Sheet Carrying Device With One-Way Clutch and Torque Limiter
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Solution Overview
Problem
Electrophotographic document printers face challenges in maintaining consistent sheet carrying speed due to variations in toner adhesion, environmental changes, and roller wear, leading to registration errors and image banding issues, which existing torque limiter systems struggle to stabilize effectively.
Innovation Solution
A sheet carrying device with a dual carrying unit system, incorporating a one-way clutch and torque limiter mechanisms, ensures synchronized peripheral speeds of the driving roller, photoreceptor drum, and transferring roller, maintaining a constant sheet carrying speed by adjusting the driving force transmission and torque limits to compensate for variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque limiter is provided in the driving mechanism of the driving roller to cut off driving force by slippage, then the influence of the driving roller on sheet carrying speed is reduced, but the carrying speed still varies due to changes in friction coefficient, environmental conditions, and roller wear
Solution Approach 1:
A friction member is introduced as an intermediary element between the driving roller and the sheet. This friction member has a larger contact area with the sheet than the driving roller, creating a buffer zone that absorbs speed variations. The friction member acts as a mediator that decouples the direct transmission of speed variations from the driving roller to the sheet, thereby stabilizing the carrying speed during toner transfer.
Solution Approach 2:
The invention changes the physical parameters of the driving system by introducing a friction member with specific material properties and a larger contact area. This parameter change transforms the driving mechanism from direct roller-to-sheet contact to a multi-element system where the friction member's properties (contact area, material friction characteristics) can be optimized to maintain stable sheet carrying speed despite variations in driving roller conditions.
2Manufacturing precision
If the carrying speed is determined by the peripheral speeds of multiple rollers, then the sheet can be carried through the toner transfer unit, but any variation in these speeds causes image expansion and contraction leading to banding
Solution Approach 1:
The friction member serves as an intermediary that decouples the speed control from the multiple rollers. Instead of relying on precise synchronization of driving roller, photoreceptor drum, and transferring roller peripheral speeds, the friction member absorbs speed variations and provides a stable interface for sheet carrying, thereby ensuring precise toner image transfer without banding.
Solution Approach 2:
The carrying mechanism is segmented into distinct functional zones: the driving roller provides initial propulsion, the friction member stabilizes the sheet and absorbs speed variations, and the photoreceptor drum and transferring roller complete the transfer. This segmentation allows each component to perform its specific function without requiring perfect synchronization of all components.
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
This configuration prevents image banding and enhances registration accuracy by maintaining a stable sheet carrying speed, even under environmental changes, thereby ensuring high-quality image formation.
Implementation Method 1
a one-way clutch and torque limiter mechanisms, ensures synchronized peripheral speeds of the driving roller, photoreceptor drum, and transferring roller
Implementation Method 2
a one-way clutch and torque limiter mechanisms, ensures synchronized peripheral speeds of the driving roller, photoreceptor drum, and transferring roller
Implementation Method 3
The sheet S is interposed between a driving roller 12 which is rotated by a motor 31 and a driving mechanism and a driven roller 11 which is rotated by contacting the driving roller 12
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A disclosed sheet carrying device includes a first carrying unit that includes a first rotary body, a first driving unit outputting a driving force at a first peripheral speed, a one-way clutch transmitting the driving force only in a sheet carrying direction, and a second rotary body driven by the first rotary body via the sheet; and a second carrying unit including a third rotary body rotating at a second peripheral speed being the first peripheral speed or more, a fourth rotary body carrying the sheet with the third rotary body, a second driving unit outputting a driving force for driving the fourth rotary body at a third peripheral speed being the second peripheral speed or more, and a torque limiter having a slip torque smaller than a sheet carrying torque and cutting off the driving force while the sheet is interposed between the third and fourth rotary bodies.