With the advent of relatively inexpensive plate exposure devices in the mid-2000s, the popularity of Computer-to-Print machines, where each print unit was equipped with a separate laser head, began to decline.

It should be recalled that such machines had been developed by both Heidelberg and a number of other equipment manufacturers since the late 80s with the aim of stabilising quality and reducing the impact of dampening on the printing process.

With the plate making process stabilised and easy to calibrate, it was time to get to grips with the ink machine.

How printing machines have changed over the last 30 years

My thesis at the University of Printing was to investigate the effect of the inertia of an inking unit of classic printing machine with different ink capacities when increasing and decreasing the ink. The printing machine should have not be have any characteristic curves and any electronic interference in the printing process. During the print run we increased the ink supply and measured with a densitometer how many sheets the machine would reach a stability. In general, after the change in ink adjustment, the Adast Dominant from the late 80s was achieving stability in 150 sheets. The Planeta Varimat – in 300 sheets, and the 1995 GTO 52 – in 80 sheets.

All this points to the imperfection of the colour machines of those years. That’s why all machine manufacturers were actively engaged in reducing changeover costs, namely reducing the number of sheets rejected during changeover.

Both technologies – KBA Gravuflow and Heidelberg Anicolor – were 2000s attempts to improve on traditional offset for small runs, but the working principle was different.

While Heidelberg worked with Presstek to develop machines each with its own CTP, Koenig & Bauer took a different route. They decided to reduce the number of sheets per changeover by rethinking the design of the ink unit of the printing machine in principle.

 

KBA Gravuflow: design and history

KBA Gravuflow is a waterless offset technology developed by Koenig & Bauer (KBA) in the 1990s. Unlike traditional offset, it used an anilox roll to precisely dispense ink, which ensured high colour stability and eliminated the need for a dampening solution.

Gravuflow was first introduced at DRUPA 2000 in the KBA Rapida 74 G machine. Four years later, at DRUPA 2004, the compact KBA Genius 52 machine was shown, also using Gravuflow.

Unfortunately, after a quarter of a century, there is little information about this technology. But I have in my possession a KBA Process magazine from 2005, when dry offset technology was in its heyday.

 

How does the Gravuflow press work?

The main difference between the KBA Gravuflow and conventional offset is the absence of zonal ink adjustment. In conventional offset, the ink is fed through zone screws that adjust the layer thickness manually. In Gravuflow, this process is eliminated and that is why more precise.

The main design elements are:

1. Anilox roller (engraved roller)
   • It has a surface with microcells that hold the colour.
   • The number and depth of the cells determine the thickness of the paint layer.
   • Allows the delivery of a precisely metered amount of ink to the printing plate.
2. Chamber doctor blade system
   • Excess ink is removed from the anilox roll by a special doctor, leaving only the exact amount of ink in the cells.
3. Printing plate
   • Waterless offset plates are used, similar to those produced by Toray.
   • Unlike conventional offset, it does not require adjustment of the moisturising solution supply.
4. Offset cylinder and printing cylinder
   • Classic offset scheme: ink is transferred from the plate to the offset cylinder and then to the material to be printed.

Evolution of Gravuflow on different machines

KBA Rapida 74 G (2000) – the classic Gravuflow

Features:

• Full-format offset machine ( 50×70 cm format ).
• Used an anilox roller for ink delivery as in gravure printing.
• Supported fast plate change.
• Designed for medium runs (from 500 copies) where standard offset was inefficient.

Themain problem was the high cost of waterless plates and the difficulty of handling high runs.

KBA Karat 74 (1995-2002) – a joint project with Scitex

Features:

• One of the first DI (Direct Imaging) machines where plate exposure took place right inside the machine.
• Used Gravuflow for precise ink metering.
• It was oriented to digital offset, but did not become widespread.

Main disadvantages were high price and difficult maintenance.

KBA Genius 52 (2004) was the latest evolution of the Gravuflow

Features:

• Compact offset machine for 52×36 cm format .
• Completely waterless printing (analogue to Presstek DI technology).
• Used Gravuflow with anilox rollers on each colour machine.
• It was characterised by ultra-short set-up – only 5-10 sheets of waste.
• It supported printing on non-standard materials (plastic, cardboard, metal).

Genius 52 did not become a standard due to the high price of equipment and consumables. In addition, competition from digital machines (HP Indigo, Xerox iGen) increased in the late 2000s.

 

Why did Gravuflow disappear from the market?

Despite the technical advantages, the technology did not become widespread for a number of reasons:

1. Thehigh cost of plates and inks – waterless plates were more expensive than conventional plates, and the inks required special conditions.
2. Difficulty working on large print runs – waterless offset overheats and is unstable for long printruns.
3. Development of digital printing – HP Indigo, Xerox iGen machines made waterless offset less popular.
4. Competition with Anicolor – Heidelberg Anicolor, introduced in 2006, proved easier and more efficient for short runs.

Today, Gravuflow is only found on used KBA Genius and Karat machines, but active use of this technology stopped after the 2010s.

 

Heidelberg Anicolor: design and history

 

Anicolor technology was developed by the German company Heidelberg and introduced in 2006. This curious offset printing technology appeared on Speedmaster SM52 machines with a short inkjet. It combined the advantages of offset and digital printing, offering high quality and fast changeovers.

History of the Heidelberg Anicolor

Prior to Anicolor, Heidelberg had developed traditional offset machines, but these had the serious disadvantage of high set-up times and materials, especially for small runs. The company was looking for ways to reduce the cost of switching from one order to another, as the market in the early 2000s began to demand shorter runs, faster turnaround times and minimising waste.

Anicolor’s main objective was to:

• To reduce makeready times to less than 10 sheets (instead of 100+ in traditional offset).
• To eliminate the use of complex zonal ink supply adjustments.
• To achieve high colour consistency and print accuracy with minimal human error.

The use of a single rasterised anilox cylinder in each ink unit solved many technological problems simultaneously. In 2007, in the Vetter beer hall in Heidelberg, we crossed paths with Anton Dyuzhenkov, the owner of the printing house ‘Colour Formula’. It was the first in the CIS countries to purchase a four-colour machine with Anicolor. Anton spoke enthusiastically about the test results and claimed that the machine was completely devoid of the disadvantages of the classic printing process. He came to do tests on the new machine before the purchase and prepared an incredibly complex test plate, which a printing machine with an ordinary colour machine would never have coped with.

Results of printing test

Firstly, the machine was completely devoid of templating problems. Anton placed on the sheet on one side large sealing surfaces with small white space elements inside. And on the other side – a small control element on a blank sheet, which had to have a higher optical density.

Secondly, the machine has no local adjustment screws for the ink zones. All surfaces of an Anicolor printed sheet have the same optical density. It is possible to change the overall adjustment of the ink supply by changing the viscosity of the ink by increasing or decreasing the temperature of the rollers, and this within a range of 10 per cent. Thus we can say that the printing process is strictly standardised.

Thirdly, plate output is handled by a conventional CTP device, which only needs to be calibrated once. After that, the human influence on the printing quality ends.

Fourth, the first generations of the machine were only capable of CMYK printing. After 2008, mixed ink printing was introduced, and after a few more years Anicolor appeared on the Heidelberg XL75 machine.

 

Competitors before the introduction of Anicolor

Before the advent of this technology, Heidelberg’s main competitors in the short run segment were:

1. Traditional offset machines (Komori, KBA, Ryobi, Manroland)
   • Characterised by high colour stability and low production costs for large runs, but inefficient for small orders due to long set-up times.
2. Digital printing machines (HP Indigo, Xerox iGen, Canon, Konica Minolta)
   • Allowed to print from one copy without set-up, but were inferior to offset in quality, cost on medium runs and variety of materials to be printed.

Disadvantages of competitors to Anicolor

• Conventional offset required significant setup and colour correction costs.
• Digital printing offered less choice of papers, inks were less durable and the cost of production was higher for medium runs (500-2000 copies).
• Hybrid systems (such as Heidelberg Quickmaster 46-4 DI, Speedmaster SM74 DI, Ryobi 3304 DI) with laser units in each unit, although they reduced set-up time, were still inferior to Anicolor in terms of speed and economy, while Presstek polyester plates were also inferior in terms of quality.

Advantages of Anicolor

1. Minimal makeready – 6-10 sheets of paper per makeready.
2. Automatic ink feed adjustment – no complicated zoneadjustments.
3. High colour stability – perfect colour from the first print run. Offset printing could now be free of human error, calibrated and standardised.
4. Cost-effective – the cost of printing is similar to traditional offset for medium runs. But Anisolor is able to quickly print short runs of 50 or 100 sheets, which would be unprofitable for a conventional offset printer.
5. Compatible with classic offset papers – without the limitations of digital printing.The SM52 sheet feeder is the sheet feeder of a conventional press, capable of printing up to 15 thousand sheets per hour.

 

 

Key differences between KBA Gravuflow and Heidelberg Anicolor

	KBA Gravuflow	Heidelberg Anicolor
Type of Printing	Waterless Offset	Water Offset with short inking unit
Working Principle	Uses an anilox roller and an ink metering system through engraved cells	Uses an anilox roller but without zone control of the ink supply.
Colour stability	High, as there is no dampening solution	High, due to even and uniform colour distribution
Set-up	Low set-up costs	Low set-up costs (6–10 sheets)
Disadvantages	Requires special Toray waterless offset plates and special operating conditions. Inks are more than twice as expensive as conventional inks and are very rarely available	More expensive than traditional offset, but cheaper than digital technology for medium runs

 

Anicolor was a major step forward, occupying a niche between offset and digital, allowing printers to handle short to medium runs without sacrificing quality and at a lower cost.

It is worth noting that the technology still exists today. The Heidelberg XL75 Anicolor machine was still on display at DRUPA 2025.