At some point in your graphic design or print buying career, you may need to print on corrugated board. It will be easier for you to choose an online printing service to print such a job if you understand your options and the custom printing technologies involved.
First of all, what is corrugated board? It is a “sandwich” made of an outer flat sheet of stiff paper, a backing sheet of stiff paper, and “fluting” in between. If you look closely at cardboard cartons (large ones, not shoe boxes), you will see the fluting. The paper seems to snake back and forth like an “S” between the inner and outer flat sheet.
Corrugated board is light and strong due to the fluting. Unfortunately, it can be easily crushed, which can create problems in offset printing due to the heavy pressure of the press rollers in your printing companies’ presses.
So how do you find online printing companies that can print on an easily crushable material? There are at least four options:
Flexographic Printing Directly on Corrugated Board
“Flexo” is a relief printing technique (similar to letterpress in that the image areas are raised) that involves flexible rubber plates and ink. You will see samples in grocery stores. Most freezer boxes and milk cartons are printed this way. It’s also a good technology for printing flat areas of color and simple graphics on cardboard boxes. A flexographic business printing press produces less pressure on the paper substrate than an offset press, so you can print directly on the corrugated board and then convert the flat sheet into a box. To identify flexographic printing on cardboard, look for flat matte inks and large areas of ink (one or two colors), and note that the ink has been printed directly on the cardboard.
Screen Printing Directly on Corrugated Board
Also known as silk screening, this process involves squeezing ink through a metal or synthetic wire mesh by using a rubber squeegie (by hand or on a screen press). Non-image portions of the wire mesh screen are blocked off, or masked, so ink cannot be forced through these areas. By using different screens for different colors and keeping the screens in register (or aligned), a skilled screen printing company can create complex graphics on most surfaces. These include cardboard or corrugated board. Using this technique, custom screen printing vendors can print directly on the corrugated board without crushing the fluting. Then the converter can turn the flat sheets into corrugated boxes.
Offset Printing on Litho Paper, Which Will Be Laminated to Corrugated Board
When you look closely at “point-of-purchase” displays or movie theater “standees,” you will see intricate printed graphic panels that have been glued to the corrugated board. They are noticeable insofar as they have been printed on gloss coated stock, in contrast to the cardboard, which is rough and uncoated. Sometimes you will even see the color bars or registration marks from the offset press.
In this technique, the digital printing company uses an offset press to print four or more colors of ink on the gloss stock, which he then laminates (or glues) to the corrugated board. At that point he can score and fold the board as needed. The quality is substantially higher than flexographic printing companies can provide.
Offset Printing on Flat Board That Is Then Glued to Fluting and a Backing Sheet to Create Corrugated Board
This option avoids the problem of printing directly on corrugated board by having the custom printing service first print the job on a substrate and then add the fluting and backing sheet to actually create corrugated board. Printing companies would only do this for a huge press run. In any other case, the set-up costs would make it cost-prohibitive. This process goes under many names including “preprint.”
So discuss your goals for printing on corrugated board with several traditional online printing services, screen printing printers, and large format printing companies to arrive at the best custom printing option for your job.
This entry was posted
on Wednesday, June 22nd, 2011 at 7:09 pm and is filed under Paper and finishing, Printing.
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