Eccentric Rotary Encoder Phase Control for Sheet Conveyance
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Solution Overview
Problem
Conventional sheet conveyance systems face challenges in achieving high-accuracy conveyance due to eccentricity in rollers, which affects the rotation phase and resulting conveyance amount, leading to variations in sheet displacement.
Innovation Solution
A control apparatus comprising a motor, a driving body with an eccentric rotary encoder, a detector, and a controller that generates velocity data to specify the position-phase relation between the rotation position and phase of the driving body, allowing precise control of the conveyance roller and sheet displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an eccentric roller is used for sheet conveyance, then the conveyance system can operate, but the conveyance amount varies depending on rotation phase leading to low conveyance accuracy
Solution Approach 1:
The patent converts the harmful effect of roller eccentricity into a useful signal. By deliberately creating eccentricity between the encoder disk and encoder shaft, the system generates a periodic velocity component in the encoder output that directly indicates the rotation phase. This phase information is then used to correct conveyance measurements, transforming what would normally be a source of error into a corrective mechanism.
Solution Approach 2:
The system implements feedback by using the encoder to detect the actual rotation phase and conveyance amount, then comparing this with the target conveyance. The detected phase information feeds back into the control system to calculate correction amounts, which are applied to adjust subsequent conveyance operations, creating a closed-loop control system that continuously improves accuracy.
2Manufacturing precision
If a dedicated sensor is added to detect rotation phase for high-accuracy conveyance, then conveyance accuracy improves, but device complexity and production cost increase
Solution Approach 1:
The encoder serves multiple functions simultaneously: it measures the rotation amount for basic conveyance control and, through the intentional eccentricity arrangement, also detects the rotation phase. This multi-functionality eliminates the need for separate phase detection sensors, reducing system complexity while maintaining high conveyance accuracy.
Solution Approach 2:
The system makes the existing encoder serve the additional function of phase detection through clever mechanical arrangement (eccentricity). Rather than adding a dedicated phase sensor, the encoder's output signal is processed to extract phase information, allowing the single sensor to perform multiple measurement tasks and reducing overall system complexity.
3Loss of information
If the encoder disk is positioned concentrically with the encoder shaft, then the encoder structure is simple, but it cannot detect phase information needed for high-accuracy conveyance
Solution Approach 1:
The system separates the functions of rotation amount measurement and phase detection by creating two distinct rotational relationships: the encoder disk rotates with the roller, while the encoder shaft rotates at a different speed and phase. This segmentation allows each component to fulfill its specific measurement function independently, with the encoder capturing both conveyance amount and phase information through its dual rotational inputs.
4Manufacturing precision
If velocity data processing is performed to specify position-phase relation, then conveyance accuracy improves, but data processing complexity increases
Solution Approach 1:
The system performs preliminary processing of the encoder output data to extract the periodic velocity component and determine the position-phase relationship before actual conveyance control. By pre-calculating the correction amounts and storing the phase information, the system reduces the computational burden during real-time operation, making the control process more manageable despite the increased accuracy requirements.
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 solution enables high-accuracy control of the conveyance roller and sheet displacement, reducing the need for dedicated sensors and lowering production costs while ensuring precise alignment and conveyance accuracy.
Implementation Method 1
a rotary encoder including a disk and a sensor, the disk being fixed to the driving body in a state of being eccentric to the rotational axis of the driving body
Data Source
AI summary
A control apparatus includes: a motor; a driving body rotated by the motor; a rotary encoder including a disk and a sensor; a detector detecting a rotation position and a rotation velocity of the disk based on a signal outputted from the sensor; and a controller. The disk is fixed to the driving body in a state of being eccentric to a rotational axis of the driving body, and the sensor reads a scale of the disk and outputs a pulse signal depending on rotation of the disk. The controller generates velocity data indicating a locus of the rotation velocity with respect to the rotation position; specifies a position-phase relation between the rotation position of the disk and a rotation phase of the driving body; and controls at least one of the rotation of the driving body and displacement of an object being displaced by action from the driving body.