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About Pad Printing

Versatile and complex

What is Pad Printing?

Pad printing is an indirect gravure printing process for marking and decorating a wide variety of products. It consists of a gravure printing plate (cliché), the printing information (print image), the printing ink, the intermediate carrier (printing pad) and the printed material (the part to be printed). The gravure printing form contains the printing information, which is transferred to the printed material by means of the intermediate carrier.

Advantages of the Pad Printing

Printing on curved surfaces

Variety of printing materials

High print image quality

Flexible production quantities

High resistance

Multicolor printing

Low drying effort

Automation

How does pad printing work?

In the gravure printing form (cliché), the image areas are introduced as cavities corresponding to the print image. This means that the image areas are deeper than the non-image areas. These cavities are created using various manufacturing processes. The most common today are by laser and exposure. The cliché is flooded with printing ink and removed with a doctor blade so that the printing ink remains only in the cavities.

The printing ink is transferred indirectly using an intermediate carrier (printing pad). This consists of a flexible silicone rubber mixture and thus enables adaptation to different surface shapes. Printing pads are available in various sizes, shapes and degrees of hardness. The printing pad is pressed onto the cliché and takes the ink from the cavities. In the next step, the printing pad unrolls on the printed material and thus transfers the print image. Thanks to its elasticity, even uneven surfaces are printed.

Standard Pad Printing

Closed ink distributing system

Consisting of: Ink-/doctoring cup, pad printing cliché, printing pad

The ink/doctoring cup combines the function of doctor blade, flood blade and ink well. It is placed on the engraved pad printing cliché. Then, the printing movement starts.

The ink/doctoring cup floods the cliché with ink and at the same time removes excess ink, leaving ink only in the cavities.

The printing pad then takes up the ink (print image) from the cliché in a rolling movement.

The printing pad now delivers the printing ink (print image) in a positive-locking manner onto the printed material in a rolling movement.

Good to know

The "hermetic" system is the most frequently used printing principle in standard pad printing. The doctoring ring of the ink/doctoring cup closes tightly (hermetic) and protects the printing inks better against external influences. Consequently, the printing inks can be used in consistent quality even after a long service life.

Standard Pad Printing

Open ink distributing system

Consisting of: Doctor blade, flood blade, pad printing cliché, clamping wedge, ink well, printing pad

The cliché (with the magnetic plate) is installed in the ink well and clamped. The printing ink is filled into the ink well behind the cliché.

The flood blade is immersed into the ink well and pushes the ink over the cliché during a forward movement.

During the backward movement, the doctor blade pivots over the cliché surface and pushes the excess ink back into the ink well.

Now ink is only in the cliché cavities and can be transferred to the printed material in the next step with the printing pad.

Good to know

The open ink distributing system was used on the first pad printing machines for particularly large printing surfaces. Today, the ink distributing system is only rarely in use.

Rotary Pad Printing

Open ink distributing system

Consisting of: Inking roller, printing pad roller, cliché cylinder, ink well, doctor blade

In rotary printing, the inking and transfer processes run parallel and continuously.

The ink is transferred to the cliché cylinder via the inking roller, which is located in the ink well. A doctor blade scrapes off the excess ink from the cliché cylinder.

During its rotation, the pad roller collects the ink (printed image) from the cliché cylinder and transfers it to the printed material.

Good to know

In rotary pad printing, very large production runs can be realized in a short time, as the printing process is continuous and much faster than in standard pad printing.