The Printing Press
Its truly a magnificent example of human ingenuity and intuition. An invention that has literally changed the world; leading the onset of mass communication and the ability to share information across the world. With roots in the 1400s and 1500s the printing press came at a time when humanity was struggling through change and helped to usher in large cultural shifts.
The printing press has gone through some dramatic changes over time while still retaining its principles of operation. Modern printing presses print at speeds over 15,000 sheets an hour. Some feed sheets of paper that are 6 feet wide. Certain special applications utilize amazing technologies like ultraviolet and infra-red heater systems, others feed thick stiff materials like boards or plastics. The printing press has come a long way from its roots and there's nothing quite like printing in the 21st century.
The future of printing is bright. Despite some systemic changes within the industry the overall volume of printing worldwide is increasing. Periodically major changes in materials, chemistry, and energy sciences lead to changes in the way things are done in the business of production. New methods and processes bring versatility, reliability, increases in production and increases in safety for operators and our environment. For example new methods of printing conductive ink onto non-conductive substrate allow for the creation of flexible and easily mass produces circuit boards. Industry trends indicate that in some time this new method will be widely adopted and become a major channel of manufacturing printed circuits.
Printing Press Ink
Offset sheetfed printing presses would be nothing without ink. It's the reason the press exists. Good print starts with good ink that performs well in the press and in the press room and printing ink can be one of the largest indicators of overall print quality.
Inks can come in many varieties beyond just the color. Inks can come in different tack and finish. Inks can also come with different additives that can help them to dry more quickly. Ink technology in the 21st century is quite advanced and as time goes on we are sure to see very interesting inks in the future
In convention offset printing there is a constant balance made between ink and water. In the printing process the image is passed by the special chemical properties of the printing plate itself. In some areas it is hydrophobic and in other areas it is hydrophilic. These two terms essentially mean that the plate will attract or repel water. In the areas that are hydrophobic the plate will pickup ink from the ink-train. In areas where the plate is hydrophilic, the plate will pick up water and repel the ink.
The printing blanket has become a staple of the offset printing method. The printing blanket is a smooth mat that is wrapped around a cylinder within the printing unit. This mat acts as a cushion that presses against the master and picks up the image. The purpose of the printing blanket is to transfer the image from the master to the sheet. In other words, the printing blanket is the medium that carries the image from the plate to the paper. Printing blankets are designed to be removed and replaced periodically to compensate for wear.
Printing press powder has long been used in the world of offset printing. It offers numerous benefits in the printing process and is used by almost every manufacturer in the industry. The first and most important purpose of printing press powder is to prevent ink offset. Ink offset is when wet ink from one sheet is transferred onto a second sheet that makes contact. Powder is sprayed onto the sheets as they are stacked at the delivery end of the press, the fine layer of powder forms a microbarrier between the sheets to keep the ink from making contact. A secondary benefit of spray powder is reduced dry time due to a minute air-gap between the individual sheets. This slight gap allows for an amount of air circulation through the stack and give the moisture within the ink a way out.