Thermal Printer Control Adjusting Pulse Energy for Heat Management
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Solution Overview
Problem
Conventional thermal printers face issues with heat accumulation in the thermal head, leading to printing faults such as bold characters and unclear print-outs, especially at high printing speeds or temperatures, due to the difficulty in accurately measuring the temperature of the heater elements and the resulting energy imbalances during pulse application periods.
Innovation Solution
A printing control apparatus that adjusts the energization pattern based on temperature and printing speed by varying the proportion of sub-pulse and main-pulse energy amounts within each pulse application period, using a temperature measuring unit and a printing-speed calculating unit to optimize the energization times, ensuring sufficient energy for printing while minimizing heat accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a main pulse and sub pulse are applied to heater elements for printing, then printing energy is sufficient and weak print-outs are prevented, but heat accumulation occurs causing bold characters and unclear print-outs
Solution Approach 1:
The patent applies dynamics by making the pulse application pattern adaptive rather than fixed. The control unit dynamically adjusts between different pulse patterns (first pattern with sub-pulse for low temperature, second pattern without sub-pulse for high temperature) based on real-time temperature detection from the thermistor, allowing the system to respond to changing thermal conditions and prevent heat accumulation while maintaining print quality
Solution Approach 2:
The patent changes the parameter of pulse application pattern based on temperature conditions. When temperature exceeds a predetermined threshold, the system transitions from applying a first pattern (with sub-pulse) to a second pattern (without sub-pulse), effectively changing the energy input parameters to control heat accumulation while maintaining sufficient printing energy when needed
2Productivity
If printing speed is increased, then productivity improves, but heat accumulation occurs because temperature does not have time to decrease
Solution Approach 1:
The patent implements feedback control by continuously monitoring temperature with the thermistor and using this information to adjust the pulse application pattern. The control unit receives temperature feedback and automatically switches between printing patterns, ensuring that even at high printing speeds, heat accumulation is prevented by reducing or eliminating sub-pulses when temperature exceeds thresholds
3Ease of operation
If temperature detection is performed away from heater elements, then measurement is feasible, but measured temperature is lower than actual heater element temperature
Solution Approach 1:
The patent applies preliminary anti-action by proactively switching to a second pulse pattern (without sub-pulse) when the measured temperature approaches or exceeds a predetermined threshold, before the actual heater element temperature becomes excessively high. This anticipatory measure compensates for the temperature measurement lag and spatial offset, preventing heat accumulation before it causes printing faults
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 effectively prevents weak print-outs and unclear print-outs by dynamically adjusting the energy distribution during pulse application periods, ensuring the necessary energy is applied while reducing heat accumulation, thus maintaining print quality at varying speeds and temperatures.
Implementation Method 1
temperature detected by a thermistor disposed at a location set off from heater elements on the thermal head
Implementation Method 2
Heating of selected heater elements is carried out by applying a driving pulse to each selected heater element for predetermined period of time
Data Source
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AI summary
Provided is a printing control apparatus capable of avoiding weak print-out of a dot in one pulse application period as well as avoiding unclear print-out in other pulse application periods to follow the one pulse application period. In the printing control apparatus, there are arranged one pulse application period F1 of which from-start-to-end is series of sub-pulse application time S, main-pulse application time M1 and non-heating time C1 and other pulse application periods F2, F3... which follow one pulse application period F1 and of which from-start-to-end is repeated series of main-pulse application times M2, M3... and non-heating times C2, C3.... As temperature is higher, proportion of applied-for-sub-pulse energy amount to total energy amount in one pulse application period is made larger. As temperature is higher, proportion of applied-for-main-pulse energy amount to total energy amount in other pulse application periods F2, F3... that follow one pulse application period is made smaller.