Cam-Controlled Transfer Roller Spacing Mechanism
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Solution Overview
Problem
Conventional image forming apparatuses experience productivity losses and vibration issues during image adjusting sequences due to abrupt torque fluctuations when spacing the secondary transfer outer roller, leading to potential contamination and increased costs from required cleaning devices.
Innovation Solution
An image forming apparatus with a contact-and-separation mechanism that includes an urging member, a movement driving portion, and a controller to position the transfer member at specific contact and spaced positions, minimizing load fluctuations and vibrations, thereby maintaining productivity and avoiding contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the secondary transfer outer roller is spaced from the intermediary transfer belt during image adjusting sequence, then contamination of the roller is avoided, but vibration is generated due to abrupt torque fluctuation
Solution Approach 1:
The cam is pre-positioned at a specific phase where the urging force of the compression spring acts along the rotational axis rather than creating torque. This preliminary positioning ensures that when the roller is spaced during image adjusting sequence, no abrupt torque fluctuation occurs, thus preventing vibration while maintaining contamination prevention
Solution Approach 2:
The cam mechanism acts as an intermediary between the compression spring and the secondary transfer outer roller. By designing the cam with a specific phase position, it mediates the urging force to eliminate torque fluctuation during spacing operation, thereby resolving the contradiction between preventing contamination and avoiding vibration
2Ease of operation
If the cam is rotated to space the secondary transfer outer roller completely against the urging force, then the roller is fully spaced, but abrupt load fluctuation is generated
Solution Approach 1:
The cam is designed with a specific local phase position where the urging force vector aligns with the rotational axis. This local quality change in the cam geometry ensures that spacing operation can be performed without generating abrupt load fluctuation, maintaining both ease of operation and productivity
3Productivity
If the secondary transfer outer roller remains contacted to the intermediary transfer belt, then image formation continues without interruption, but the roller becomes contaminated with patch toner
Solution Approach 1:
The cam is pre-positioned at a specific phase that eliminates torque fluctuation during spacing. This preliminary action enables the system to quickly space the roller during image adjusting sequence and quickly return it to contact position afterward, minimizing interruption to continuous image formation while preventing contamination
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
The solution effectively suppresses vibrations and productivity losses during image adjusting sequences, reducing the need for cleaning devices and maintaining image quality, while preventing transfer member contamination.
Implementation Method 1
a structure in which the secondary transfer outer roller is spaced from the intermediary transfer belt by an urging force of a compression spring acting on a cam
Implementation Method 2
the cam has been rotated conventionally, until a patch where a rotational load torque of the cam by the urging force of the compression spring is eliminated
Data Source
AI summary
An image forming apparatus includes an image bearing member, a transfer member configured to transfer a toner image formed on the image bearing member onto a recording material, and a contact-and-separation unit configured to move the transfer member to a contact position where the transfer member contacts the image bearing member and a spacing position where the transfer member is separated from the image bearing member. A control portion controls a driving unit when the transfer member is moved from the contact position to the spacing position by using a phase range and a rotational direction of a cam of the contact-and-separation unit, in which a distance between an outer circumference at an abutted portion of a supporting member and a rotation center of the cam continuously increases with rotation of the cam.