Transfer Drum Grippers Prevent Recording Medium Sagging

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Solution Overview

Problem

Current image forming apparatuses face challenges in efficiently transferring and fixing toner images onto recording media, particularly in maintaining image quality and preventing defects like creases and smudging, due to limitations in gripping and rotating mechanisms for the recording medium.

Innovation Solution

The apparatus employs a transfer unit with a transfer drum, a leading-end gripper, and a trailing-end gripper that rotate in synchronization with the image carrying member, using an elastic layer and a pressing sheet to grip and transport the recording medium, ensuring precise image transfer and fixation by adjusting the grippers' positions and states to match the drum's rotation, thereby minimizing sagging and ensuring surface contact for defect-free image transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional sheet feeding mechanism is used, then the recording medium can be fed to the transfer position, but the recording medium sags between the sheet feeding position and the transfer position, causing creases and image defects

Engineering Contradiction:

Improveimage qualityVSAvoidsagging of recording medium

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The leading-end holding member grips the leading end of the recording medium in advance at the sheet feeding position, and the trailing-end holding member waits at a predetermined position downstream. This preliminary gripping action prevents the recording medium from sagging during transport to the transfer position, eliminating creases and image defects before they can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The leading-end and trailing-end holding members act as intermediary elements between the sheet feeding mechanism and the transfer position. These holding members provide continuous support to the recording medium during transport, preventing sagging without interfering with the image transfer process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the recording medium is held tightly during transport, then sagging is prevented, but the recording medium cannot be released smoothly after transfer, causing feeding errors

Engineering Contradiction:

Improvestable transport of recording mediumVSAvoidrelease of recording medium after transfer

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The leading-end holding member and trailing-end holding member are designed to dynamically adjust their gripping states. They grip the recording medium firmly during transport to prevent sagging, then automatically release it after transfer. The holding members rotate synchronously with the transfer member, enabling smooth transition between gripping and releasing states without causing feeding errors.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control unit monitors the position and state of the holding members relative to the transfer member, and adjusts their operation accordingly. This feedback mechanism ensures that the holding members release the recording medium at the correct moment after transfer, preventing feeding errors while maintaining stable transport during the critical transfer period.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the holding members rotate synchronously with the transfer member, then precise image transfer is achieved, but the device complexity increases

Engineering Contradiction:

Improveprecision of image transferVSAvoidsynchronization mechanism of holding members

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The leading-end holding member and trailing-end holding member are integrated with the transfer member structure, sharing the same rotation axis and synchronous motion. This merging of functions eliminates the need for separate synchronization mechanisms, reducing device complexity while maintaining precise image transfer through the natural synchronous rotation of the integrated structure.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8774688B2Image forming apparatus with leading-end and trailing-end holding members to prevent sagging of recording medium during transportation

Publication Date: 2014.07.08 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes an image carrying member, a transfer member, a leading-end holding member, and a trailing-end holding member. The leading-end holding member is mounted on the transfer member and holds, on an outer peripheral surface of the transfer member, a leading-end portion of a recording medium fed to a sheet feeding position that is further upstream than a transfer position in a rotation direction of the transfer member. The trailing-end holding member rotates along the outer peripheral surface. The trailing-end holding member presses the recording medium against the outer peripheral surface while waiting at a waiting position that is further upstream than the transfer position and downstream than the sheet feeding position, and holds a trailing end portion on the outer peripheral surface while rotating together with the transfer member when the trailing end portion of the recording medium arrives at the waiting position.