Thermal Printhead Temperature Control via Dual Sensor Compensation
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Solution Overview
Problem
Existing thermal printers fail to maintain high print quality when there is a significant temperature difference between the thermal printhead and the print medium, leading to printing errors due to inadequate heating control.
Innovation Solution
A thermal printer system that includes both a printhead sensor to measure the thermal printhead temperature and an environment sensor to measure the environment temperature, with a processor that computes a compensated temperature value to adjust the heating of the thermal printhead, ensuring optimal energy application based on the temperature gap between the two.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the energy applied to the thermal printhead is reduced as the printhead becomes hot during printing, then the printhead temperature is controlled, but print quality suffers when the print medium is cold
Solution Approach 1:
The system uses feedback from two temperature sensors (printhead sensor and environment sensor) to continuously monitor both printhead temperature and environment temperature. The processor compares these temperatures and adjusts the energy applied to heating elements based on the temperature difference, ensuring both temperature control and print quality are maintained
Solution Approach 2:
The system changes the parameter being controlled from just printhead temperature to a compensated temperature value that accounts for both printhead temperature and environment temperature. This parameter change allows the system to adapt energy application based on the temperature gap between printhead and print medium
2Device complexity
If only printhead temperature is used for control, then the control system is simple, but the system cannot compensate for environment temperature differences
Solution Approach 1:
The control system is segmented into multiple independent components: a printhead sensor for monitoring printhead temperature, an environment sensor for monitoring environment temperature, and a processor that separately processes both temperature inputs. This segmentation allows the system to gather comprehensive temperature data while maintaining modular, manageable complexity
Solution Approach 2:
The processor acts as an intermediary that receives inputs from both sensors, compares the temperatures, and computes a compensated temperature value. This intermediary processing step enables the system to adapt to environment temperature differences without requiring complex hardware changes
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 maintains print quality by compensating for temperature differences between the printhead and the print medium, preventing overheating or underheating, and reducing printing errors.
Implementation Method 1
an array of heating elements positioned close to a print-medium path... control the energy applied to the thermal printhead for heating during printing
Implementation Method 2
A typical thermal printhead uses a temperature sensor (e.g., thermistor) integrated with the thermal printhead to measure a printhead temperature
Data Source
AI summary
Control of the print temperature for a thermal printer is disclosed. Two temperature sensors are used to sense the temperature of both the thermal printhead and the environment around the print medium. In this way, the energy applied to the thermal printhead's heating elements may be adjusted to match an ideal print temperature, which depends on both the printhead temperature and the print-medium temperature.