Keyboard Key Label Printing Technologies

By Xah Lee. Date: . Last updated: .

The are many technologies for printing the key label on the keycaps.

Pad Printing

Pad Printing is the most commonly used.

Pad printed key wears off after heavy use.

keycap pad printing Dell KB522 keyboard
Pad-printed key labels.

You can easily tell pad printed labels. It looks like a transparent sticker.

keycap pad printing scratched off 08524
pad printed key labels, scratched off.

Almost all Microsoft and Logitech keyboards are pad printed.

pad printing machine for computer keyboard

Laser Marking

keycap printing laser engraved Matias Tactile Pro 3 keyboard
laser charred key labels, Matias Tactile Pro 3 keyboard. 〔photo by Daniel beardsmore.〕

〔►see Matias Mini Tactile Pro Keyboard

〔►see Matias Ergo Pro Keyboard

keycap printing stained laser engraved s
Laser engraved and filled with paint. Note they are stained. 2560×1920 〔photo by Daniel beardsmore.〕

Laser Marked key labels don't wear off, but they have limitations in color, contrast, sharpness. And has difficulty printing filled areas such as Window logo or Apple logo.

There are several techniques using laser to print key labels. They include:

• Laser charring. Using laser to burn the plastic. Basically, burn white plastic into grey labels. This can only be done for white keycaps. And, the label is not high-contrast.

• Laser engraving. Using laser to burn a groove. The groove can be filled with paint. The disadvantage is the infill are easily stained.

laser engraving a keyboard

Dye sublimation

keycap printing dye sublimated IBM Model M 1391406 s
Dye sublimated keycap labels. IBM Model M 1391406 keyboard. 2560×1920 〔photo by Daniel beardsmore.〕

〔►see IBM Model M keyboard, Unicomp

Dye sublimation is a process where heat is used to impregnate a material with a dye. This is different to printing in that printing forms a layer of paint on top of the plastic, whereas dye sublimation causes the dye to sink into the plastic. Dye sublimation was a popular method for keycap printing in the 1980s and 1990s. Because the dye permanently stains the plastic, it cannot be worn off like paint, and unlike laser printing, it can be used to easily print a mixture of different colours.

keycap printing dye sublimated Apple M0116 keyboard s
Dye sublimated keycap printing. Apple M0116 keyboard. 2560×1920 〔photo by Daniel beardsmore.〕

〔►see Apple Keyboards ⌨

Double-shot injection molding

This is considered best, and also most expensive process.

keycap double shot cut
Double-shot injection moulded keycap, cut in half.

Double shot injection molded keycaps are often considered the best type of keycap. Rather than print the legend onto the keycap, the legend is molded from one colour of plastic, and then the remainder of the keycap is molded around it in another colour of plastic. This process has the advantage of producing markings that cannot be worn off, as they are physically part of the keycap. The process also provides high contrast as the legend is not affected by the colour of the surface of the keycap.

Double shot keycaps were de facto standard in the 1970s and early 1980s. However, they are expensive to produce and inflexible (given that a mold is needed for each possible symbol to be printed). Double shot keycaps are typically limited to two colours per keycap; triple or even quadruple shot molded keycaps are possible and have been made, but in most instances, manufacturers used pad printing or dye sublimation for supplemental colours instead of additional moulding stages.

The best-known manufacturer of double-shot keycaps now is Signature Plastics. Other manufacturers include GMK (who now own Cherry's tooling) and Tai-Hao.

keycap printing double shot injection moulded
Double-shot injection moulded keycap. 〔photo by Daniel beardsmore.〕
keycap printing double shot capslock 97186
Double-shot injection moulded keycap. You can see that it's basically 2 layers of plastic of different color. 〔image source

Print in Front-Side of Keys

One excellent method in key labeling is to print the label in front of key.

The advantage is that it won't wear out, as fingers don't touch it.

front print keycap 32102
custom front-side printed keycaps. max keyboard front-side print keycaps

〔►see Keyboards without Numeric Keypad

You can buy keycaps with front-printed labels.

〔►see Where to Buy Keycaps


Many photos on this page are by Daniel beardsmore. Public domain.

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