Digital color printing on the way to offset quality
By Andrew Tribute
Digital production color printing, which is printing on a digital press using dry or liquid toners instead of ink, is now more than 10 years old. The first machines from Indigo and Xeikon were first seen at IPEX in 1993, but it was at Drupa in 1995 that they really first became available. At the same drupa, Heidelberg introduced its new Quickmaster 46-4 DI press that also worked from digital data, but which output using four-color offset printing. This product could be said to have slowed down the acceptance of digital color presses because of its better and more acceptable quality, and lower priced operation.

The earlier digital color presses suffered from a number of problems that restricted the type of work they could do well. They could produce excellent color images, although there were certain faults. Tints often did not print well showing streaking or banding. Some colors would not print accurately. There were also restrictions on the types of paper or other substrates that could be used. Despite this, many organizations invested in the products and produced a range of excellent work. The benefits were that very short-run work could be produced economically in color. A few organizations also found that personalized printing could be done where prints were individually personalized for the end user.

After 1995, the market developed rapidly. Both Indigo and Xeikon enhanced their products to give higher quality, greater reliability, and lower operating costs. Toward the end of 1999, Xerox introduced its DocuColor 2000 series of digital presses that had higher performance and lower cost with excellent quality. The DocuColor 2060 rapidly became the largest selling of all digital presses. Canon also came to market with its CLC 1000 that also sold well. While all these products produced excellent color, in particular Indigo with its newer Turbostream model, output did not really look like offset. The colors while bright were somewhat harsh. When the printed image was looked at from an angle it had a sharp reflection. The image also felt somewhat proud of the paper as the toner essentially sat on the surface of the paper not in the paper like with offset. This was particularly the case with the dry toner machines were the individual particle size of the toner was quite large.

Digital color becomes well accepted
At Drupa 2000, digital color printing was becoming well accepted and there were more than 10,000 machines installed around the world. At Drupa, there were also the first indications of the next level of developments we could expect to see in the future. In order for the commercial print market to really start using digital color presses, they needed to produce output that looked like offset printing. The technologies to make this happen have been developing rapidly, and the press manufacturers have learned how to produce this higher level of quality. Since Drupa 2000, some new machines have come to market, which do produce output that is very like conventional four-color offset. In many ways it is better than four-color offset. This is because the color gamut of CMYK toners is better than that of offset inks. This means a digital press can produce a wider color range than a four-color offset press.

Toner printing will look like offset
At Drupa 2004, digital color printing will challenge four-color offset printing in many areas of commercial printing for run lengths approaching 3,000 impressions. The presses that will probably draw most attention as being “offset-like” will be Heidelberg’s NexPress 2100, HP Indigo Press 3000 and Xerox’s DocuColor 6060 and iGen3. In the case of the Heidelberg and Xerox units, the presses achieve their levels of quality through use of finer toners; almost contact free transfer of toner from the intermediate surface to paper; and slower and lower temperature fusing of the toner to paper. In terms of the HP Indigo units, they can be very much like offset and can go beyond the other manufacturer’s products and many offset presses in terms of color gamut as they use six or seven colors rather than four. They do have a problem, however, in that they don’t print so well on lightweight or uncoated papers.

Digital color printing has been striving to become like offset since it was first introduced more than a decade ago. The look and feel of offset printing is the standard for commercial color printing and is what print buyers expect. Visitors to Drupa certainly will see the offset-like quality from the presses mentioned above, but it is also likely show attendees may see it in other products as well. I fully expect to see Canon bring in a new press that will have much better quality than the presses it currently produces.

“Digital color lite” printer for low cost entry
There has been a major development in digital color printing in the past year, and this has been referred to as “Digital Color Lite.” There have been a number of Japanese suppliers that have introduced new products that print slightly slower than the production level printers already mentioned, and which show excellent color quality. Most of these printers run at around 30 pages/minute, and cost well under 50,000 Euro (50,000 Euro is equal to about $63,325). In the case of a few of them, they have a new development in color toners. These are new toners created chemically rather than being ground down from a large block of toner material. The toners can be created in much smaller and cleaner shaped particles, and also can flow together more easily. This latter facility means that the oil that is used with conventional toners can be substantially reduced. Reducing the oil, or developer, as it is known, means the print does not have such a gloss effect and is more like ink.

Currently, chemical toners are used in machines from Konica and Xerox in this area of the market. They are not as yet found in higher speed machines.

Printers should look at these “Lite” machines very seriously as these may be their competition in the future. With the high, almost offset-like quality they can produce, printers can expect to see them being installed by creative companies and by corporate in-plant print departments to produce a range of color work up to 200 impressions. This is work that up to now is given to external printers. Because of the high level of quality set-up and control in these machines generated by their digital front-end units, mainly supplied by EFI, they will make color almost a commodity product.

Comparing cost is vital
One of the key factors printers will be concerned about if they are planning to get into digital color printing, either to complement or compete with offset printing, is the cost. This is both the purchase cost, but above all the running costs of the equipment. In most cases, the costing of a digital press is very different from offset. Most suppliers will only offer what is termed a click option. That is every time a print is made a “click” payment is made to the equipment supplier. This may cover the total running cost, including the toner, but there normally will be a charge to cover all maintenance, spares and support. In these cases, toner is charged additionally. Heidelberg with its NexPress works differently and charges for toner, support and parts, as they are required. In other words — like an offset press. They have made most of regular maintenance and service operations of the NexPress operator tasks. It is not really like offset though as major parts need replacement at very regular intervals. For example, it is recommended that the imaging drums with their organic photo conductors, and the transfer drums, be replaced around every 250,000 impressions. This means every week for a heavily used machine. With a click-based machine, this is included in the click price. For owners of a NexPress, this means the machine owner pays for these items. If companies are evaluating purchase of a digital color press, they need to fully understand the different charging options. Whichever way it is with modern production presses, the operational costs for a high-volume machine allow it to be competitive with offset possibly up to as much as 3,000 impressions. These crossover points are very difficult to calculate and many experts have very different opinions on this subject.

Inkjet provides many applications
Finally, digital color printing at Drupa will cover much more than the items covered in this paper. We will see very high volume low-cost per-print color from Scitex Digital Printing with their presses. These use continuous inkjet technology and can achieve speeds of up to 2,000 four-color impressions per minute. With their latest print heads, color quality is close to that of newspaper offset printing. For many markets this may be very interesting. Also in the inkjet area, this time using drop-on-demand technologies there will be a wide range of presses that compete with offset and screen printing for display work. In fact, much poster and display work has already switched to this digital color technology. Inkjet printing will also be seen in short-run carton making applications where it challenges offset printing. It will also been seen in the industrial printing market for handling of laminate and flexible packaging printing from Dotrix and The.Factory, and in this case it is replicating gravure quality.

Drupa 2004 will be the place to come to look at the current state of all forms of digital color printing and to asses whether the technologies are yet challenging the established printing processes in terms of quality and cost. It will be one of the most interesting aspects of what is going to be a very exciting event.

About the author: Andrew Tribute is managing partner of Attributes Associates and is an editorial contributor for Seybold Publications Inc. He has been in the printing and publishing industry since 1964. From 1985 until September 2000 he worked with Seybold as its international editor. He is a regular speaker at conferences on a global basis, as well as speaking at many of the major international trade exhibitions. He also writes a monthly syndicated column that is published by many of the key international printing magazines throughout the world including Deutscher Drucker. He is also a Fellow of the United Kingdom’s Institute of Printing.