The story of the first Heidelberg K-offset machine is almost a detective story. But it is very telling because this story is repeating again today.

It is an interesting fact that today Heidelberg is known as the undisputed world leader in sheetfed offset machines. But the fact remains that of all the major players in the market, this company was the last to come to the production of offset machines….

 

When everything in life seems just as it should be
At last success seems just around the door
Don’t forget boy,
Look over your shoulder,
Cause things don’t stay the same forever anymore

(Alan Price. Look Over Your Shoulder. 1971)

I put the verse of this famous song in the epigraph for a reason. History is always in a spiral. It is human nature to bathe in the rays of glory, not noticing that the world has already changed, and soon someone else will take all your achievements. The age of digital printing is coming, and manufacturers of ‘classic’ products should always look around to make sure they don’t fall by the wayside very soon.

In the previous chapter I did not simply describe the personality of Mr Hubert Sternberg. In order to make the story complete, I needed to start with him, to show his importance and influence on European printing, before we get to the machines themselves. I have always been interested in a coherent story. All the more fascinating is the process of following the entire path the company has travelled before it revealed the next high-speed solution at DRUPA 2024.

It was the late 50s. Europe was beginning to recover from the effects of the Second World War. The Schnellpressenfabrik from Heidelberg, a company we know, managed to maintain production and even expand it, despite the recommendations of the occupation authorities. A great deal of equipment was destroyed during the war and a lot of it was taken away as reparations. The booming economy demanded more and more equipment, which was immediately incorporated into production.

Schnellpressenfabrik had a huge advantage – the equipment was reliable and easy to use. In its own way, the city of Heidelberg was also lucky: it was not destroyed during the war, unlike neighbouring Mannheim. The factory also remained intact, and it was only thanks to Mr. Hubert Sternberg’s own active opposition that it was not closed down and exported to Eastern Europe as reparations.

The equipment itself did not need to be improved – letterpress technology had been perfected. It would seem that the plant should just produce machines, meet the huge demand in the market, and not think about the future. The machines sold at such a rate that very soon the question of expanding production arose. Since development in Heidelberg itself was not possible due to lack of space, a site 15 kilometres away, in the village of Wiesloch, was purchased. One can only imagine what this meant for post-war Germany – in 1957 the new plant was commissioned and the number of employees rose from 850 to 5,000 in just a couple of years!

Thus, in the second half of the 50s, Schnellpressenfabrik Heidelberg became the undisputed leader in the production of letterpress printing equipment – a direction it had followed for the last hundred years of its existence.

And this is where the fun begins.

By the late 1950s, offset lithographic printing had begun to become more popular due to a number of advantages. It allowed printing on a much wider range of different papers at high speeds, and most importantly, the cost per impression on long runs was much lower. Offset plate production technology still had a long way to go through the invention of a durable copy layer, bimetallic and trimetallic plates, but the trend was there. The new way of printing left little chance to traditional letterpress printing with its casting of lines on linotype, with time-consuming and expensive production of clichés, and with extremely complex process of screening and printing of full-colour works from these clichés.

And now imagine such a force majeure: our hero, a factory from the city of Heidelberg, has just invested in new production. In 1957, the first DRUPA exhibition took place, at which the company found triumphant success and once again made itself known in Europe, America and even the Middle East. And at the same time, a completely new technology in which the company had no experience at all, was just around the corner!

Hubert Sternberg was adamantly opposed to the development of a new machine. In his opinion, it was necessary to squeeze everything out of letterpress printing – to improve the existing technology, in which they were the undisputed leader.

At the highest levels of management, Sternberg had loyal associates. Mr. Arthur Büttner was Chief Designer, and they shared almost 50 years of experience at Schnellpress. It was Büttner who led the development of the T-platen and the OHC cylinder press. Rotary presses using relief plates had recently been added to the Schnellpress armoury, but marketers researching the market already realised that letterpress printing would soon be in severe decline. One of those who had the experience and realised that the future lay in offset was Mr. Willy Jeschke. He joined Heidelberg from Faber & Schleicher (lated MAN) in 1956. He was soon joined by Dr Wolfgang Zimmermann, and the youth was to make Herr Sternberg make a radical decision – to build an offset printing machine!

The photo shows the ‘classic’ Heidelberg OHZ letterpress machine, which was later produced under the acronym SBG. Remember what it looked like. So that the CEO would not suspect anything, it was decided to develop the new model in secret. The young managers were taking a big risk: if the new machine failed, they would be dishonourably dismissed. But if they succeeded, it would define their careers for many years to come. Looking ahead, that’s exactly what happened.

The new Heidelberg K-offset machine should be similar to the ordinary ‘black’ machines.

Legend has it that Hubert Sternberg was unaware until the last minute what kind of new model the new designers were developing. On frequent visits to the workshop, he saw a machine similar in outline to the classic Original Cylinder. But it was a very different machine.

Taking an existing KRZ rotary model, the engineers quickly modified it into Heidelberg’s first offset printing machine. Called the KOR, or Klein Offset Rotation, the model with a sheet size of 40 x 57 cm was introduced by Hubert Sternberg just before the DRUPA 1962 exhibition. How the young developers managed to keep the new machine a secret – I would be interested to know that myself. But outwardly the machine was aptly similar to the company’s usual stop-cylinder machine, and at a cursory glance one could hardly suspect a novelty that would define the company’s development for decades to come.

Everyone expected Herr Sternberg’s anger, but against all odds, everyone liked the machine at the exhibition. The new machine outshone all new developments in letterpress printing, and within a week an incredible number of contracts were signed for the new model.

The machine proved to be so simple, reliable and high quality that after a minor redesign in 1965, the K-Offset remained in production until 1986, when by the time it was completed, some 40 thousand machines had rolled off the factory in Wiesloch, Germany.

 

What technical ideas were used in this machine?

Now it’s time to talk about the machine itself. The Heidelberg KOR offset printing machine incorporated several key technical ideas and innovations that contributed to its success. These ideas were both to improve print quality and to increase the productivity of the machine. Here are some of them:

1. Compact design

The Heidelberg KOR’s printing unit was not vertically positioned, as in modern machines, but… horizontally. The machine was surprisingly easy to maintain – to wash the rollers, to set the plate, to load paper. It was a bit difficult to change the rollers, but this procedure was not done very often.

The machine was not as bulky as competitors’ machines of the time. It was designed for customers who had previously been crucible and OHT customers, and the new machine would not intimidate printers with its unusual design. The compact design also shortened the path of paper in the machine, making it less likely to wrinkle and improving print quality.

2. Short offset unit

One of KOR’s main innovations was the ‘short offset unit’ (Kurz Offset-Rotation), which gives the model its name. The idea was to minimise the distance between the pressure point of the plate and offset cylinders and the next pressure point of the offset and impression cylinders. The dampening solution had time to evaporate from the surface of the offset blanket after emulsion separation.

3. Easy color jobs printing

The machine used an absolutely new ink unit, which provided more even ink distribution over the surface of the printing plate and therefore better print quality.

The Heidelberg KOR offset printing machine used a plush cloth dampening that was traditional at the time. This type also known as tandem dampening unit. This technology would survive until 1995, when Heidelberg completely abandoned plush rollers in favour of Alcolor technology.

4.  Process automation

The next generation of the KOR included elements of automation, which was a new word in technology at the time. The machine was equipped with systems for automatic sheet delivery control. Automation also allowed the machine to be set up more quickly for different print runs and types of work.

5. Resistance to wear and tear

Many Heidelberg printing machines have survived to this day thanks to one very important feature:

The company has always paid great attention to the quality of materials: the machine may cost more, but the daily maintenance will be cheaper.

This has always been the case, and I hope it will continue to be the case in the future. The KOR machine was one representative reflecting this ideology. The machine used wear-resistant materials for key machine components such as cylinders and rollers. This technology ensured the longevity of the equipment and reduced the need for frequent repairs. While no one can remember the names of the machines produced by competitors, this KOR model is still in operation in many print shops.

6. Versatility of use

The Heidelberg KOR was designed to be a versatile machine, capable of handling a wide range of paper sizes and types of work. This included the ability to print on thicker and thicker materials, making it suitable for a variety of applications, from conventional books and magazines to packaging.

7. Integration with traditional letterpress printing

The new series matched the format of other Heidelberg machines. It had the same feeder and delivery that the printer was accustomed to. The machine could therefore be used in combination with traditional letterpresses. This was important for printers who were adopting new technologies but were not yet ready to completely abandon the old printing methods.

8. Ease of maintenance

The machine was designed to be easy to maintain and minimise downtime. The designers paid attention to easy access to the main components and their quick replacement. And access is really easy and convenient!

These and other technical ideas allowed the Heidelberg KOR to remain on the assembly line for 25 years, and to become one of the most successful offset printing machines of its time.

 

Main Specifications:

Heidelberg KORD (Kleine Offset-Rotation)

1. Print format:
   • The standard sheet format for KORD is 360 × 520 mm.
   • The maximum print plate format is 370 × 540 mm.
   • The minimum sheet size is approximately 100 × 180 mm.
2. Performance:
   • Printing speed – up to 6,000 impressions per hour, which made it quite productive for its time.
3. Number of colours:
   • One print unit only. Multi-colour printing required multiple passes of paper through the machine.
4. Dampening system:
   • The KORD model used a separate dampening system like the original KOR, which ensured a stable printing process.
5. Automation:
   • The model was equipped with a number of automated features, such as automatic paper feeding and an ink control system, which greatly simplified the operator’s work.

Heidelberg KORS (Kleine Offset-Rotation Standard)

The Heidelberg KORS was a modification of the KORD with an expanded print format.

Key features:

1. Print format:
   • The standard sheet size for the KORS is 460 × 570 mm, which is slightly larger than the KORD.
   • The maximum print plate size is 450 × 570 mm.
   • The minimum sheet size is similar to KORD, approximately 100 × 180 mm.
2. Performance:
   • Printing speed is also up to 6,000 impressions per hour.
3. Number of colours:
   • Like the KORD, the KORS was a single-colour machine. The larger format made it better suited to producing complex jobs.
4. Dampening system:
   • A separate dampening system was also used.
5. Automation:
   • The KORS model also had automated features similar to those used in the KORD.

 

What other offset printing machines were on the market at that time?

Although offset transfer lithographic printing had been known for over a hundred years, it was used in art. But in the mid-1950s, however, several models of printing machines appeared on the offset market that forced Heidelberg to think seriously:

1. Roland Favorit (Roland Offsetmaschinenfabrik Faber & Schleicher)
   The Roland Favorit was one of the first successful offset printing machines produced by Faber & Schleicher. This machine became popular due to its reliability and print quality.
2. Harris Intertype
   Harris (later Harris-Seybold) was an American company, one of the first to produce successful commercial offset machines. Harris Intertype produced various models for web and sheetfed offset printing, which were widely available on the market.
3. Miehle Vertical V-50 (Miehle Printing Press & Manufacturing Co.)
   Miehle was known for its high quality printing machines. In the 1950s, it began producing offset printing machines such as the Miehle Vertical V-50. It became popular for their performance and accuracy.
4. Davidson Dualith
   The compact offset printing machine manufactured by Davidson was widely used in small print shops and for commercial printing. These machines were known for their affordability and ease of operation.
5. Solna 125
   Solna, a Swedish company, was known for its small and economical offset printing machines. The Solna 125 was one of the first models to be recognised for its compactness and affordability.

Success of these machines contributed to the growing popularity of offset printing, which gradually began to displace traditional letterpress printing.

To conclude, I want to bring a video showing how comfortable the machine KOR was to use. There are still companies that know and love this machine. Even though more than 40 years have passed since it was discontinued.

 

Pictures taken from https://www.boggsequipment.com/ and British Letterpress