Silk Screen Printing

As A Good China packaging box supplier, CHINA BBP CO., LTD supplies the custom paper box with the silk screen printing. This printing technique is usually used on the corrugated mailer boxes, folders, kraft paper box, blackboard box and some other printed paper boxes made of the specialty paper.

The custom paper box below is a silk screen printed book mailer, which is printed inside and out.

Custom paper box with the screen printing

What is Silk Screen Printing?

In Screen printing, a screen mesh is used as plate to transfer the ink to the targeted printing area of the paper box. Meantime, the blank area on the paper box remains blank by applying an impermeable coating on the mesh to prevent the inks from passing through. A blade or squeegee is moved across the mesh to force the ink into the small opening first, then the ink is transferred to the paper box by a momentary touch. One color is printed at a time, so several screens can be used to produce a full color printing paper box.

The screen printing is also referred to as silkscreen printing because silk was used initially to make the mesh at the early stage. Afterward, polyester was invented to replace the silk to improve the printing quality and to reduce the cost. Currently, the polyester is the most popular mesh in general use. Other materials include nylon and stainless steel. In the printing of the custom paper box, the mesh size is an important factor, which will determine the outcome and look of the finished design on the material.

The screen printing process on the custom paper box

The Process of the Screen Printing

The screen printing consists of 2 main steps, prepare the screen mask, then do the printing.

• (1)A screen mesh is stretched across an aluminum or wooden frame that matches the size of the printed paper box.
• (2)A coating of photosensitive substance is applied on the screen mesh.
• (3)A positive mask is used to cover the parts to be printed such as the texts and images, and then the screen mesh are exposed to the UV light. The coating on the blank parts not to be printed become hard.
• (4)When the screen mesh is flushed with water, the coating on the printing part is washed away.
• (5)Once the mesh is dried and inspected, the screen mask is complete.
• (6)The screen mesh is placed on top of the paper box to be printed.
• (7)The ink is applied across over the screen and the ink passes into the small openings on the mesh.
• (8)The mesh touches the surface of the paper box momentarily and transfers the ink to the paperboard by moving a blade or squeegee across the mesh.

Vantage Point of Screen Printing

Because the ink is forced to pass through the openings on the screen mesh to transfer the image during the screen printing process, the ink layer on the paper box would be quite thick. It means that the screen printing can be applied on any kinds of paperboard, thick or thin, glossy or matte, with a smooth or rough surface.

Custom Screen Printed Paper Box

In DE Printed Box, 90% of our paper boxes are litho printed, or UV printed. But when we come to a custom paper box made of a thick paperboard, like black specialty paper or kraft paperboard, those printing methods don't work any more because the inks layer is too thin to be visible. For these special paperboard, we usually use the silk screen printing method to do the printing.

Custom Screen Printed Paper Box

As you can see, the book mailer has the pantone white color printing outside on the kraft paper and the pantone blue color printing inside on the white kraft paper.

More About Screen Printing

Screen printing is arguably the most versatile of all printing methods. It can be used to print on a wide variety of substrates, including paper, paperboard, plastics, glass, metals, fabrics, nylon, cotton and many other materials. Some common products from the screen printing industry include custom paper boxes, posters, labels, decals, signage, and all types of textiles and electronic circuit boards. The advantage of screen printing over other print processes is that the press can print on substrates of any shape, thickness and size. In DE Printed Box, we usually use the litho offset printing process to create the high graphic printing on the custom paper boxes, but it doesn't work on some paper materials. Then we use the screen printing.

A significant characteristic of screen printing on the paper box is that a greater thickness of the ink can be applied to the paperboard than is possible with other printing techniques. This allows for some very interesting effects that are not possible using other printing methods. Because of the simplicity of the application process, a wider range of inks and dyes are available for use in screen printing than for use in any other printing process. Actually, the spot UV finish on the paper box is applied through the screen printing process due to its special thick coating characteristics.

Utilization of screen printing presses has begun to increase because production rates have improved. This has been a result of the development of the automated and rotary screen printing press, improved dryers, and U.V. curable ink. The major chemicals used include screen emulsions, inks, and solvents, surfactants, caustics and oxidizers used in screen reclamation. The inks used vary dramatically in their formulations (GATF 1992b).