Thermal Head Pulse Timing for High-Speed Printing Heat Management
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Solution Overview
Problem
High-speed printing technologies face challenges in maintaining heat generation efficiency in thermal heads due to heat loss and temperature delays, leading to issues like print blurring and heat accumulation, especially as printing speeds increase, requiring adjustments in pulse application times and potentially increasing costs.
Innovation Solution
A printing apparatus employing heat history control with new energization correction, utilizing a thermal head with a control program that adjusts the timing and width of main and sub pulses to ensure consistent heat distribution, allowing for shorter application periods without compromising printing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the application period is shortened to increase printing speed, then productivity is improved, but heating time becomes insufficient leading to heat generation shortage
Solution Approach 1:
The invention applies a sub pulse before the main pulse to preliminarily heat the heater elements. This preliminary heating action ensures that when the main pulse is applied during the shortened application period, the heater elements are already at an elevated temperature, allowing sufficient heat generation for printing despite the reduced time available.
2Power
If voltage or current is increased to compensate for shorter heating time, then heat generation is improved, but device complexity and cost increase
Solution Approach 1:
Instead of increasing voltage or current to compensate for shorter heating time, the invention uses preliminary heating with a sub pulse. This approach maintains the same power specifications while achieving sufficient heat generation by extending the effective heating process into the preceding application period.
3Power
If sub pulse is applied in the same application period as main pulse, then heat generation is improved, but application period becomes too long for high-speed printing
Solution Approach 1:
The sub pulse is positioned in the preceding application period rather than the same application period as the main pulse. This timing arrangement allows the heater elements to be preliminarily heated without extending the critical application period, enabling high-speed printing while maintaining sufficient heat generation.
4Temperature
If heating time is extended to prevent heat loss, then temperature stability is improved, but non-heating time is reduced causing heat accumulation
Solution Approach 1:
The invention selectively applies heating to only those heater elements that require it, based on the printing pattern. By using preliminary heating with sub pulses targeted at specific heater elements, the system maintains temperature stability where needed while preserving non-heating time for heat dissipation in other areas, preventing heat accumulation.
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
Enables high-speed printing with improved heat management, preventing heat accumulation and maintaining print quality by optimizing the application of main and sub pulses, thus enhancing the thermal head's performance without the need for hardware upgrades.
Implementation Method 1
When the heater elements are heated by application of a main pulse, a portion of the heat is lost at the periphery of the heater elements
Data Source
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AI summary
A printing apparatus (1) wherein each application period (F) is set as a fixed period of time ranging from a main heating start point (ms0) which shows when application of a main pulse (MP) for main heating to cause a printing medium (31) to develop color starts at a line head (41B) of a thermal head (41), to a next main heating start point (ms1), to cause successive printed dots to be formed on the printing medium (31) in a sub-scanning direction (D2) of the thermal head (41); and a control unit (60) carries out application of a sub pulse (SP) for auxiliary heating which, when applied independently, cannot cause the printing medium (31) to develop color, but, when applied so as to compensate main heating by the main pulse (MP) as applied in a next application period (F) can cause the printing medium (31) to develop color, with respect to each of heater elements (41A) constituting the line head (41B) of the thermal head (41) in accordance with a following constraint (A): (A) the sub pulse (SP) is applied within a current application period (F) wherein the printing medium (31) is not caused to develop color, irrespective of whether the next application period (F) wherein the main pulse (MP) for main heating is applied to cause the printing medium (31) to develop color starts immediately after the current application period (F) wherein the printing medium (31) is not caused to develop color.