The inkjet printer is a kind of equipment that is controlled by software and uses non-contact method to mark products. The world's first commercial inkjet printer came from the late 1970s. After more than 40 years of technological upgrading, inkjet printers have undergone great changes in both type and structure, and have become a necessary artifact for packaging identification and traceability. Let's see different inkjet printers:
Classification in principle:
1. Continuous ink-jet technology
Under the action of the pressure of the ink supply pump, the ink passes through the ink pipeline from the ink tank, adjusts the pressure, viscosity and enters the spray gun. As the pressure continues, the ink is ejected from the nozzle. When the ink passes through the nozzle, the ink is broken into a series of continuous ink drops with equal spacing and the same size by the action of the piezoelectric crystal. The ejected ink continues to move downward and is charged through the charging electrode, and the ink drops are separated from the ink line in the charging electrode. A certain voltage is applied to the charging electrode, and when the ink drops are separated from the conductive ink line, they will instantly carry a negative charge proportional to the voltage applied to the charging electrode. By changing the voltage frequency of the charging electrode so that it is the same as the frequency of ink drop breakage, each ink drop can be charged with a predetermined negative charge. Under the continuous pressure, the ink flow continues to move downward and passes through the middle of two deflection plates with positive and negative voltages respectively. The charged ink drops will deflect when passing through the deflection plates, and the degree of deflection depends on the amount of charge carried. The uncharged ink drops will not deflect and will fly downward, flow into the recovery pipe, and finally return to the ink tank through the recovery pipe for recycling. Charged and deflected ink droplets fall at a certain speed and angle onto objects passing in front of the vertical nozzle.
2. Drop On Demand ink-jet technology
On-demand ink-jet technology inkjet printers are divided into three types, piezoelectric ink-jet technology, pressure valve ink-jet technology and thermal foaming ink-jet technology. Each type has different working principles.
1) Piezoelectric ink-jet technology: Piezoelectric inkjet printer is also called high-resolution inkjet printer or high-resolution inkjet printer. On the integrated nozzle, 128 or more piezoelectric crystals are used to control a plurality of orifices on the nozzle plate respectively. After processing by Central Processor, a series of electrical signals are output to each piezoelectric crystal through the drive plate, and the piezoelectric crystals deform, so that ink is ejected from the nozzle and falls on the surface of moving articles to form a dot matrix, thus forming characters, numbers or graphics. Then, the piezoelectric crystal returns to its original state. Due to the surface tension of the ink, new ink enters the nozzle. Because the density of ink dots per square centimeter is very high, piezoelectric technology can be used to print high-quality characters, complicated logos, bar codes and other information.
2) Solenoid valve type inkjet printer (dod industrial ink-jet printer): The nozzle consists of 7 or 16 groups of high precision intelligent micro valves. During inkjet printing, the characters or graphics to be printed are processed by the computer main board, and a series of electrical signals are output to the intelligent micro solenoid valve through the output board. The valves are opened and closed quickly, ink is ejected into ink dots depending on the internal Homeostasis pressure, and the ink dots form characters or graphics on the surface of the moving object to be printed.
3. Thermal Inkjet ink-jet technology Technology
TIJ, for short, uses a thin film resistor to heat less than 0.5% of the ink in the ink ejection area to form a bubble. This bubble expands at an extremely fast rate (less than 10 microseconds), forcing ink droplets to be ejected from the nozzle. The bubble continues to grow for a few microseconds before disappearing back onto the resistor. When the bubble disappears, the ink in the nozzle retracts. Then the surface tension will generate suction.
Classification from application:
1. Small Character Printer
The inkjet printer uses the charged deflection of ink to deflect the ink dots out of the normal flight path and toward the surface of the workpiece, and uses the amount of electricity charged to control the position of each ink droplet. In general, only when the ink drops change in the vertical direction, must the object to be printed and the nozzle move relatively, can we form the data we want to print. Ink jet printer logo has the following advantages: non-contact, fast speed, easy to edit and modify the content of ink jet printing data, and wide range of surface materials used by ink jet printer.
2. dod industrial ink-jet printer
If it is a 7-point nozzle, there are 7 independent valves to control its printing font to be larger, which is generally applied to outer boxes, outer packages or large workpieces, such as rough water pipes or asbestos boards, heat insulation boards and other workpieces. Professional inkjet printers such as small character series, high definition series, large character series and laser series are widely used in food, building materials, electronics, printing and other industries.
3. High-resolution inkjet printer
In principle, the high-resolution inkjet printer belongs to DOD (ink supply on demand) type inkjet printing. The high-resolution inkjet printer has a wider range of character heights of 1.2 mm-17 mm, and can print digital dot matrix fonts (imitation dot matrix). Chinese characters cannot use dot matrix, high-resolution fonts can be printed, and even any font on the computer can be printed. The printing speed is not affected by the font dot matrix and can reach 60m/min at the fastest. When the machine is running, the ink is ejected on demand, the ink is not recycled, and the ink concentration is consistent. No diluent (solvent) needs to be added, and the operation cost is lower than that of CIJ formula. The control system is simple and reliable, easy to operate and easy to maintain.
4. Laser code spraying machine
The laser printer uses software to deflect the laser beam and uses the high temperature of the laser to directly burn the surface of the product to be marked to form fonts or patterns.
The advantages of laser printer are as follows: ① reduce production cost, reduce consumables and improve production efficiency; ② the anti-counterfeiting effect is obvious; ③ is conducive to product tracking records; ④ increasing added value; ⑤ stable and reliable equipment performance; ⑥ Environmental protection and safety; ⑦ Dot Per Inch is extremely high and accurately controlled.
5, thermal transfer printing machine
The working principle of thermal transfer printing: each print head has a row of heating elements; These elements use glaze (a thin layer of glass) as a protective layer and are driven and heated at an appropriate time. The heat generated by these elements melts the ink on the ribbon and transfers the ink to the substrate due to the pressure of air pressure. Only the words of the thermal transfer printer are not typed independently and can be printed.
The fastest coding machine in the world can be 600MM per second.