The thermal print head consists of a row of heating elements, all of which have the same resistance. These elements are densely arranged, ranging from 200dpi to 600dpi. These elements will quickly generate high temperatures when a certain current is passed. When these components are reached, the temperature rises within a very short period of time, and the dielectric coating chemically reacts and develops color.
How to use and maintain the thermal print head
It is not only the output device of various computer systems, but also a serialized peripheral device gradually developed with the development of the host system. As the core component of the printer, the print head directly affects the quality of printing.
Use and maintenance of thermal print head
1. Ordinary users must not disassemble and assemble the print head by themselves, causing unnecessary losses.
2 Do not deal with the bumps on the print head by yourself, you must ask a professional to deal with it, otherwise the print head will be easily damaged;
3 Clean the dust inside the printer frequently;
4. Try not to use the thermal printing method, because the quality of thermal paper varies, and some surface is rough, and the thermal paper directly touches the print head, which is easy to damage the print head;
5 Clean the print head frequently according to the print volume. When cleaning, please remember to turn off the power of the printer first, and use a medical cotton swab dipped in anhydrous alcohol to clean the print head in one direction;
6. The print head should not work for a long time. Although the maximum parameter provided by the manufacturer indicates how long it can print continuously, as a user, when it is not necessary to print continuously for a long time, the printer should be given a rest;
8. Under the premise, the temperature and speed of the print head can be appropriately reduced to help prolong the life of the print head;
9. Choose the appropriate carbon ribbon according to your needs. The carbon ribbon is wider than the label, so that the print head is not easy to be worn out, and the side of the carbon ribbon that touches the print head is coated with silicone oil, which can also protect the print head. Use low-quality ribbons for the sake of cheapness, because the side of the low-quality ribbon that touches the print head may be coated with other substances or have other substances left, which may corrode the print head or cause other damage to the print head; 9 In a humid area or room When using the printer, special attention should be paid to the maintenance of the print head. Before starting the printer that has not been used for a long time, you should check whether the surface of the print head, rubber roller and consumables are abnormal. If it is damp or there are other attachments, please do not start it. The print head and rubber roller can be used with medical cotton swabs. It is best to replace the consumables with anhydrous alcohol for cleaning;
Thermal print head structure
The thermal printer selectively heats the thermal paper at certain locations, thereby producing corresponding graphics. Heating is provided by a small electronic heater on the printhead that is in contact with the heat-sensitive material. The heaters are logically controlled by the printer in the form of square dots or strips. When driven, a graphic corresponding to the heating element is generated on the thermal paper. The same logic that controls the heating element also controls the paper feed, allowing graphics to be printed on the entire label or sheet.
The most common thermal printer uses a fixed print head with a heated dot matrix. The print head shown in the figure has 320 square dots, each of which is 0.25mm×0.25mm. Using this dot matrix, the printer can print on any position of the thermal paper. This technology has been used on paper printers and label printers.
Usually, the paper feeding speed of the thermal printer is used as the evaluation index, that is, the speed is 13mm/s. However, some printers can print twice as fast when the label format is optimized. This thermal printer process is relatively simple, so it can be made into a portable battery-operated thermal label printer. Due to the flexible format, high image quality, fast speed and low cost printed by thermal printers, the barcode labels printed by it are not easy to be stored in an environment higher than 60°C, or exposed to ultraviolet light (such as direct sunlight) for long periods of time. time storage. Therefore, thermal barcode labels are usually limited to indoor use.
Thermal print head control
An image in the computer is decomposed into line image data for output, and sent to the print head respectively. For each point in the linear image, the print head will assign a heating point corresponding to it.
Although the print head can only print dots, to print complex things like curves, barcodes or pictures must be broken down into linear rows by computer software or a printer. Imagine cutting the image into lines as shown in the image above. The lines must be very thin, so that everything in the line becomes dots. Simply put, you can think of the heating spot as a “square” spot, the minimum width can be the same as the spacing between the heating spots. For example, the most common print head division rate is 8 dots/mm, and the pitch should be 0.125mm, that is, there are 8 heated dots per millimeter of heated line, which is equivalent to 203 dots or 203 lines per inch.
Post time: Mar-25-2022