11 Printing Technologies On Paper Bags Production

Kraft paper bag has beautiful, low-cost, and eco-friendly features, which is the merchants’ favorite. Except for packaging the goods, one more characteristic of the paper bag is also essential – Brand Promotion. In different printing technologies, kraft paper bags get various attractive appearances. And your Brand Logo and Slogan can get more attention and spreads widely.

When you are purchasing kraft paper bags for your business, it is necessary to take a simple learn about the printing technologies so that you can choose the best type according to your budget and requirements. It will also help simplify the communication between you and your supplier, reduce misunderstanding and save more time.

The Preparation Before Printing

Suppose you want to order a batch of customized kraft paper bags. In that case, you need to offer a design drawing to your supplier for production. The design drawings typically are ai, cdr, or cad file; they are the formats that most printing machines can load. 

The simple printing is based on the CMYK color gamut, not the RGB mode we usually use in our PC and smartphone. Therefore, sometimes the sample products may look slightly different from what you expect, and it’s not the production problem. However, all professional designers and factories will note and deal with it.

Suppose you want your paper bags to be more attractive; in that case, you also need to consider the bag’s material factor. Take the coated paper shopping bag as an example; the gloss or matte sense is hard to show on the electronic design drawing. Therefore, your designer will be better to take a set of Pantone Card for reference and label the color number in the drawing.

Are these things look complicated? Indeed, too many factors that design and printing should consider. What can I do if I just got an idea but don’t know how to express it? It doesn’t matter, JiRong owns a professional design team, all you should do is just tell us your great idea, and we can help you realize it.

After confirming the design, the factory starts composing and prepare the related molds for sample product processing. And the official printing processing will begin after both sides approve the sample.

5 Prepress Techniques

According to the design you provided, the factory will recommend the related printing technologies which can realize the design. They will bring different final effects, and the cost also differs. There are 5 standard prepress techniques:

Flexography

Flexography is also called flexo printing, is the most popular prepress technique. The plate it uses is made from carven photosensitive resin, soft, and can be curved.

Flexography can be applied to almost all paper types or other materials. It got the following advantages:

• Short time cost on making plate;
• Low cost;
• Use safe ink;
• Fast printing speed and high economic efficiency;
• High rate of finished products;

Lithography

Lithography is a relatively tradition printing technology. Its plate is not concave-conveys but smooth and flat. Based on the theory that oil and water don’t mix, the ink is pressed on the paper. Due to this, lithography only can use oil-based ink, which is not safe for the human body. Modern lithography is focused on four-color printing. Even though it works slow, the cost is very low, suitable for the origin color kraft bags simple printing.

Photogravure

The theory of photogravure is straightforward. The plate is made by chemical corrosion, carving, or laser, and the ink will only stay in the sunk places. When the paper going through, will be applied a suitable press and let the ink transfer on it. Its advantages are excellent effect, bright and rich color, and the most important is it has an outstanding anti-counterfeiting function. 

But the photogravure plate-making time is long and has a high cost. Typically, it is suitable for large batch purchases of branding businesses or dealers. With a long-term and stable order, the cost can be reduced a lot.

Screen Printing

Screen printing can be said as the most simple and low-cost technology. Most of the time, it applied to the T-shirt pattern printing. Screen printing is ancient; the plate is made from fabric, synthetic fiber, or metal, the patterns press on the plate through punching. Numerous tiny holds make up the patterns, and ink prints on the paper through the holes, like the Pointillism in painting. It will be the best choice for the kraft paper bag, which only with single color design.

Digital Printing

Digital printing is modern printing technology. We are familiar with it because it is applied to the typical printer in our office. Of course, they are a huge gap between the professional paper product printing machine. Digital printing does not need to make a plate, and you can print the design on the paper directly. It works very fast, and the effect is excellent. 

To the customers, digital printing usually has no minimum order quantity requirement. But its disadvantage is also obvious; compares with the traditional printing technologies, digital printing costs a lot. So it is often only applied to the sample productions or an urgent, small quantity order.

6 Post-press Finishing

After patterns are printed on the kraft paper, there will usually be further post-press processing for a better and unique showing effect. The common technologies are:

Gold/Silver Stamping

Gold and silver stamping is also called foil stamping, is typically applied to high-grade paper products printing, especially shopping bags. A technical term is thermal transfer printing. By heating and pressing, making color foil pressed on the paper, for showing a high-grade metal sense. Most of the time, the Brand Logo on the bags will be gold stamped.                                                                                                                                       

Laminating Filming

Laminating filming makes the paper surface smoother and brighter. It processes by hot-press a transparent plastic film on the paper and creates a water and proofing effect. The patterns also become brighter and the surface stronger. But due to plastic is nondegradable and challenging to recycle, so it needs more considerations. Another, the laminating film is also classified into matt lamination and bright lamination.

Waxing

It is usually applied to food-grade kraft paper processing. Edible wax will be cover on the kraft surface by heating, and it creates certain water and grease proofing effects.

UV Varnishing

UV varnishing is the frequently-used further processing method of screen printing and lithography. It lets the ink dry quickly and creates a more unique appearance(such as brighter) by UV irradiation.

Embossing

Embossing is typically applied to thicker kraft paper or cardboard. By using pressure, making the patterns on the plate showing on the paper; the appearance has a sense of three dimensions.

Die-cutting

Cutting by mechanical or laser, carving the patterns on the paper directly. Many gift bags and boxes will take this processing. And more we can see are the die-cut handles of the paper bags.

All above the post-press processing methods usually can be used to overlay each other, to reach a more attractive looking.

Final Processing

The paper after printing processing will be transfer to the other machines for further processing. They will be through cutting, sticking, adding handles, etc., finally making into the finish products.