Tape Printer DC Motor Speed Correction
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Solution Overview
Problem
Conventional tape printers using DC motors for conveying printing media face challenges in maintaining constant rotational speed due to heat generation and load changes, leading to inaccuracies in print length and inability to adjust conveyance length, affecting the precision and quality of printing.
Innovation Solution
A tape printer system with a DC motor-driven conveyance mechanism, equipped with a detection device to measure drive time and a correction print cycle calculating unit, which adjusts the print cycle based on detected rotation, ensuring constant length printing by correcting the print cycle of the print head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a DC motor is used to drive the conveyance mechanism, then the device becomes low-cost and energy-efficient, but the rotational speed changes due to heat generation and load changes, causing printing inaccuracy
Solution Approach 1:
The patent employs an encoder to detect the rotational speed of the DC motor and feeds this information back to the control unit. The control unit then adjusts the print head drive signals based on the actual rotational speed, ensuring accurate printing despite variations caused by heat and load changes. This feedback mechanism resolves the contradiction by maintaining printing accuracy while using a cost-effective DC motor.
Solution Approach 2:
The patent dynamically changes the drive parameters of the print head based on the detected rotational speed of the DC motor. By adjusting the print cycle and drive signal parameters in real-time according to actual motor performance, the system maintains consistent printing accuracy despite changes in motor rotational speed due to thermal and load variations.
2Device complexity
If the rotational speed of the DC motor is determined by resistance values, then the system is simple to control, but the rotational speed changes with heat generation and load changes, making it difficult to maintain constant printing length
Solution Approach 1:
The encoder provides real-time feedback on the actual rotational speed to the control unit, which then adjusts the print head drive signals accordingly. This feedback loop compensates for speed variations caused by heat and load changes, maintaining consistent printing length without significantly increasing control system complexity.
Solution Approach 2:
The system performs preliminary detection of the DC motor's rotational speed using the encoder before and during the printing process. Based on this preliminary information, the control unit pre-adjusts or continuously adjusts the print head drive parameters to compensate for expected speed variations, ensuring consistent printing length.
3Manufacturing precision
If an encoder detects the rotational speed of the DC motor to maintain constant printing, then printing accuracy is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The encoder provides feedback on rotational speed to the control unit, which adjusts the print head drive signals accordingly. This feedback mechanism achieves accurate printing by compensating for motor speed variations, and while it increases device complexity, the benefits in printing accuracy justify the added complexity.
4Device complexity
If the print cycle is fixed, then the control system is simple, but the user cannot adjust the conveyance length to match different tape types
Solution Approach 1:
The patent makes the print cycle dynamic rather than fixed. The control unit adjusts the print cycle based on the detected rotational speed and user-selected tape type, allowing the system to adapt to different conveyance lengths. This dynamic adjustment capability provides versatility while maintaining relatively simple control through automated parameter modification.
Solution Approach 2:
The system changes the print cycle parameter dynamically based on detected motor speed and selected tape type. This parameter adjustment allows the same hardware system to accommodate different tape lengths and types, providing adaptability without requiring complex mechanical adjustments or multiple fixed systems.
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
The system achieves high-quality, constant-length printing by correcting the print cycle of the print head, even when the DC motor's rotational speed changes, reducing encoder resolution and control circuit load, and allowing user-adjustable tape length correction, thereby enhancing printing accuracy and reducing manufacturing costs.
Implementation Method 1
a tape conveyance mechanism having a DC motor as a drive source to convey a long tape
Implementation Method 2
a print head that performs printing dot-pattern data on the tape conveyed by the tape conveyance mechanism
Data Source
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AI summary
It is intended to provide a tape printer (1) and a tape creating method which can achieve a high degree of accuracy and constant length of printing even when the rotational speed of a DC motor (2) changes due to the increase of a wire wound resistance value because of the heat generation of the DC motor (2) under the continuous driving and the load change by the replacement of a tape (31). The print cycle algebra (T) is corrected in each time when a pulse number inputted from the photo sensor (49b) reaches a control pulse number. Line printing on the surface tape (31) is performed by means of the thermal head (13) with this print cycle algebra (T) as a print cycle (T).