Sheet Path Switching Timing for Jam-Resistant Image Forming
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Solution Overview
Problem
Existing image forming apparatuses face issues with delayed path switching operations due to abrasion of moving mechanisms, leading to potential sheet damage or jamming.
Innovation Solution
A sheet conveyance device with a switching member and a control unit that adjusts path switching based on the timing of the leading and trailing edges of sheets, ensuring timely path changes to prevent sheet damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switching member is moved using a mechanical moving mechanism, then the path switching function is achieved, but the switching operation is delayed due to abrasion of the moving mechanism
Solution Approach 1:
The control unit calculates the ideal switching timing in advance based on sheet conveyance speed and distance, and issues switching commands before the sheet actually reaches the switching point. This preliminary action compensates for the mechanical delay caused by abrasion in the moving mechanism, ensuring the switching member arrives at the correct position when needed.
Solution Approach 2:
The system uses sensors to detect the actual position of the switching member and the conveyance status of sheets, feeding this information back to the control unit. The control unit continuously adjusts the switching timing based on this feedback, compensating for variations in mechanical response due to wear and ensuring accurate path switching despite aging components.
2Ease of operation
If the switching member switches path based on upstream sensor detection, then the switching operation is simplified, but sheet damage or jam may occur due to late switching
Solution Approach 1:
Instead of waiting for the sheet to reach the switching point, the control unit calculates the required switching time in advance based on the sheet's conveyance speed and distance to the switching point. The switching command is issued preliminarily, allowing the switching member to move to the correct position before the sheet arrives, thus preventing sheet damage while maintaining simple control logic.
Solution Approach 2:
The system replaces purely mechanical position-based switching with a control system that uses calculated timing and electronic signals. The control unit determines switching timing based on conveyance speed and distance calculations, substituting the need for complex mechanical sensing and reaction systems, thereby preventing sheet damage while keeping the control system relatively simple.
3Device complexity
If the switching member operates with fixed timing, then the control system is simple, but it cannot adapt to variations in sheet conveyance speed
Solution Approach 1:
The switching timing is made dynamic rather than fixed. The control unit continuously calculates the optimal switching time based on the actual conveyance speed of each sheet, which may vary due to different paper types, sizes, or conveyance conditions. This dynamic adjustment ensures accurate switching while keeping the control system relatively simple by using basic speed and distance calculations.
Solution Approach 2:
The system changes the timing parameter dynamically based on conveyance speed variations. Instead of using a fixed switching time, the control unit adjusts the switching timing parameter according to the measured or estimated sheet conveyance speed, allowing the system to adapt to different operating conditions while maintaining a relatively simple control structure.
Data Source
AI summary
A sheet conveyance device includes first and second conveyance paths, a switching member, a moving mechanism, and a control unit, wherein when the control unit starts energization of a solenoid, the switching member is moved from a second position to a first position, wherein when the control unit stops energization of the solenoid, the switching member is moved from the first position to the second position, wherein a first timing is a timing earlier than a timing when a leading edge of a sheet reaches the switching member, and a second timing is a timing when a trailing edge of a preceding sheet passes through a position downstream of the switching member, and wherein in a case where the switching member is moved from the first position to the second position, the control unit stops energization of the solenoid at an earlier timing of the first and second timings.