Computer keyboard printing process

With the constant popularity of computers, the keyboard has become the most frequently used and most commonly used input device. The keyboard structure has experienced the development of mechanical, plastic film, capacitive, and conductive rubber types, and the character printing method on the keyboard has also made great progress.

1 Traditional Keyboard Printing Technology

1) Laser printing

Laser printing sounds unpredictable, but it is actually very simple. Laser printing is the use of laser engraving technology to burn black grooves on the keycap. Because the traces they make are linear, the arrows on common laser-printed keyboards are hollow.

For a long time, people have been erroneously thinking that using laser-printed keyboards is a sign of big factories and high-end products. In fact, laser printing is a sign of a big factory, because laser printers are expensive, and the price of a Siemens full-automatic keyboard printer is nearly one million US dollars. This is not an ordinary small factory can afford. But to say that laser printing is a sign of a high-end keyboard is a big mistake. In fact, on the contrary, in a keyboard maker's production line, using a laser-printed keyboard is the lowest keyboard. Dachang chose laser printing mainly because of its low cost. Although its production line is expensive, its daily output is more than ten times that of other printing methods, and because it is a burning engraving, it does not require any other. The measures will have a very clear and strong handwriting.

In addition to the cost factor, the use of laser printing on mainstream keyboards is another important reason for environmental protection. For modern enterprises, environmental protection has become a problem that cannot be overlooked. Even if the company’s managers do not consider issues such as public benefits, the environmental protection fees levied by the government will also become problems that they cannot ignore. Compared with ink printing, laser printing has much less environmental pollution. Contamination in the laser printing process is only a trace amount of plastic that burns during the etching process, and there is almost no harmful product other than the faint plastic burning smell in the air. Therefore, in terms of environmental protection, laser printing is an inevitable substitute for ink printing.

However, laser printing has several fatal flaws, which also determines that it cannot be used for high-end keyboard production. First of all, since laser printing belongs to etching and no ink is used, only a single black font can be printed, so that a multi-color overprint design often found on high-end keyboards cannot be achieved; secondly, high-end keyboards are used for design and For durability, most of them use a non-white color design, and add a wear-resistant filler to the keycap material, but due to the laser printing's own characteristics, it makes the keyboard non-white and other fillers added. Can not be etched on the ideal clear handwriting; Finally, the laser printer structural design and programming methods make it best used to create standard key design keyboard, ergonomic and other non-standard structure of the product is difficult to ordinary laser printer Print it out.

Because of this, in the production line of Dachang, laser printing is only used in middle and low-grade production lines to take advantage of its high production speed and low cost; in high-end product lines, due to higher printing quality Requirements, so we can only continue to use the traditional high-cost ink printing method.

2) Screen printing

The principle is to overlay a special screen on a blank keyboard, where the handwriting is hollowed out, and then the ink is scraped from above so that the handwriting will be printed on the hollow part. Screen printing is a low-cost and fast-moving type in ink printing and is usually used for the printing of ultra-thin keyboards such as notebook keyboards.

Screen printing is characterized by the ability to apply a special layer of plastic on the screen after printing the handwriting. After drying, a protective film of plastic covering the writing will be formed, which can prevent long-term use of handwriting. Wear, which is commonly referred to as keyboard overlay technology.

Compared with laser printing, screen printing can print multiple colors freely through repeated overprint of multiple screens, and there is no restriction on the keyboard material requirements. However, due to the limitations of its printing methods, it is still not possible to print keyboards that are too complex in shape.

3) Printing method

The printing method is the most complicated printing technique among the three traditional keyboard printing methods, and is the most traditional and oldest keyboard printing method. The so-called pad printing, that is, the use of a set of letters as the original font type, through the automatic machine after brushing the ink, and then a group of soft rubber block pressed on it, so that when lifting the rubber block, the ink will be transferred Go to the rubber block, and then move the rubber block to the blank keyboard. Press the rubber block and the ink will be printed on the keyboard.

Before the appearance of photosetting technology, books, newspapers and magazines were all printed in this way. Compared with laser printing and screen printing, the printing method is not limited by any printing conditions and can be used to print any type of keyboard. However, the disadvantages of the printing method are also obvious. Its printing speed is extremely slow. Printing a keyboard can almost let more than 10 laser-printed keyboards go down the assembly line. Therefore, except for the small factories that cannot afford laser printers, there is no way to use this type of printing without any technical requirements. Keyboard makers generally only use it to print high-end products that are not cost-effective. Secondly, due to the influence of its printing process, it is much more difficult to apply the film on the keyboard printed by the printing method than the screen printing. Therefore, many keyboards printed using the printing method have not been coated but have studied the composition of the ink. Increase the firmness of the print to enhance the life of the keyboard.

2 New generation of keyboard printing technology

In recent years, with the development of keyboard manufacturing technology, some new printing technologies have emerged. The three technologies described below are representative of a new generation of keyboard printing technologies. Their common feature is that they are dedicated to solving the problem of balance between the firmness and aesthetics of keyboard printing. However, compared with the first three traditional printing technologies, the three new printing technologies are more complex and costly.

1) Laser Filling Method

The principle of the laser packing method is a bit like "tattooing." Tattooing is using a needle to make fine lines on the skin and then painting it with pigments so that the color will penetrate into the lines of the skin and will not be washed away or rubbed later. Drop it. The same is true for laser filling technology. First, use laser printing technology to print the text once (but print lighter than normal laser printing to ensure the smoothness of the surface), and then use the ink printing method for secondary printing, so that the cured ink will be The nicks left by the laser light penetrate into it and remain in it. After that, they will not be easily worn off.

The keyboard printed by using the laser filler technology has overcome the defects of poor laser printing characters and inability to print color due to the secondary printing of the ink, and due to the laser nicks as a basis, the firmness of the keyboard is much higher. In simple ink printing.

2) Thermal sublimation

Sublimation printing is a printing method that is very different from ordinary ink printing. Instead of the common liquid pigment ink, it is a solid resin ink. The ink will sublimate into a gaseous state at high temperature, penetrate into the permeable printing surface in the form of gaseous molecules, and then desublimate, thereby becoming a whole on the physical level with the printing surface, rather than merely “sticky” like ordinary pigment inks. On the printing surface, its printing is very strong. Moreover, resin inks are superior in gloss, morphology and other aspects.

The most common sublimation printing service is the service of ceramic cup “baking” photos. When sublimation printing is used for keyboard printing, the ink will completely “penetrate” into the ABS plastic inner layer of the button, so it is almost impossible to be worn off, and the text of the sublimation printing has a three-dimensional sense and glossiness. However, the process of sublimation printing is much more complicated than ordinary pigment ink printing, and the cost is very high, so currently only RealForce keyboards use this printing method.

3) Scarce text method

This type of printing has so far only been used by Apple Computer on its laptop keyboard, but in fact, this printing method is not uncommon, because although there are few users on the computer keyboard, but the other keyboard - the mobile phone keyboard is almost all used This way printed.

This kind of printing method is very simple to say, is to use the transparent material to make the key, then cover the key surface with the opaque paint, will hollow out the surface according to the appearance of the letter as "Chui Wen." If you apply opaque paint on the side of the keys that does not touch the fingers, the text will naturally become worn. In fact, the main purpose of Apple's use of this type of printing is not to securely write, but to look beautiful. Because this type of hollowed-out font is "engraved", it is clearer and brighter than ink-printed ones. Like the keyboard of a mobile phone, the backlit circuit can be installed under the keys of the hollowed-out text, making the notebook keyboard as unique as a mobile phone keyboard. Good backlighting effect.

However, the shortcomings of the hollow text method are also obvious. When the transparent material is used to manufacture a keyboard, its elasticity, hardness, and wear resistance are inferior to ordinary keycap materials. In fact, no matter whether it is printed with hollow characters or not, the transparent key cap material has so far not been able to catch the traditional black and white ABS plastic on the touch.

Source: "Printing World"

School of Printing and Packaging, Wuhan University Gan Zhaohua Ji Yongqin