Thermal Head Temperature Sensor Placement for Printing Quality
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Solution Overview
Problem
In thermal printing apparatuses, accurately correcting the amount of energy applied to the heating elements is challenging due to deviations in temperature detection between the thermal head and the printing medium, often resulting in faint, patchy, or blurred prints.
Innovation Solution
A printing apparatus is designed with a thermal head, two conveyance paths for an ink ribbon and a printing object, and two temperature sensors positioned to minimize heat interference, allowing for precise correction of energy application based on detected temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ambient temperature sensor is provided on the side of the thermal head with respect to the printing medium, then the temperature detection is simplified, but the accuracy of correcting the amount of applying energy is degraded due to heat interference from the thermal head
Solution Approach 1:
The patent introduces a heat shield (intermediate structure) between the thermal head and the ambient temperature sensor to block heat interference. This heat shield acts as an intermediary that prevents direct thermal coupling while allowing the sensor to still detect ambient temperature changes accurately, thus resolving the contradiction between simplified structure and measurement accuracy.
Solution Approach 2:
The patent divides the internal space into multiple thermal zones by positioning temperature sensors at different locations - one near the thermal head and another away from it. This segmentation allows independent measurement of different thermal environments, enabling accurate correction of applying energy while maintaining structural simplicity.
2Loss of energy
If the amount of applying energy is excessively small, then energy consumption is reduced, but printing quality deteriorates with faint and patchy characters
Solution Approach 1:
The patent implements a feedback mechanism where temperature sensors continuously monitor the thermal state of the thermal head and printing medium, and the controlling unit adjusts the amount of applying energy in real-time based on these temperature readings. This feedback loop ensures optimal printing quality while minimizing energy consumption by applying only the necessary energy rather than excessive energy.
Solution Approach 2:
The patent dynamically changes the applying energy parameter based on detected temperature conditions. By adjusting the energy parameter according to real-time temperature feedback, the system achieves high printing quality while avoiding unnecessary energy consumption that would occur with fixed high-energy settings.
3Productivity
If the amount of applying energy is excessively large, then printing speed can be maintained, but printing quality deteriorates with blurred characters
Solution Approach 1:
The feedback control system monitors temperature conditions and adjusts applying energy to maintain optimal printing quality without excessive energy application. This prevents character blurring while sustaining printing speed by ensuring energy is applied efficiently rather than in excessive amounts that would degrade quality.
Solution Approach 2:
The patent makes the applying energy dynamic rather than static, adjusting it in real-time based on thermal conditions. This dynamic adjustment allows the system to maintain high printing speed when conditions permit while preventing quality degradation through reduced energy application when thermal conditions indicate risk of blurring.
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 configuration enables high-accuracy correction of energy application, reducing printing defects by accurately accounting for the temperature changes in both the thermal head and the ink ribbon, thereby improving print quality.
Implementation Method 1
an energy is applied to a heating element of a thermal head, and printing is carried out by imparting heat to a printing medium by the heating element that has generated heat
Implementation Method 2
when temperature of the thermal head and temperature of the printing medium which is heated by the heating element at the time of printing are identified
Data Source
AI summary
A printing apparatus includes: a main body having a space therein, a thermal head arranged on a substrate provided in the space, the thermal head having heating elements arranged along a predetermined arrangement direction; a first conveyor which conveys an ink ribbon along a first conveyance path orthogonal to the arrangement direction, a second conveyor which conveys a printing object along a second conveyance path orthogonal to the arrangement direction and on an opposite side of the thermal head with respect to the first conveyance path, a first temperature sensor provided in a first space on a side of the thermal head with respect to the first conveyance path, a second temperature sensor provided in a second space between the first conveyance path and the second conveyance path, and a processor.