Transfer Member Contact Speed Control for Image Quality
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Solution Overview
Problem
Electrophotographic image forming apparatuses experience shock jitter due to the impact of recording media on the image bearer, leading to image distortion, and existing solutions for preventing this issue are uneven and dependent on the thickness of the recording medium.
Innovation Solution
An image forming apparatus with a contact-and-separation device that adjusts the speed of the transfer member's contact and separation based on the thickness of the recording medium, ensuring stable image transfer by controlling the contact-and-separation operations to minimize shock jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the transfer member is brought into contact with the image bearer as the recording medium passes between them to prevent shock jitter, then image distortion is reduced, but uneven performance occurs with respect to prevention of shock jitter varying with the thicknesses of the recording media used
Solution Approach 1:
The contact-and-separation device dynamically adjusts the timing and duration of contact between the transfer member and image bearer based on recording medium thickness. The control unit varies the contact timing relative to the leading end position and trailing end position of the recording medium, creating a dynamic system that adapts to different thicknesses rather than using a fixed contact pattern.
Solution Approach 2:
The system changes the contact parameters (timing and duration) of the transfer member based on the thickness parameter of the recording medium. By adjusting when the transfer member contacts the image bearer relative to the recording medium's leading and trailing ends, the system optimizes shock jitter prevention for each thickness category.
2Object-affected harmful factors
If the transfer member remains in constant contact with the image bearer, then shock jitter is reduced, but image distortion occurs due to impact when the recording medium enters and exits
Solution Approach 1:
The contact-and-separation device implements periodic contact and separation actions rather than constant contact. The transfer member is brought into contact with the image bearer during the period when the recording medium is passing through (between leading end entry and trailing end exit), and separated during other periods. This periodic action reduces shock jitter while preventing impact-related image distortion.
Solution Approach 2:
The control unit initiates the contact operation before the recording medium completely enters or exits the transfer nip, and terminates it before impact occurs. By timing the contact to start and end at appropriate moments during the recording medium passage, the system prevents the harmful impact that would occur with constant contact while still providing shock jitter reduction during the critical transfer period.
Data Source
AI summary
An image forming apparatus includes an image bearer, an image forming device, a transfer member, and a contact-and-separation device. The contact-and-separation device starts a contact operation to move the transfer member to contact the image bearer according to an entry of a recording medium into a transfer nip. The thinner the recording medium, the faster a contacting speed at which the transfer member moves to contact the image bearer. The thicker the recording medium, the slower the contacting speed.