Principle analysis of bar code printer

1. Principle of thermal printing

There are two main types of thermal printing for bar code printers. One is the way that the thermal paper changes color when it is heated, which is often referred to as the thermal method. The other is the transfer of ribbon ink, which is often referred to as thermal transfer. Under the thermal printing mode, the working principle of the bar code printer is that the printing head is hot, and the thermal label medium changes color after being heated at the heating point of the bar code printer's printing head to display the content to be printed. Labels using thermal printing media will gradually fade under the action of sunlight and have a short storage time (usually no more than 6 months). In many applications, labels need to be stored for a long time, which requires thermal transfer printing.

In the thermal transfer printing mode, the barcode printer can use the thermal transfer ribbon as the medium to print on the label printing medium. The computer controls the heat of the printing head of the bar code printer, and the carbon powder coating of the thermal transfer carbon belt is melted and transferred to the label printing medium under the thermal action of the printing head and the pressure of the printing head to display the graphics to be printed and written words. Labels printed by thermal transfer can be stored for a longer time according to the material of the label and the material of the carbon tape, such as those printed by resin based carbon tape

Pet durability labels can usually be stored for 3-5 years or even longer.

2. Technical principle of label transmission

The label drive of bar code printer refers to the label feeding mechanism. At present, there are two methods adopted. One is the flat pressing method of the print head, and the other is the hanging pressing method of the print head. Generally, the front roller shaft is only used to drive the paper feeding (some wide bar code machines also use the front and rear roller shafts to drive the paper feeding at the same time). The hanging pressing method adopts the front and rear silver shafts to drive the paper feeding. Therefore, the flat pressing method includes the printing head, label The front roller is in a pressed state, while the printing head, label and front roller can be in an incompletely pressed state in the suspended pressing mode.

The paper feeding mechanism of the label is driven by the same motor whether it is in the flat pressing mode or in the hanging pressing mode. If it is driven by double roller shafts, it is generally driven by belt drive double editing shafts. In the principle of bar code printer, this is the standard that can best judge the durability of the bar code printer. The gears of the driving belt of the bar code printer with good durability are made of metal parts to ensure the service life of the driving structure during the high-speed operation of the bar code printer. The drive of the accessories of the barcode printer, such as the retractor of the barcode printer and the stripper of the barcode printer, is also the drive motor of the paper feeding mechanism.

3. Technical principle of carbon belt drive

At present, there are two ways to drive the carbon belt of barcode printer. One is to use the same drive motor as the label feeding mechanism, and the other is to use a separate motor to drive (commonly used in the hanging type printing mode). When a set of drive motors is used for the carbon belt drive and label feeding mechanism of the bar code printer, the energy is transmitted through the belt. There are generally two carbon belt shafts. In the front the carbon belt shaft at the front is the driving shaft, and the carbon belt shaft at the rear is the driven shaft. The driving shaft is driven by the motor and acts synchronously with the printing of the label paper. The driven shaft makes the carbon belt straight and flat by the damping plate or the damping spring. When the carbon belt drive of the barcode printer is driven by a single motor, the front and rear double motors are generally used to control the action of the carbon belt. The greatest advantage of this method is that the carbon belt saving function of barcode printing can be realized.

4. Automatic detection principle of sensor

The automatic detection of bar code printer sensor mainly includes three parts. One is the label positioning sensor, which can detect interval label, black label label and hole position label. The other is the ribbon detection sensor, which can detect whether the ribbon is installed and whether the ribbon is exhausted in the thermal transfer mode. Another is the print head opening / closing detection sensor, which can detect whether the print head is closed correctly.

5. DSP data processing principle

The DSP data processing of the barcode printer is a way of data conversion, that is, the computer sends graphic instructions to the barcode machine, and the barcode machine drives the thermal element of the print head to generate heat and print relevant contents through data storage and data processing.