Rotary printing press
A rotary printing press is a printing press
Printing press
A printing press is a device for applying pressure to an inked surface resting upon a print medium , thereby transferring the ink...

 in which the images to be printed are curved around a cylinder. Printing can be done on large number of substrates, including paper, cardboard, and plastic. Substrates can be sheet feed or unwound on a continuous roll through the press to be printed and further modified if required (e.g. die cut, overprint varnished, embossed). Printing presses that use continuous rolls are sometimes referred to as "web presses". Rotary drum printing was invented by Richard March Hoe
Richard March Hoe
Richard March Hoe , was an American inventor who designed an improved printing press.-Biography:Hoe was born in New York City. He was the son of Robert Hoe , an English-born American mechanic who, with his brothers-in-law, Peter and Matthew Smith, established a steam-run manufactory of printing...

 in 1843, perfected in 1846, and patented in 1847. (Note – Some sources describe Parisian 'Hippolyte Auguste Marinoni', (1823, 7 January 1904) as the inventor of the Rotary printing press.)

Today, there are three main types of rotary presses; offset
Offset printing
Offset printing is a commonly used printing technique in which the inked image is transferred from a plate to a rubber blanket, then to the printing surface...

 commonly known as web offset, rotogravure
Rotogravure is a type of intaglio printing process; that is, it involves engraving the image onto an image carrier...

, and flexo (short for flexography
Flexography is a form of printing process which utilizes a flexible relief plate. It is basically an updated version of letterpress that can be used for printing on almost any type of substrate including plastic, metallic films, cellophane, and paper...

). While the three types use cylinders
Cylinder (geometry)
A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...

 to print, they vary in their method.

Offset lithography
Lithography is a method for printing using a stone or a metal plate with a completely smooth surface...

 uses a chemical process in which an image is chemically applied to a plate (generally through exposure of photosensitive layers on the plate material). Lithography
Lithography is a method for printing using a stone or a metal plate with a completely smooth surface...

 is based on the fact that water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 and oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....

 do not mix, which enables the planographic process to work. In the context of a printing plate, a wettable surface (the non-image area) may also be termed hydrophilic and (the image area) a non-wettable surface hydrophobic.

Gravure is a process in which small cells or holes are etched into a copper cylinder which is filled with ink.

Flexography is a relief system in which a raised image is created on a typically polymer based plate.

In stamp collecting
Stamp collecting
Stamp collecting is the collecting of postage stamps and related objects. It is one of the world's most popular hobbies, with the number of collectors in the United States alone estimated to be over 20 million.- Collecting :...

, rotary-press-printed stamps are sometimes a different size than stamps printed with a flat plate. This happens because the stamp images are further apart on a rotary press, which makes the individual stamps larger (typically 1/2 mm to 1 mm).
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