Color Registration Error Correction in Multi-Pass Image Forming
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Solution Overview
Problem
In multi-pass type color image forming apparatuses, color registration errors occur due to changes in the rotational velocity of the intermediate transfer belt caused by contact with the cleaning unit, leading to misalignment of developing agent images.
Innovation Solution
A controller adjusts the exposure time points of subsequent color developing agent images to be earlier than that of the first color, and reduces the motor velocity in the exposure section to correct color registration errors, using equations to calculate the necessary adjustments based on the rotational time of the intermediate transfer belt and cleaning load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning unit contacts the intermediate transfer belt to remove developing agent wastes, then the cleaning function is achieved, but the rotational velocity of the intermediate transfer belt changes causing color registration errors
Solution Approach 1:
The control unit提前 adjusts the exposure time points of developing agent images based on the detected cleaning unit position. By calculating the expected velocity change and compensating in advance, the system prevents color registration errors before they occur, rather than correcting them after the cleaning action affects the transfer belt velocity
Solution Approach 2:
The system dynamically changes the exposure time point parameter based on the cleaning unit's contact with the intermediate transfer belt. By adjusting the timing parameter of the exposure unit in response to cleaning operations, the system compensates for velocity-induced position shifts and maintains color registration accuracy
2Ease of manufacture
If the cleaning blade contacts the intermediate transfer belt to clean developing agent wastes, then the intermediate transfer belt is cleaned, but friction causes rotational velocity decrease and color registration errors
Solution Approach 1:
The position sensing unit continuously monitors the intermediate transfer belt position and provides feedback to the control unit. When the cleaning unit contact is detected through position changes, the control unit receives real-time information and adjusts exposure timing accordingly, creating a closed-loop control system that maintains color registration despite velocity fluctuations
Solution Approach 2:
The control unit determines the exposure time point of developing agent images before the cleaning operation completes. By establishing the exposure timing in advance based on predicted velocity changes, the system ensures accurate color registration even as the cleaning blade affects transfer belt velocity during the process
Data Source
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AI summary
multi pass type color image forming apparatus and control method are provided. The apparatus advances an exposure time point of forming electrostatic latent images of second and subsequent colors more than that of a first color of a page during consecutive printing or reduces the velocity of a motor to rotate an intermediate transfer belt to minimize a color registration error between a developing agent image of the first color and developing agent images of the subsequent colors of the page caused by cleaning of the intermediate transfer belt and a control method thereof.