Custom Printing: Printing Ink, and Food

You might assume that all commercial printing ink is the same. In fact, both the composition and use of printing ink involve a lot of nuances.

For now, let’s start with two general rules to keep in mind. Printing inks differ depending on the equipment in which they will be used and on the intended use of the printed product.

The technology with which ink will be applied might include offset printing and digital printing, for instance.

Offset lithography “works” because oil and water repel each other. (You can test this for yourself by pouring both water and olive oil into a glass.)

Offset printing ink is an oily substance that is chemically produced to seek the image areas of a printing plate while avoiding the non-image areas, which are coated with water. In an offset printing press, a delicate balance between ink and water allows this to happen.

Only because of this law of chemistry (i.e., the fact that ink and water repel each another) can a commercial printing supplier use printing plates on which the image area and non-image area are both on the same level. (That is, they are neither raised above the surface of the plate, as in relief printing processes such as letterpress, nor recessed below the surface of the plate, as in fine arts intaglio printing.) And only because of the oily nature of offset lithographic printing ink does this process work.

In contrast to the inks used in offset lithography (both in commercial printing and in fine arts printing), the ink in your desktop inkjet printer is water based. The process does not depend on flat (planographic) plates or an oil/water balance. You merely spray the ink onto the substrate through nozzles on your inkjet printer. The process is exactly the same if the inkjet printer in question is a large format inkjet press used to decorate corrugated board and folding cartons.

Food Inks and Toxicity

Inkjet printing is becoming the method of choice for a lot of custom printing these days, including corrugated cartons, flexible packaging, and folding cartons. You can Google these terms for precise descriptions, but for the sake of argument, these are the categories of packaging, and, as noted in prior blog entries, packaging is one of the hottest markets for commercial printing in general and digital printing in particular.

For makeup cartons, presumably, there is little concern about the toxicity of the inks, as long as the product is not ingested and as long as the makeup comes in glass or plastic tubes and bottles contained in the cartons. But for food products that will come into contact with product packaging, it is of vital importance that no toxic chemicals migrate (the technical term) from the printed container or packaging into the food.

There are numerous requirements and specifications for such custom printing inks, and organizations such as the FDA (Food and Drug Administration) publish these requirements for packaging companies and ink manufacturers. Other organizations, such as Intertek (in London), test the inks and certify them as conforming to the safety standards.

HP PageWide Inks

With the preceding information in mind, I received an article from a friend and colleague noting that HP’s T1100 and C500 PageWide presses (and particularly their ink configurations) had been passed by Intertek as being food safe for use in printing corrugated cartons. More specifically, according to the press release from HP, Intertek certified HP as the “first supplier to fulfill the Intertek Guidelines for the Safe Use of Printing Inks” (“Intertek Develops Guidelines for Safe Use of Printing Inks,” HP, 6/20/18).

This is relevant for a number of reasons:

1. 1. HP’s large format digital inkjet printing presses and their inksets have been blessed by a respected standards and testing organization as being food safe.

1. 1. Package printing is a growing sector of commercial printing, and HP is a major player in this arena.

1. 1. In terms of marketing, Intertek’s blessing highlights HP as a trusted vendor. This approval will aid greatly in HP’s potential dominance of package printing.

1. 1. As the first vendor to receive this approval from Intertek, HP has a head start towards becoming the supplier of choice for digital inkjet package printing equipment and also for printing inks (these are not the same thing).

1. 1. Intertek’s approval was based on printed samples provided by HP using its proprietary water-based digital printing inks. To quote from the press release, “Intertek conducted detailed laboratory tests on these prints to measure migration limits and ensure safety requirements in accordance with global regulatory and industry guidance, including Swiss Ordinance, Nestle Guidance, FDA, EU Framework, and others” (“Intertek Develops Guidelines for Safe Use of Printing Inks,” HP, 6/20/18).

1. 1. The specific approval granted by Intertek notes compliance for “printing primary and secondary corrugated packaging, which requires no additional barriers” (“Intertek Develops Guidelines for Safe Use of Printing Inks,” HP, 6/20/18). To put this in context, when you open a box of cereal, you reach in and take out a clear plastic bag containing the flakes or chips. The purpose of this bag is not only to keep all of the cereal from spilling out. It also keeps the food away from the ink (on the outside of the chipboard folding carton).

1. Intertek and similar organizations also test for NIAS. This means “non-intentionally added substances.” What this implies is that when you’re making or printing ink, you don’t always know what other chemicals are produced, whether they are toxic, and whether they will migrate into the food. Therefore, this has to be tested and controlled.

What This Means to You

Mostly I think this is interesting rather than directly pertinent to a designer or print buyer. But it does mean that the closer you get to the supplier, the more important ink certifications will be. If you’re a printer, for instance, you want to make sure all of your inks are appropriate and acceptable, not only for the equipment you’re using but also for the end product, based on its use, and particularly if you’re producing packaging materials that will contain food.

Another thing to consider is that not all inks are the same. Not only are some more appropriate for certain printing technologies (for instance, offset lithography, flexography, thermography, gravure, digital inkjet printing, screen printing, letterpress…), but the final use of the printed materials makes a difference. If a printed product touches food, it has to be safe.

This entry was posted on Monday, June 25th, 2018 at 2:53 am and is filed under Inks. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.