Flexographic printing, more commonly referred to as “flexo”, has been one of the main types of envelope printing for almost a century.  It was a technological upgrade from letterpress printing which goes back to the days of the Gutenberg press.  Flexography got its name from the flexible rubber plate which it uses to apply the graphic image.

Because of the limitations of the rubber plate, flexo printing was traditionally confined to very basic graphic images:  mostly just type and numbers. However for a return address or reply envelope copy, the quality afforded with flexo printing was more than acceptable for most simple envelope printing requirements.

In the late 1980’s, the invention and practical application of hard plastic (photo polymer) printing plates helped to revolutionize flexographic printing by opening it up to a much larger range of printing possibilities.  These days, flexo printing is routinely used with process printing, halftones, screens and many other fine applications which were previously not possible in that process.

For envelopes, the advantage of flexographic printing stems from the fact that it can be done while the envelope is being made. Many envelope folding machines have built-in printing stations which can apply not only an inside tint (typically printed flexo) but also printing on the outside of the envelope up to two colors.  This “in-line” printing is more economical than printing an envelope on an offset press as a separate process.  Although flexography has come a long way, the type of image that yields acceptable results on this type of equipment is still limited compared to what is possible with offset printing.  The plastic plate just doesn’t hold the image as well as the metal plates used in offset printing. Also, the flexo printing units employed on the folding machines are subject to more “bounce” and variation generally than an offset press.

The more advanced flexo printing mentioned above is done on big, expensive machines that require very large quantities (usually starting around 500,000) in order to be cost-effective. The reply envelopes that you get along with your credit card bill are mostly flexo-printed on these types of machines.

So how do you decide whether flexo printing is right for your job?  The same two criteria that we applied to the offset printing decision process will apply here as well.

Quantity:  In-line flexo printing of the most common variety (1 or 2 spot colors) becomes competitive with offset printing at around the 100,000 quantity level.  That’s where Elite Quality Envelope will generally start quoting if the customer is looking for the best possible price. The cost of the plates and set up time will usually make it less cost-effective at quantities lower than that.  For high-quality, full-color flexo printing, start with the 500,000 quantity as a general rule although some companies will price these jobs competitively at quantities of 250,000 or more.

Quality:  – At Elite Envelope, flexo printing is quoted conditionally “based on suitability following an inspection of the copy to be printed”. Some quotes are so price-sensitive that a customer will want the flexo price only to find out that what they are printing cannot be done that way.  Unless you are printing at the kind of quantities which allow for the state-of-the-art equipment to be employed, any copy with screens, half tones or duo tones, tight registration or fine lines will most likely have to be printed offset.  Some of the decision is based on what is possible and some of it is based on the level of quality that a customer is expecting.  We will generally err on the side of being conservative in our approach as there’s nothing worse than a disappointed customer.

In my next post, I’ll delve into flat sheet litho printing and converting. As always, I welcome your comments!  Feel free to e mail directly at jerry@eliteenvelope.com anytime