Book folding
Encyclopedia
Book folding is the stage of the book
Book
A book is a set or collection of written, printed, illustrated, or blank sheets, made of hot lava, paper, parchment, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf or leaflet, and each side of a leaf is called a page...

 production process in which the page
Page (paper)
A page is one side of a leaf of paper. It can be used as a measurement of documenting or recording quantity .-The page in typography:...

s of the book are folded after printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....

 and before binding
Bookbinding
Bookbinding is the process of physically assembling a book from a number of folded or unfolded sheets of paper or other material. It usually involves attaching covers to the resulting text-block.-Origins of the book:...

.

Until the middle 19th century, book folding was done by hand, and book folder was a trade. In the 1880s and 1890s, book folding machines by Brown and Dexter came onto the market, and by the 1910s hand-folding of sheets was rare, with one publisher declaring them, in 1914, to be "practically obsolete".

The process Folding is also necessary to produce print products except for books for instance mailings, magazines, leaflets etc.

Folding machines

Two main types of mechanisms are commonly employed in folding machine
Folding machine
A folding machine is a machine used for folding, usually of paper.A fold can be made by a Buckle or a Knife.There are generally three types of folding machines. Buckle Folders, Knife Folders or a Combination of these two types....

s: buckle folders and knife folders.

Buckle folder

In a buckle folder, the paper is first passed through 2 spinning rollers, which feed the paper into a pair of guide plates that redirect the paper at a slight angle, bending the paper. At the far end of the guide plates is a "paper stop". As the rollers continue to spin, the paper continues to slide in between the guides until it hits the paper stop, then, having nowhere else to go, buckles at the interface between the rollers and the angled guides. As the rollers continue to spin, the buckle increases, until it is eventually caught by a pair of "nip" rollers, which pull the buckle in and compresses and flattens it into a neat crease.

Adjusting the paper stop in a buckle folder determines where the fold will be placed. Also, a buckle folder may contain only 3 rollers, with one shared by both the input rollers and the nip rollers.

Although buckle folders are fast, simple, efficient, and have small folding tolerances, they are not suitable for substrate of very low (<40g/m²) or very heavy paper grammage (>120g/m²).

Knife folder

In a knife folder, a sheet of paper is fed horizontally over 2 unpowered rollers until it hits a paper stop, at which point a dull blade pushes down on the paper and in between the 2 rollers to create the fold.

Although the knife folder is slower than buckle folders, it is more precise and can handle extreme grammages very well. It also has small folding tolerances, but is a more complex machine.

Folding Variants

Parallel folds

Folding a paper more than once in the same direction (i.e. with parallel creases) is called parallel folding. Common examples of this are the half fold, letter fold, gate fold, and Z-fold.

Cross folds

A cross fold is when a paper is folded once, then rotated 90 degrees and folded again. The creases therefore cross each other at right angles. The most basic cross fold is the French fold, or right-angle fold. Other examples include the 16-page broadside and the 12-page letter.

See also

  • Book
    Book
    A book is a set or collection of written, printed, illustrated, or blank sheets, made of hot lava, paper, parchment, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf or leaflet, and each side of a leaf is called a page...

  • Book publishing
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