the risk of sheets coming into contact during duplex printing, which limits their ability to efficiently manage jams and maintain reduced system size.
Innovation Solution
A sheet conveyance device with a body, conveyance unit, switching unit, delivery unit, reverse unit, return unit, and controller unit that allows sheets to be purged through the reverse slot without contact by controlling the switching and conveyance paths based on conditions such as the presence of other sheets, ensuring safe ejection and maintaining system compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the purging function is implemented in medium- and small-sized image forming systems, then sheet ejection capability is improved, but system size increases
Solution Approach 1:
The reverse slot is designed to serve dual purposes: as a reversing destination during duplex printing and as a purging destination for ejecting sheets. By making the reverse slot multi-functional, the patent enables sheet ejection capability without requiring additional dedicated purging space, thus avoiding system size expansion while maintaining operational capability.
Solution Approach 2:
The patent merges the purging function with the existing reverse slot structure by connecting the purging path to the reverse slot. This integration allows sheets to be ejected through the reverse slot alongside their normal reversing operation, combining two functions into one structural element and eliminating the need for separate purging space.
2Productivity
If sheets are purged through the reverse slot, then purging efficiency is improved, but sheet contact risk increases
Solution Approach 1:
The controller determines whether to purge sheets through the reverse slot based on advance detection of sheet presence in the reverse slot. By checking the state of the reverse slot before initiating purging, the system can prevent purging operations that would cause sheet contact, thus maintaining reliability while enabling efficient purging when safe.
Solution Approach 2:
The system uses feedback from sheet detection mechanisms to monitor the presence of sheets in the reverse slot and adjust purging operations accordingly. This feedback mechanism allows the controller to make real-time decisions about whether to proceed with purging through the reverse slot, preventing sheet contact while maintaining purging efficiency when conditions are favorable.
3Productivity
If spacing between sheets is reduced for higher productivity, then processing speed is improved, but sheet contact risk during purging increases
Solution Approach 1:
The controller performs preliminary detection of sheet spacing and reverse slot occupancy before initiating purging operations. This advance checking allows the system to account for reduced sheet spacing in duplex printing and only proceed with purging when it will not cause contact, thus maintaining high productivity while ensuring reliability.
Solution Approach 2:
The system dynamically adjusts purging decisions based on real-time conditions including sheet spacing and reverse slot occupancy. This dynamic control allows the system to optimize for productivity when conditions permit reduced spacing while automatically preventing purging operations that would cause contact, adapting to varying operational states.
Data Source
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AI summary
When a jam (JM) is detected in a post-processing device (150), a purge controller (402) first makes a conveyance roller group (11, 12P, etc.) and a reverse roller (45) continue conveyance. The purge controller then sets the conveyance destination of a leading sheet that will first arrive at a branch point (BP) after the time of detection of the jam. When a first condition is satisfied the purge controller sets the conveyance destination to a reverse slot (44), and when a second condition is satisfied the purge controller sets the conveyance destination to an outlet path (43, 140, 150). The first condition is satisfied when no other sheet is present in the reverse slot at the time of detection of the jam, and the second condition is satisfied when another sheet is present in the reverse slot at the time of detection of the jam.