A thermal printhead

Abstract

This utility model relates to the field of printhead technology, and more particularly to a thermal printhead that solves the problem in existing technologies where the printhead is prone to overheating due to heat accumulation when continuously printing high-density images or under conditions of large ambient temperature fluctuations. This overheating can lead to excessively dark print colors, paper carbonization, or even printhead burnout. A thermal printhead includes a frame, with the printhead fixedly connected to the inner side of the frame by screws. A top plate is slidably connected to the top of the frame, and a semiconductor cooling plate is fixedly connected to the bottom of the top plate. A side plate is fixedly connected to one side of the frame, and a cylinder is fixedly connected to one side of the side plate by bolts, with the cylinder's output shaft passing through the side plate. This utility model effectively solves the problems in existing technologies where unstable print quality, overheating, or insufficient heating are caused by untimely or uneven temperature control.

Description

Technical Field

[0001] This utility model relates to the field of printhead technology, and in particular to a thermal printhead. Background Technology

[0002] The thermal printhead is the core component of thermal printing equipment. It primarily uses heating elements to selectively heat the surface of thermal paper, causing a chemical reaction and color development to form the desired text, images, or barcode information. It is widely used in POS machines, receipt printers, medical equipment, logistics label printing, and many other fields. Its working principle utilizes a fine array of heating resistors, driven by a control signal, to heat the paper precisely, achieving fast, inkless, non-contact printing. Due to its advantages such as simple structure, low operating cost, and high printing speed, the thermal printhead plays a crucial role in modern information output devices. As a key component determining print quality, speed, and stability, its temperature control accuracy, heat dissipation performance, and response speed have a decisive impact on the clarity and uniformity of the printed image and the continuous working capability of the equipment.

[0003] Specifically, when printing high-density images continuously or under conditions of significant temperature fluctuations, the printhead is prone to overheating due to heat accumulation, leading to excessively dark prints, paper carbonization, or even printhead burnout. Conversely, printing in low-temperature environments or at short intervals may result in insufficient heating, leading to pale prints and blurred text, affecting information recognition. Therefore, given the numerous shortcomings of existing technologies, we urgently need an innovative thermal printhead to solve these problems. Utility Model Content

[0004] The purpose of this invention is to provide a thermal printhead that solves the problem in the prior art where the printhead is prone to overheating due to heat accumulation when continuously printing high-density images or when the ambient temperature fluctuates greatly, which can lead to excessively dark printing colors, paper carbonization, or even printhead burnout.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A thermal printhead includes a frame, with the printhead fixedly connected to the inner side of the frame by screws. A top plate is slidably connected to the top of the frame, and a semiconductor cooling plate is fixedly connected to the bottom of the top plate. A side plate is fixedly connected to one side of the frame, and a cylinder is fixedly connected to one side of the side plate by bolts. The output shaft of the cylinder passes through the side plate, and the output shaft of the cylinder is fixedly connected to one side of the top plate. A heating plate is provided at the bottom of the printhead, and both sides of the heating plate are fixedly connected to the inner wall of the frame. Thermometers are installed on both sides of the frame.

[0006] Preferably, a side frame is fixedly connected to one side of the frame, and an air outlet hood is fixedly connected to the inner side of the side frame. A fan is fixedly connected to one side of the outer wall of the side frame by bolts, and one side of the air outlet hood is connected to the outlet of the fan.

[0007] Preferably, the outlet of the fan is connected to a duct, and one end of the duct is connected to the top side of the air outlet hood.

[0008] Preferably, a number of heating rods are provided on one side of the frame, and one end of all the heating rods penetrates through the side wall of the frame, wherein one end of all the heating rods is fixedly connected to one side of the heating plate.

[0009] Preferably, sliders are fixedly connected to both sides of the bottom of the top plate, and both sliders are slidably connected to the top of the frame through a groove.

[0010] Preferably, the two sliders are fitted with the two grooves with clearance.

[0011] This utility model has the following beneficial effects: By placing the printhead within the frame and configuring a cylinder-driven movable top plate on top of it, along with a semiconductor cooling plate fixed to the bottom of the top plate, combined with thermometers installed on both sides of the frame and a heating plate at the bottom, this technology effectively solves the problems of unstable print quality, overheating, or insufficient heating caused by untimely and uneven temperature control in existing technologies. The heating plate can actively raise the initial temperature of the printhead in low-temperature environments, preventing pale colors and blurry images due to excessively low temperatures, ensuring printing reliability in cold seasons or low-temperature environments. The semiconductor cooling plate, as an active heat dissipation element, can quickly absorb the accumulated heat on the printhead surface, preventing overheating caused by continuous printing, avoiding thermal paper carbonization, printhead burnout, and other malfunctions, significantly improving the continuous working capacity and service life of the equipment. The cylinder-driven top plate moves the semiconductor cooling plate along the printhead direction, covering the entire printing area with cooling, breaking away from the limitations of traditional fixed cooling methods that only provide cooling for a limited amount of time. The limitations of localized cooling are overcome by achieving uniform temperature control, reducing printing streaks or color differences caused by uneven thermal stress distribution. A thermometer collects temperature data in real time, providing feedback for heating and cooling operations, supporting closed-loop control logic, and improving the response speed and accuracy of the temperature control system. The entire structure integrates heating and cooling functions into a single device, adapting to different environmental conditions and printing loads, enhancing the environmental adaptability and operational stability of the thermal printhead. The frame, as a load-bearing structure, securely fixes the printhead with screws, ensuring a stable and reliable heat transfer path between the heating element and the cooling / heating components. This design effectively balances the thermal state of the printhead under different operating conditions through active temperature control, significantly improving the clarity, uniformity, and consistency of printed images, reducing scrap rates and equipment failure rates caused by abnormal temperatures, meeting the high-precision and high-reliability output requirements of modern printing equipment, and possessing good practical value and promising prospects for widespread application. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the main structure of this utility model; Figure 2 This is a side view of the structure of this utility model; Figure 3 This is a top view of the structure of this utility model; Figure 4 This is a schematic diagram of the side frame structure of this utility model; Figure 5This is a schematic diagram of the inner structure of this utility model.

[0014] In the diagram: 1. Frame; 2. Print head; 3. Thermometer; 4. Top plate; 5. Slider; 6. Slide rail; 7. Semiconductor cooling plate; 8. Side plate; 9. Cylinder; 10. Air outlet hood; 11. Side frame; 12. Heating rod; 13. Fan; 14. Air duct; 15. Heating plate. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0016] Reference Figure 1-5 A thermal printhead includes a frame 1, a printhead 2 fixedly connected to the inner side of the frame 1 by screws, a top plate 4 slidably connected to the top of the frame 1, and a semiconductor cooling plate 7 fixedly connected to the bottom of the top plate 4. A side plate 8 is fixedly connected to one side of the frame 1, and a cylinder 9 is fixedly connected to one side of the side plate 8 by bolts. The output shaft of the cylinder 9 passes through the side plate 8, and the output shaft of the cylinder 9 is fixedly connected to one side of the top plate 4. A heating plate 15 is provided at the bottom of the printhead 2, and both sides of the heating plate 15 are fixedly connected to the inner wall of the frame 1. A thermometer 3 is installed on both sides of the frame 1.

[0017] When a thermal printhead is needed for printing, the frame 1 is first fixed to the printer's moving mechanism using the mounting structure, ensuring that the printhead 2 maintains an appropriate gap and alignment accuracy with the thermal paper surface. During normal printing, the heating element inside the printhead 2 selectively heats the thermal paper according to the input image signal, completing the color output of text or graphics. When the ambient temperature is low or the equipment is restarted after a long period of shutdown, the initial temperature of the printhead 2 may be low, resulting in pale colors and unclear images. At this time, the heating plate 15 is activated, which transfers heat to the substrate area of ​​the printhead 2 through heat conduction, quickly raising its overall operating temperature and allowing it to reach the optimal printing temperature range in a short time, ensuring print quality in low-temperature environments. However, when continuously printing high-density images or working at high frequency for a long time, the printhead 2's temperature rises rapidly due to continuous heating. If it is not cooled down in time, overheating can easily occur, affecting printing uniformity and even causing thermal paper carbonization or printhead damage. At this time, the semiconductor cooling plate 7 installed at the bottom of the top plate 4 is activated. After being powered on, the semiconductor cooling plate 7 utilizes the Peltier effect on its cold surface. The system generates low temperatures, absorbing heat from the surface of printhead 2 and transferring it to the hot end, achieving active cooling. Simultaneously, to improve the uniformity and efficiency of cooling, a cylinder 9, bolted to the side plate 8, is activated. The output shaft of cylinder 9 pushes the top plate 4, which is fixedly connected to it, to reciprocate along the sliding structure at the top of the frame 1. This causes the semiconductor cooling plate 7 to slide axially back and forth above or to the side of printhead 2, ensuring that the cooling effect covers the entire heating area of ​​printhead 2, avoiding insufficient or uneven cooling in certain areas. This achieves dynamic and uniform temperature control of the entire printhead 2. Throughout the operation, thermometers 3 installed on both sides of the frame 1 monitor the ambient or surface temperature around printhead 2 in real time and feed the temperature signal back to the printer's control system. Operators or the automatic control module can adjust the working state of heating plate 15 or semiconductor cooling plate 7 based on the temperature data, forming a closed-loop temperature control mechanism. When the printing task is completed or the temperature returns to the set range, heating plate 15 and semiconductor cooling plate 7 are turned off. Cylinder 9 retracts, resetting the top plate 4 and semiconductor cooling plate 7, and the device enters standby mode, ready for the next printing task.

[0018] Furthermore, a side frame 11 is fixedly connected to one side of the frame 1, and an air outlet hood 10 is fixedly connected to the inner side of the side frame 11. A fan 13 is fixedly connected to one side of the outer wall of the side frame 11 by bolts, and one side of the air outlet hood 10 is connected to the outlet of the fan 13. When the semiconductor cooling plate 7 is working, the fan 13 starts, draws in external air and blows it directionally onto the hot end surface of the semiconductor cooling plate 7 through the air outlet hood 10, accelerates the convection and dissipation of heat at the hot end, improves the cooling efficiency of the semiconductor cooling plate 7, prevents its hot end temperature from being too high and causing a decrease in the cooling capacity of the cold end, thereby enhancing the overall heat dissipation performance and achieving the effect of improving the active cooling effect and ensuring temperature control stability.

[0019] Furthermore, the outlet of the fan 13 is connected to a duct 14, and one end of the duct 14 is connected to the top side of the exhaust hood 10. The duct 14 guides the airflow generated by the fan 13 into the interior of the exhaust hood 10, forming a closed air duct structure, reducing airflow leakage and energy loss, ensuring that the airflow is concentrated and stably blown towards the hot end area of ​​the semiconductor cooling plate 7, improving the efficiency of airflow utilization and heat dissipation uniformity, avoiding local overheating, and facilitating flexible layout and installation and maintenance between the fan 13 and the exhaust hood 10, thus achieving the effect of optimizing the airflow structure and enhancing heat dissipation reliability.

[0020] Furthermore, a number of heating rods 12 are provided on one side of the frame 1, and one end of all the heating rods 12 penetrates through the side wall of the frame 1. One end of all the heating rods 12 is fixedly connected to one side of the heating plate 15. The heating rods 12 convert external electrical energy into heat energy and transfer the heat directly to the heating plate 15 through heat conduction. The heat is then evenly conducted to the substrate area of ​​the printhead 2 by the heating plate 15. The arrangement of multiple heating rods 12 improves the heating power and heat distribution uniformity, avoids the temperature gradient caused by single-point heating, and the external heating rods 12 facilitate replacement and maintenance without affecting the main structure of the printhead, thus achieving the effect of enhancing heating efficiency and improving structural maintainability.

[0021] Furthermore, sliders 5 are fixedly connected to both sides of the bottom of the top plate 4, and both sliders 5 are slidably connected to the top of the frame 1 through the slide groove 6. When the cylinder 9 drives the top plate 4 to move along the direction of the print head 2, the sliders 5 slide synchronously in the slide groove 6. The slide groove 6 provides a precise guide path for the sliders 5, restricting their vertical and horizontal degrees of freedom, ensuring that the top plate 4 and the semiconductor cooling plate 7 remain stable and do not deviate during the movement, preventing interference or poor contact between the cooling plate and the print head due to shaking, ensuring the stability of the movement process and the continuity of the cooling effect, and achieving the effect of improving the motion guidance accuracy and running stability.

[0022] Furthermore, both sliders 5 and the two grooves 6 are clearance fits. In summary: When a thermal printhead is needed for printing, first, the frame 1 is fixed to the printer's moving mechanism using the mounting structure, ensuring that the printhead 2 maintains an appropriate gap and alignment accuracy with the thermal paper surface. During normal printing, the heating element inside the printhead 2 selectively heats the thermal paper according to the input image signal, completing the color output of text or graphics. When the ambient temperature is low or the equipment is restarted after a long period of shutdown, the initial temperature of the printhead 2 may be low, resulting in pale colors and unclear images. In this case, several heating rods 12 installed on one side of the frame 1 are activated. After being powered on, the heating rods 12 convert electrical energy into heat energy and transfer the heat to the heating plate 1 fixedly connected to them through one end that penetrates the side wall of the frame 1. 5. The heating plate 15 then evenly conducts heat to the substrate area of ​​the printhead 2, achieving rapid heating and allowing the printhead 2 to reach its optimal operating temperature range in a short time, ensuring print quality in low-temperature environments. However, during continuous printing of high-density images or long-term high-frequency operation, the printhead 2 experiences a rapid temperature rise due to continuous heating. If it is not cooled in time, overheating can easily occur, affecting print uniformity and even causing thermal paper carbonization or printhead damage. At this time, the semiconductor cooling plate 7 installed at the bottom of the top plate 4 is activated. After being powered on, the semiconductor cooling plate 7 utilizes the Peltier effect to generate a low temperature on its cold side, absorbing the heat from the surface of the printhead 2. At the same time, to prevent the cooling efficiency from decreasing due to heat accumulation at its hot end, the fan 1, which is fixed to the outer wall of the side frame 11 by bolts, is activated. 3. The airflow generated by the fan 13 is guided through the air duct 14 to the exhaust hood 10, and then blown directionally by the exhaust hood 10 onto the hot end surface of the semiconductor cooling plate 7, accelerating the convection and dissipation of heat and improving the overall heat dissipation efficiency. To further improve the uniformity and coverage of cooling, the cylinder 9 fixed to the side plate 8 by bolts is activated. The output shaft of the cylinder 9 pushes the top plate 4, which is fixedly connected to it, to move along the top of the frame 1. The sliders 5 on both sides of the bottom of the top plate 4 slide synchronously in the slide groove 6. The sliders 5 and the slide groove 6 are fitted with a clearance to ensure smooth sliding and avoid jamming due to thermal expansion or vibration. The top plate 4 drives the semiconductor cooling plate 7 to move back and forth axially above or to the side of the print head 2, so that the cooling effect covers the entire heat-generating area and avoids local cooling. This addresses the issue of insufficient or uneven cooling, thereby achieving dynamic and uniform temperature control of the entire printhead 2. Throughout the entire operation, thermometers 3 installed on both sides of the frame 1 monitor the ambient temperature or surface temperature around the printhead 2 in real time and feed the temperature signal back to the printer's control system. Operators or the automatic control module can adjust the working status of the heating rod 12, heating plate 15, semiconductor cooling plate 7, fan 13, and cylinder 9 in a timely manner based on the temperature data, forming a closed-loop temperature control mechanism. When the printing task is completed or the temperature returns to the set range, the heating rod 12, heating plate 15, semiconductor cooling plate 7, and fan 13 are turned off, and the cylinder 9 retracts, causing the top plate 4 and semiconductor cooling plate 7 to reset, and the equipment enters standby mode, ready for the next printing task.By fixing the printhead 2 inside the frame 1 and installing a movable top plate 4 driven by a cylinder 9 on its top, with a semiconductor cooling plate 7 connected to the bottom of the top plate 4, combined with the heating plate 15 at the bottom of the printhead 2 and the thermometers 3 on both sides of the frame 1, active and dynamic temperature control of the printhead 2 is achieved. This effectively solves the problems of unstable printing quality, overheating, or insufficient heating caused by untimely or uneven temperature control in the prior art. Multiple heating rods 12 are distributed on one side of the frame 1 and penetrate the side wall to connect with the heating plate 15, improving heating power and heat conduction efficiency, ensuring that the printhead 2 can quickly heat up to the working temperature in low-temperature environments, and avoiding pale printing colors. The semiconductor cooling plate 7, combined with the fan 13, air duct 14, and air outlet shroud 10, constitutes a forced air cooling auxiliary system. The airflow generated by the fan 13 is guided through the air duct 14 to the air outlet shroud 10 and then concentrated towards the hot end of the semiconductor cooling plate 7, significantly improving heat dissipation efficiency, preventing the cooling capacity from decreasing due to overheating of the hot end, and ensuring the continuous effectiveness of the cooling system. The cylinder 9 drives the top plate 4, which in turn moves the semiconductor cooling plate 7 back and forth, so that the cooling effect covers the entire length of the printhead 2. This breaks the limitations of fixed cooling methods, achieves uniform temperature distribution, and reduces printing color difference or carbonization caused by local overheating. The sliders 5 on both sides of the bottom of the top plate 4 are slidably connected to the slide grooves 6 on the top of the frame 1, and adopt a clearance fit design. This ensures the smooth movement of the top plate 4 while allowing for small deformation and thermal expansion space, preventing jamming and structural damage, and improving the reliability and service life of the motion mechanism. The thermometer 3 provides real-time temperature data feedback and supports the formation of closed-loop control logic, making heating and cooling operations more targeted and responsive. The entire device integrates heating, cooling, movement control, and temperature monitoring into one unit, adapting to the needs of different environmental conditions and printing loads. It significantly improves the temperature control accuracy, printing stability, and equipment durability of the thermal printhead, meeting the requirements of modern printing equipment for high-quality and high-reliability output, and has good practicality and promotional value.

[0023] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A thermal printhead, comprising a frame (1), characterized in that, The inner side of the frame (1) is fixedly connected to the print head (2) by screws. The top of the frame (1) is slidably connected to the top plate (4), and the bottom of the top plate (4) is fixedly connected to the semiconductor cooling plate (7). The side plate (8) is fixedly connected to one side of the frame (1), and the side plate (8) is fixedly connected to the cylinder (9) by bolts. The output shaft of the cylinder (9) passes through the side plate (8). The output shaft of the cylinder (9) is fixedly connected to one side of the top plate (4). The bottom of the print head (2) is provided with a heating plate (15), and both sides of the heating plate (15) are fixedly connected to the inner wall of the frame (1). The thermometers (3) are installed on both sides of the frame (1).

2. A thermal printhead according to claim 1, characterized in that, A side frame (11) is fixedly connected to one side of the frame (1), and an air outlet hood (10) is fixedly connected to the inner side of the side frame (11). A fan (13) is fixedly connected to one side of the outer wall of the side frame (11) by bolts, and one side of the air outlet hood (10) is connected to the outlet of the fan (13).

3. A thermal printhead according to claim 2, characterized in that, The outlet of the fan (13) is connected to a duct (14), and one end of the duct (14) is connected to the top side of the air outlet cover (10).

4. A thermal printhead according to claim 1, characterized in that, The frame (1) has several heating rods (12) on one side, and one end of all the heating rods (12) penetrates the side wall of the frame (1), wherein one end of all the heating rods (12) is fixedly connected to one side of the heating plate (15).

5. A thermal printhead according to claim 1, characterized in that, The top plate (4) is fixedly connected to two sliders (5) on both sides of the bottom, and the two sliders (5) are slidably connected to the top of the frame (1) through the slide groove (6).

6. A thermal printhead according to claim 5, characterized in that, The two sliders (5) are respectively fitted with the two grooves (6) with clearance.

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