Image Forming Apparatus Sheet Separation Mechanism
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Solution Overview
Problem
Existing image forming apparatuses without a pickup roller often face issues with sheet jam removal and crease generation due to the lack of a reverse rotation mechanism, leading to potential sheet tearing and crease formation during multi-feed operations.
Innovation Solution
The apparatus incorporates a sheet separating rotary body with a rotation adjusting unit and a load resistance applying mechanism, allowing for controlled sheet separation and feed without a reverse rotation driving force, and includes a one-way clutch to prevent crease formation in subsequent sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sheet feed roller functions as both pickup roller and feed roller without a separate pickup roller, then cost is reduced, but sheet separation reliability deteriorates and multi-feed problems occur
Solution Approach 1:
The sheet feed roller is divided into two functionally independent parts: a pickup roller portion with high friction coefficient material for reliable sheet pickup, and a feed roller portion for sheet conveyance. This segmentation allows each part to optimize its function independently, maintaining sheet separation reliability while avoiding the need for a separate pickup roller assembly.
Solution Approach 2:
Different portions of the sheet feed roller are given different surface properties: the pickup portion uses high friction coefficient material to grip the sheet, while the feed portion has different characteristics for smooth conveyance. This local quality differentiation enables the single roller to perform both pickup and feeding functions effectively.
2Productivity
If the sheet separating roller rotates continuously to follow the sheet feed roller, then sheet feeding is smooth, but subsequent sheets become creased or folded
Solution Approach 1:
The sheet separating roller's rotation is made dynamic rather than continuous: it rotates only when a single sheet is being fed, and stops when multiple sheets are detected. This dynamic control prevents subsequent sheets from being creased while maintaining smooth feeding during single-sheet operation.
Solution Approach 2:
The system uses feedback from sheet detection to control the sheet separating roller's rotation. When multiple sheets are detected in the sheet separation nip region, the roller stops rotating; when a single sheet is detected, the roller rotates to follow the sheet feed roller. This feedback control prevents sheet creasing while maintaining feeding efficiency.
3Ease of operation
If the sheet container is slidably detached from the apparatus body for jam removal, then access to jammed sheets is improved, but device complexity increases
Solution Approach 1:
The sheet separation roller is designed to be detachable along with the sheet container, allowing users to easily remove both components together to access and remove jammed sheets. This self-service design simplifies the overall detachment mechanism while improving jam removal accessibility.
Data Source
AI summary
An image forming apparatus includes an apparatus body, a sheet container, an image forming part to form an image, a sheet feeding rotary body to feed the recording medium, a sheet separating rotary body to contact the sheet feeding rotary body and rotate with the sheet feeding rotary body with a sheet separation nip region formed therebetween, a rotation adjusting unit to adjust rotation of the sheet separating rotary body, a sheet containing unit to contain the recording media therein, a sheet separating body storing unit disposed at one end of the sheet containing unit to store the sheet separating body therein, and a load resistance applying mechanism to apply a rotational load resistance different from a contact force generated by contacting of the sheet separating rotary body with the sheet feeding rotary body, to the sheet feeding rotary body with no rotation driving force applied thereto.