Sheet Feeding Unit One-Way Clutch Loop Elimination
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Solution Overview
Problem
Image forming apparatuses with bent sheet feeding paths experience burst sounds and uneven abrasion due to loop formation and backward tension when using one rotation control, which affects the feeding rollers and conveying rollers.
Innovation Solution
A sheet feeding unit with a feeding roller, drive motor, and conveying roller set to higher conveyance speed, combined with a one-way rotation control mechanism that stops driving force transmission when the feeding roller is pulled, preventing loop elimination and reducing unnecessary load on rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the conveying roller conveys the sheet at a speed higher than the feeding roller feeds the sheet, then the loop of the sheet is eliminated, but the feeding roller is pulled by the conveyed sheet and backward tension is applied causing burst sounds and uneven abrasion
Solution Approach 1:
The patent makes the driving force transmission mechanism dynamic by introducing a one-way clutch that automatically engages or disengages based on the rotational direction and speed of the feeding roller. When the feeding roller rotates faster than the conveying roller (causing backward tension), the one-way clutch disengages to stop driving force transmission, thereby eliminating burst sounds and uneven abrasion while maintaining loop elimination benefits.
Solution Approach 2:
The one-way clutch acts as an intermediary between the drive motor and the feeding roller. It mediates the transmission of driving force by allowing power transmission in the normal rotation direction but blocking it when the feeding roller rotates in reverse or faster than the conveying roller, thus preventing harmful backward tension without directly modifying the roller speeds.
2Ease of operation
If one rotation control of the feeding roller is employed, then the sheet is fed by 360-degree rotation, but the loop formed in the bent sheet feeding path is not eliminated and burst sounds occur when feeding is finished
Solution Approach 1:
The system uses speed comparison feedback between the feeding roller and conveying roller to control the driving force transmission. When the feeding roller's rotation speed exceeds that of the conveying roller (indicating loop formation), the one-way clutch automatically disengages, providing feedback-based control that prevents burst sounds while maintaining one rotation control functionality.
3Shape
If the feeding roller speed is set lower than the conveying roller speed, then loop is eliminated, but the feeding roller is pulled by the conveyed sheet applying load to both rollers causing uneven abrasion
Solution Approach 1:
The patent dynamically controls the driving force transmission based on the relative speeds of the feeding and conveying rollers. By using a one-way clutch that engages only when the feeding roller rotates slower than the conveying roller, the system maintains loop elimination while preventing the feeding roller from being pulled backward, thus avoiding uneven abrasion and improving roller reliability.
Data Source
AI summary
A feeding roller, a drive motor configured to drive the feeding roller, a control unit configured to perform one rotation control on the feeding roller, a sheet feeding path curved immediately after the feeding roller, a conveying roller pair provided in the sheet feeding path, and being set to a sheet conveyance speed higher than that of the feeding roller so as to eliminate a loop formed when a sheet passes through the sheet feeding path during one rotation control of the feeding roller; and a ratchet mechanism configured to stop the driving force from the drive motor and cause the feeding roller to be rotated by the sheet conveyed by the conveying roller pair when the feeding roller is pulled by the sheet being conveyed by the conveying roller pair in the course of the one rotation control of the feeding roller are provided.