Glossary of Terms

Fast & Slow Scan Directions

In inkjets with moving carriages, the "fast scan" is the direction of the relative movement of the head and substrate. The "slow scan" direction is at 90 degrees to the fast one. These terms are useful when relating the printing motion to a particular image. Single-pass inkjets (such as digital label presses and web fed commercial inkjets) also have different characteristics for the print width and the length (ie the direction that the media travels in), as the width resolution is constant while the length varies with the speed that the media is fed under the heads.

File server

Also called Server. Central computing resource on a network of intelligent terminals. It's used for storage of things that many users might need access to, such as picture and page files. Also used for intensive background processing tasks, such as printing or Ripping. Acts as a controller and routing system for some types of network.

Film

Clear stuff that can carry photographic images. It has largely been replaced by digital cameras for original photography, but it's still used in pre-press as an exposure mask material for screen meshes, lithographic plates and some other analogue printing plates or cylinders.

Firing frequency

The number of drops ejected from each nozzle per second in a printhead. For example, a Xaar 1001 GS6 head has a firing frequency of 7 kHz, meaning 7,000 drops per second.

Flushing

Forcing ink through the printhead nozzles at high pressure, usually in an attempt to clear a blockage. It can waste a lot of ink and is not always successful. Sometimes a special flushing fluid is used. See Purging.

Foaming

The formation of a foam of air bubbles in ink, caused by dissolved gas. This only affects low viscosity inks. Depending on where the foaming occurs, it may be a problem or an intended effect. If bubbles or foaming occur in a printhead's ink chamber, it can cause misfiring or blockages.

Folders

A class of print finishing machines that takes a sheet or roll media and fold it over on itself. Sheet fed folders can fold in two directions to create multi-page sections, that typically are used in books or brochures after the spine has been glued or stitched and one or more of the edges is trimmed off to allow the pages to open.

Fonts

A font is a collection of characters and symbols all of the same style for a particular typeface. Thus Futura Light is a font, and so is Futura Extra Bold.

Four-colour

Referring to the four-colour printing process, where cyan, yellow, magenta and black inks are used to give full-colour halftones. See colour, separation.