Linear Encoder Slide Unit for Recording Medium Transfer Accuracy
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Solution Overview
Problem
Existing recording medium transfer apparatuses face challenges in accurately measuring transfer amounts due to factors like eccentricity of driving rollers, encoders, and variations in endless belt thickness, especially at longer transfer distances, leading to significant measurement errors.
Innovation Solution
A recording medium transfer apparatus with a slide unit that moves freely along a guide axis, engaging and disengaging with the endless belt, and utilizing a linear encoder to calculate the transfer amount, allowing for accurate measurement regardless of transfer distance, while minimizing the impact of belt eccentricity and thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If encoders are provided on the rotation axes of the driving rollers to control transfer amount by the number of pulses, then the transfer amount can be controlled, but measurement accuracy deteriorates due to eccentricity of driving rollers, encoder eccentricity, and variation in endless belt thickness especially at long transfer distances
Solution Approach 1:
The patent introduces a slide unit as an intermediary component that contacts the endless belt directly and moves along a guide axis. This slide unit serves as a mediator between the belt movement and the linear encoder, providing a stable reference point for measurement that is not affected by driving roller eccentricity or belt thickness variations. The linear encoder mounted on the stationary housing measures the position of this intermediary slide unit, thereby indirectly measuring the belt's actual movement with high precision.
Solution Approach 2:
The patent replaces the rotational encoder system (which measures rotation of driving rollers) with a linear encoder system (which measures linear displacement of the slide unit). This substitution eliminates the problems associated with rotational measurement including eccentricity effects and cumulative errors over long distances. The linear encoder provides direct measurement of the belt's actual movement along its path, significantly improving measurement accuracy.
2Productivity
If the transfer distance is extended to increase productivity, then more recording media can be processed, but measurement accuracy deteriorates due to accumulation of errors from eccentricity and belt thickness variation
Solution Approach 1:
The patent replaces the rotational encoder system with a linear encoder system that directly measures the belt's linear displacement. This substitution eliminates cumulative errors that occur in rotational systems over long distances, allowing accurate measurement even when the transfer distance is extended to increase productivity.
Solution Approach 2:
The slide unit creates a simplified copy or representation of the belt's movement by directly contacting and following its path. This copy mechanism (the slide unit moving along the guide axis) provides a clean, direct measurement reference that is independent of the complex rotational mechanics of the driving rollers, enabling accurate measurement over extended transfer distances.
3Measurement precision
If a linear encoder is used to measure the slide unit's position, then transfer amount measurement accuracy improves, but device complexity increases due to additional components
Solution Approach 1:
The slide unit acts as a simple intermediary that converts the complex rotational and flexing motion of the endless belt into simple linear motion along a guide axis. This intermediary mechanism is mechanically simple (essentially a block sliding on a rail) and when combined with the linear encoder, provides high-precision measurement without requiring complex rotational encoding systems.
Solution Approach 2:
The patent extracts the measurement function from the rotational driving system and places it on a separate, independent linear measurement system. By taking out the measurement function and implementing it through a dedicated slide unit with linear encoder, the system achieves high measurement accuracy while keeping the measurement subsystem simple and independent from the complex drive mechanics.
Data Source
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AI summary
A recording medium transfer apparatus is provided with: an endless belt; a plurality of transfer rollers, which intermittently rotate the endless belt; a sliding unit, which can freely reciprocate between the initial position and the terminal position of the endless belt; a drive device, which returns the sliding unit to the initial position from the terminal position; a linear encoder, which detects a moving quantity of the sliding unit; a calculating unit, which calculates a transfer quantity of the recording medium on the basis of the detection results obtained from the linear encoder; and a control unit, which controls the transfer quantity of the recording medium on the basis of the transfer quantity. The sliding unit engages with the endless belt at the initial position before the endless belt rotationally moves, then, moves with the rotational move of the endless belt, and when the sliding unit reaches the terminal position, the sliding unit releases the engagement with the endless belt, and returns to the initial position by means of the driving device when the endless belt is stopped. The calculating unit calculates the transfer quantity of the recording medium on the basis of the detection results obtained from the linear encoder, said detection results being the moving quantity of the sliding unit from the initial position to the terminal position.