Sheet Conveyance Speed Synchronization to Prevent Bending
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Solution Overview
Problem
The existing sheet conveyance systems in image forming apparatuses face issues with sheet dispersion and increased load on drive units due to sheet bending, leading to reduced conveyance speed and increased torque requirements, which can result in larger and more costly apparatuses.
Innovation Solution
A sheet conveyance apparatus with dual units, where each unit has a conveyance unit, a drive unit, a detection unit, and a control unit, allowing independent control of conveyance speeds to synchronize sheet delivery and prevent bending, thereby maintaining optimal torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet conveyance speed is decreased to synchronize timing, then the sheet timing agrees with the transfer unit, but the sheet becomes deformed and bending occurs
Solution Approach 1:
The patent implements dynamic speed adjustment in the first conveyance unit based on real-time sheet detection. The control unit varies the conveyance speed of the first conveyance unit during sheet conveyance, while maintaining constant speed in the second conveyance unit. This dynamic adjustment allows timing synchronization without causing sheet deformation, as the speed change occurs in a controlled manner after the sheet has been properly fed.
Solution Approach 2:
The conveyance system is divided into two independent conveyance units with separate drive mechanisms. The first conveyance unit (in the feeding option) and the second conveyance unit (in the image forming apparatus main body) can be controlled independently. This segmentation allows the first unit to adjust its speed dynamically while the second unit maintains constant speed, resolving the contradiction between timing synchronization and sheet deformation.
2Reliability
If the sheet conveyance speed decreases due to deformation, then timing is corrected, but the load on the drive unit increases due to pushing force
Solution Approach 1:
The control unit dynamically adjusts the speed of the first conveyance unit during operation, increasing speed when sheets are delayed and decreasing speed when sheets are ahead. This dynamic control prevents sheet deformation and the associated pushing forces that would increase drive unit load, while still achieving proper timing synchronization at the transfer unit.
Solution Approach 2:
The detection unit continuously monitors sheet position and provides feedback to the control unit, which adjusts the first conveyance unit's speed accordingly. This closed-loop feedback system ensures timing synchronization is achieved without excessive drive unit load by making real-time adjustments based on actual sheet conveyance status.
3Power
If the torque is increased to handle sheet bending loads, then the drive unit can maintain operation, but the apparatus size and cost increase
Solution Approach 1:
Instead of designing the drive unit with excessive torque capability to handle sheet bending loads, the patent uses dynamic speed adjustment to prevent bending from occurring in the first place. The first conveyance unit's speed is continuously adjusted to maintain proper sheet timing, eliminating the need for oversized drive units with high torque margins. This results in a more compact and cost-effective apparatus design.
Data Source
AI summary
A sheet conveyance apparatus conveys a sheet without imposing a load on a drive unit due to the bend of the sheet when the sheet is conveyed from one unit to the other, and when the sheet is conveyed by a second conveyance unit and a first conveyance unit, a first control unit controls a first drive motor and a second control unit controls a second drive motor to make a sheet conveyance speed of the first conveyance unit equal to or higher than that of the second conveyance unit.