Thermal Head Energizing Time Control at Astable Voltage
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Solution Overview
Problem
Conventional methods for thermal head energizing time control at astable voltage do not account for errors in resistance value and ambient temperature, which can affect print quality and stability.
Innovation Solution
A method that sets initial values for a decreasing variable number based on the type of printing medium and measured resistance value, continuously monitors and adjusts the chopping duty ratio of the thermal head's energization, and repeats this process until a predetermined value is reached or exceeded, ensuring precise control of energization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal head energizing time control is used, then power supply voltage variations are compensated, but resistance value errors and ambient temperature effects are not reflected in the control
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actual voltage at the thermal head and using this information to adjust the chopping duty ratio. The control unit compares the detected voltage with reference values and modifies the energization time accordingly, creating a closed-loop system that compensates for voltage variations, resistance errors, and temperature effects to maintain stable print quality
Solution Approach 2:
The patent dynamically changes the chopping duty ratio parameter based on detected voltage conditions and resistance value measurements. By adjusting this key parameter in response to environmental and electrical variations, the system maintains optimal thermal head performance despite changes in operating conditions
2Productivity
If the chopping duty ratio is adjusted based on voltage detection, then energization time is optimized, but complex control calculations are required
Solution Approach 1:
The patent performs preliminary measurements of the thermal head's resistance value before the printing operation begins. This advance characterization of the thermal head's electrical properties allows the control unit to pre-calculate appropriate chopping duty ratios and simplifies real-time control calculations by having reference data already available
Solution Approach 2:
The control unit automatically performs voltage detection, resistance value measurement, and chopping duty ratio calculation without requiring external intervention. The system self-adjusts the energization parameters based on its own measurements and internal calculations, reducing the need for complex external control 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
This approach ensures stable and consistent print quality by accurately reflecting resistance value and ambient temperature errors, preventing unintended ink ribbon cut-off and fusion, and maintaining optimal energization even at varying voltage levels.
Implementation Method 1
a thermal head (41) made up of plural heat elements (41A) which transmit heat to a surface tape (31)
Data Source
AI summary
First fixed value is set as decreasing variable number C and second fixed value corresponding to measured resistance value of a thermal head is determined as constant K(R). Energization of the thermal head is started immediately after start of printing period and the energization is kept until lapse of pulse application time calculated based on chopping duty ratio determined based on thermal head voltage and the constant K(R). Engergization of the thermal head is stopped at lapse of the pulse application time and withheld until lapse of unit time. Calculation value (C(V)×K(TH)) calculated based on temperature and voltage of the thermal head is decremented from the current decreasing variable number C to obtain renewed decreasing variable number C. When the renewed decreasing variable number C is larger than 0, serial processes of calculating pulse application time, keeping and withholding energization of the thermal head are repeated.