Transfer Roller Velocity Control for Image Alignment
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Solution Overview
Problem
Image forming apparatuses face issues with image quality degradation and misalignment due to fluctuations in the circumferential velocity of the intermediate transfer belt and sheet transporting velocity, particularly when the transfer roller and intermediate transfer belt come into contact or separate, causing significant impact and misalignment of toner images.
Innovation Solution
An image forming apparatus with a torque limiter in the drive mechanism that adjusts the rotational velocity of the secondary transfer roller relative to the intermediate transfer belt, ensuring it rotates at a lower velocity when separating and a higher velocity when contacting, to minimize impact and maintain constant image transfer velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transfer roller is brought into contact with the intermediate transfer belt at a velocity faster than that of the intermediate transfer belt, then the torque limiter slips to maintain constant velocity of the intermediate transfer belt, but enormous impact is applied from the transfer roller to the intermediate transfer belt causing significant degradation of image quality
Solution Approach 1:
The system performs preliminary velocity adjustment by driving the transfer roller at a lower velocity before contact with the intermediate transfer belt. This preliminary action ensures that when contact occurs, the velocity difference is minimized, thereby reducing impact while still allowing the torque limiter to function properly for constant velocity maintenance during contact.
Solution Approach 2:
The system dynamically adjusts the rotational velocity of the transfer roller based on its contact state with the intermediate transfer belt. When separate, it rotates at a lower velocity; when in contact, it rotates at a higher velocity. This dynamic adjustment optimizes both impact reduction during contact and velocity maintenance through torque limiter slippage.
2Productivity
If the transfer roller and intermediate transfer belt come into contact or separate, then image transfer can be performed, but impact is applied to the intermediate transfer belt causing misalignment of toner images
Solution Approach 1:
Before the transfer roller comes into contact with the intermediate transfer belt for image transfer, the system preliminarily adjusts the rotational velocity of the transfer roller to be lower than that of the intermediate transfer belt. This preliminary velocity adjustment ensures that when contact occurs, the impact is minimized, thereby preventing toner image misalignment while still enabling image transfer functionality.
3Reliability
If the velocity of the intermediate transfer belt is maintained constant, then image quality degradation due to position deviation is prevented, but the contact/separate mechanism causes velocity fluctuation
Solution Approach 1:
The system implements dynamic velocity control for the transfer roller based on contact state. When separate from the intermediate transfer belt, the transfer roller rotates at a lower velocity to prevent velocity fluctuation and maintain belt stability. When in contact, it rotates at a higher velocity to enable the torque limiter mechanism to function, thereby maintaining constant intermediate transfer belt velocity and preventing image quality degradation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the impact on the intermediate transfer belt during contact and separation, preventing image misalignment and maintaining consistent image quality by synchronizing the velocities of the intermediate transfer belt and sheet, thus enhancing duplex printing accuracy.
Implementation Method 1
a torque limit unit disposed on a drive mechanism configured to transmit drive force to rotate the transfer unit, and configured to transmit drive force to the transfer unit at a torque less than a torque for transmitting drive force
Implementation Method 2
the transfer roller is brought into contact with the intermediate transfer belt at the velocity faster than the velocity of the intermediate transfer belt, which causes the torque limiter to slip
Data Source
AI summary
An image forming apparatus includes an image carrier, a transfer unit to transfer the image onto a recording medium, a torque limit unit to transmit drive force to the transfer unit at a torque less than the torque for transmitting drive force, and drive the transfer unit to rotate at a circumferential velocity higher than that of the image carrier when the image carrier and the transfer unit are in contact with each other, and a drive unit to output drive force to drive the transfer unit such that the transfer unit rotates at a circumferential velocity lower than that of the image carrier when the image carrier and the transfer unit are separate from each other, and the transfer unit rotates at a circumferential velocity higher than that of the image carrier when the image carrier and the transfer unit are in contact with each other.