Glossary of Terms

The manufacturers of laser printers use a wide range of terms to try and distinguish features of their printers, so there are many terms in use which have the same meaning. Within this book "industry standard" terminology is used wherever possible, however the specification sheet for a printer may use different terms, so this glossary includes many of the common terms used by different laser printer manufacturers.

an alternative name for twisted-pair network connections
A3, A4, A5 paper
standard European paper sizes, A3 measures 297 mm x 420 mm, A4 measures 210 mm x 297 mm, and A5 measures 148 mm x 210 mm.
Adobe PostScript
a page description language (PDL) developed by Adobe Systems Incorporated, and used on many high-end printers.
Adobe Type 1 font
a font definition format for outline fonts developed by Adobe for use with PostScript. Type 1 fonts include a "hinting" mechanism which helps in the aesthetic reproduction of fonts at small sizes to overcome the restrictions imposed by low resolution printers.
Adobe Type 3 font
a font format for outline fonts developed by Adobe for use with PostScript. Type 3 fonts do not have a "hinting" mechanism and are easier to create.
Adobe Type Manager (ATM)
a font management and rasterisation program which converts Adobe Type 1 and Type 3 fonts to bitmaps for printing or display on a computer screen. ATM is available as a program to run in the Windows environment to allow the display of PostScript fonts by Windows programs, and is built-in to some other graphical user interfaces.
Average Monthly Print Volume, a method of expressing the monthly volume of usage a printer is intended for.
A network protocol used by Apple Macintosh computers, normally used in conjunction with LocalTalk, Apple's proprietary network topology.
"American Standard for Computer Information Interchange", ASCII defines a number of character set encodings (the assignment of characters to numbers for use by computers) for different latin-based languages. ASCII encoding is used on most computers other than IBM mainframe and minicomputers which have their own character set encoding, EBCDIC.
a type of connector used in standard "thick" Ethernet installations to connect devices to the network. An AUI connector is a 15-pin D-type plug.
B4 paper
a rarely used European paper size measuring 250 mm x 353 mm
a common term for a photoreceptor made as a continuous flexible belt.
an array of dots, normally containing an image formed by a pattern of "white" dots and "black" dots.
bitmap font
a font in which each character is stored as an array of dots, the pattern of which forms a letter or symbol.
bitmap graphic
an array of dots, in which the pattern of the dots forms a picture or other non-text item such as a line.
a fast bi-directional parallel communications interface developed by Hewlett-Packard, which is backwards compatible with the Centronics parallel interface.
a bayonet-style co-axial connector normally used to connect devices to thin "cheap" Ethernet networks.
Boise specification
the specification for Bi-Tronics communications ports, developed by Hewlett-Packard engineers at Boise in the USA.
built-in font
see resident font
bus and tag connection
the connection mechanism normally used to connect devices to the IBM 370 Channel interface on IBM mainframes.
cache memory
RAM which is used as a temporary holding place to allow fast access to some transient data. In printers cache memory primarily refers to the font cache, where bitmaps generated from outline fonts are held ready for use.
Computer-Aided Design, a type of computer software application used for engineering drawings, which often requires a special printer language emulating a pen plotter.
may refer to ROM cartridge, font cartridge, emulation cartridge, toner cartridge, toner/developer cartridge or print cartridge.
a parallel communications interface designed by the Centronics corporation for use with printers, and adopted as the de facto standard for parallel communications between computers and printers
channel interface
abbreviation for the IBM 370 Channel interface used by IBM mainframes for the connection of peripherals.
an individual letter, number or other symbol in a font.
character attributes
a misnomer for typestyle, commonly used to refer to bold, italic, underline and other typestyle qualifiers used with a typeface.
charged roller
a roller in a laser printer which imparts an electrostatic charge to another surface. Charged rollers are used in some small printers in place of corotrons to reduce ozone emissions.
generic term for a network topology where the network has two type of computer attached, those which access the network (clients) and those which provide facilities to network users (servers).
Cyan, Magenta, Yellow, Black. A colour encoding method frequently used on colour printers, where a colour other than black is defined by the proportions of cyan, magenta and yellow required to reproduce the colour. Black is provided separately to ensure ultimate "blackness".
communication port
an alternate term for a communication interface
communication interface
a communication interface is a mechanism through which data may transmitted or received by a computer, printer or other computing device. Communications interfaces normally fall into three categories, serial, parallel and network interfaces.
any replaceable component of a laser printer, such as the toner, photoreceptor etc.
contour font
an alternative term for an outline font.
control panel
the panel on the front of a printer which allows the user to configure the printer by selecting which emulation is used, which communications port to use etc. The control panel normally includes a status display which shows configuration menu options and printer operation status messages to the user.
normally an abbreviation of printer controller, the dedicated computer in a printer which creates the image to be printed.
a wire in the printer mechanism which carries a very high voltage to generate an electrostatic charge on a nearby surface, such as a photoreceptor or sheet of paper. There are several corotrons in most printers. The high voltage in corotrons ionises the air surrounding the corotron and generates ozone gas as a by-product.
normally refers to the amount of the paper which is covered with toner. A typical page of text will have a coverage of 4 - 5%.
Customer Replaceable Unit, an alternative term for a consumable.
a parallel communications interface designed by the Dataproducts corporation for use with printers, and used by some minicomputers for parallel connection to printers.
the mechanism and magnetic powder used to transfer toner from the toner hopper onto the photoreceptor.
a single point written by a laser, or a single point in a bitmap.
to transfer data from a computer to a printer
downloaded font
a font which is stored in a computer, and sent to the printer via the communications interface when required, to be stored in the printer. Normally downloaded fonts are held in RAM on the printer, and are lost when the printer is switched off. Some printers are able to hold downloaded fonts on hard disk to prevent loss when the printer is switched off.
a common term for a cylindrical photoreceptor.
desk-top publishing, a class of computer application used for the production of newsletters, magazines, manuals and other complex documents. The complexity of documents produced using DTP packages means that they are normally used with PDL printers.
double-sided, a sheet of paper on which both sides are printed.
"Extended Binary-Coded Decimal Interchange Code", EBCDIC defines the character set encoding (the assignment of characters to numbers for use in computers) used by most IBM mainframes and minicomputers. The majority of non-IBM computers and personal computers use ASCII.
edge enhancement
a generic term for the edge-smoothing technique which reduced the jagged appearance of angled lines on laser printers, as used in HP's Resolution Enhancement Technology, and copied by many other printer manufacturers.
a generic term for a printer language. Most printers mimic or "emulate" the behaviour of the market-leading models of printer by copying their printer language.
normally an abbreviation of printer engine, the mechanism which "writes" a bitmap onto paper.
Erasable Programmable Read Only Memory, a type of memory chip which normally holds information permanently, but which can be wiped clean and reprogrammed under specific conditions, normally using ultra-violet light.
escape code
a special control character used by computers and printers, character number 27 decimal, 1B hexa-decimal in the standard ASCII character set.
escape code language
A printer language in which each command is preceded by a special character, normally the escape code, to signify that what follows is a command rather than data.
escape sequence
a sequence of characters which form a command to be obeyed by the printer, preceded by the escape code and ended with a termination character.
the most popular physical connection mechanism for connecting groups of computers together in a network. Ethernet can be used to form client/server or peer-to-peer networks.
eurolegal paper
a European paper size measuring 8½" x 13". Eurolegal is supported by relatively few laser printer manufacturers.
refers to an output tray on a printer in which pages are delivered with the readable side upwards. As each sheet is placed on top of the last, multi-page documents delivered to a face-up tray are normally in reverse page order.
refers to an output tray on a printer in which pages are delivered with the readable side facing down. As each sheet is placed on top of the last, multi-page documents delivered to a face-down tray are normally in the correct page order.
FAX modem
a specific type of modem used for sending and receiving facsimiles. Used by some manufacturers to refer to a facsimile option on a laser printer, as a facsimile option must include a FAX modem.
software which is stored in ROM. In printers the firmware is normally the software permanently stored in the printer controller.
first print out time
the time taken between a printer receiving the data for the first page of a print job, and delivering the page to the output tray. Most printers do not start printing immediately the data is received, but need a few seconds in which to assimilate the data, setup the page formatting, and start the motors which drive the paper path.
flash memory
a type of EPROM which can be wiped clean and reprogrammed electronically, and thus may be used for semi-permanent storage of downloaded fonts as an alternative to a hard disk.
a collection of characters in a particular typeface, typestyle, and character set. A bitmap font is normally also defined by size and orientation.
font cache
an area of RAM in a printer which is used for the temporary storage of bitmap fonts which have either been read from hard disk, or created from outline fonts.
font cartridge
a ROM cartridge containing either bitmap or outline printer fonts.
the mechanism in a laser printer which binds the toner to the paper. Most fusers use hot rollers and fuse the toner into the paper using heat and pressure, but a few printers have radiant fusers which fuse using heat alone.
fuser oil
a temperature resistant oil used on fuser rollers to prevent toner adhering to the surface of the rollers. On small printers the fuser oil is normally contained in the fuser cleaning pad.
Graphical Device Interface, a term normally used to refer to the software mechanism used by Microsoft Windows software to exchange information which is to be displayed or printed between the Windows environment and Windows applications.
grey scale
a technique where shades of grey are synthesised using patterns of black and white dots.
grammes per square metre, the standard European measurement of paper weight.
hard disk
an electromechanical mechanism used in computers and some printers for the semi-permanent storage of data including fonts.
host computer
any computer to which the printer being discussed it attached, but commonly used to refer to mainframe computers.
Hewlett-Packard Graphics Language, a vector graphics language used by Hewlett-Packard plotters and commonly output by CAD software. Some laser printers emulate HPGL to allow their use with CAD packages.
Hewlett-Packard Interface Bus, a parallel communications mechanism used primarily for the connection of scientific and engineering instruments and computers, but also provided on a few printers.
Hewlett-Packard Printer Control Language. The most popular and widely emulated Escape Code printer language. PCL is available in several variants including PCL 3 , 4 and 5, each of which provides more facilities than the previous variant.
input tray
an alternative term for a paper tray
a font definition format for outline fonts developed by Compugraphic for use with laser printers. Intellifont outline fonts are used by HP PCL 5 printers and many PCL 5 emulations.
images per minute or impressions per minute, a measure of the speed of a laser printer, where each sheet of paper has more than one image as in duplex printing.
job separator
a sheet produced by some workgroup printers before each print job to identify the user to whom the job belongs.
a Local Area Network is a method of interconnecting groups of computers, allowing them to share resources such as disk storage and printers.
refers to the orientation of a page. A page is said to have landscape orientation when the text is read parallel to the long edge of the paper.
an acronym for "Light Amplification by the Stimulated Emission of Radiation", a laser beam is characterised by comprising light waves which are phase synchronised and parallel to obtain maximum intensity.
an abbreviation for Light Emitting Diode, a solid-state electronic component which emits light.
ledger paper
a North American paper size, measuring 11" x 17".
legal paper
a North American paper size, measuring 8½" x 14".
letter paper
a North American paper size, measuring 8½" x 11".
the physical wiring and connection mechanism used in AppleTalk networks.
a graphic device, such as a company logo or special symbol, which can be stored as a character in a special font for use with laser printers.
anything which a laser printer can print on, e.g. paper, card, transparencies and labels.
modulator-demodulator, a device which converts serial communications data into audible tones for transmission over telephone links.
data storage space, typically RAM. The larger the amount of memory in a printer, the more data the printer can hold, and hence (generally) the more complex the pages it can produce.
normally refers to a Local Area Network (LAN), although there are also Wide Area Networks, and public telecommunications systems are often referred to as networks in the context of interconnecting computers.
network interface
an interface which allows a printer to be connected directly to a LAN, normally in the form of a card which plugs into the printer controller, but also available as an external box called a print server.
network printer
a printer which is designed to connect to a network and be used by groups of users, a sub-class of workgroup printers.
network protocol
the software data transfer mechanisms which pass data between computers and between computers and printers, on a LAN.
network topology
the manner and design in which computers are connected to a network, the topology describes both the physical connection mechanism, such as Ethernet, and the network type, such as client/server.
office printer
a printer which is designed for general purpose office use, and may be used by an individual user, or shared by a small group of users.
offset mechanism
a mechanism in the output part of some workgroup and production printers which pushes alternate jobs sideways in the output stack thereby separating one job from another.
organic photoconductor (OPC)
a type of photoreceptor material commonly used for photoreceptor belts and also used on the photoreceptor drums of some smaller printers.
outline font
a font in which each character is represented by sets of equations or vectors which define the outline of the character. An outline font cannot be printed "as is", but must first be scaled to the appropriate size, and "filled" with dots to make a bitmap. As outline fonts can be scaled they may be used to create characters of any size, and may be rotated to any angle.
output tray
a shelf or tray on the outside of the printer which receives and collects the printed pages.
a unstable corrosive gas (O³) produced by the ionisation of air which occurs around corotron wires.
ozone filter
a carbon filter, normally a mesh, which ozone gas oxidises, thus reducing the ozone to oxygen.
paper feeder
the part of a printer which feeds sheets of paper from a stack into the printing mechanism. Normally the paper feeder feeds from a paper tray, but some designs of paper feeder do not use a tray.
paper path
the path which the paper describes as it moves through the printer from the paper feeder to the output tray.
paper tray
normally a cassette which holds a particular size of paper and inserts into the paper feeder, however some cassettes are adjustable for several sizes of paper, and some paper feeders provide adjustable paper guides eliminating the need for a paper tray.
parallel interface
a communication mechanism used to transfer data from a computer to a printer, several bits at a time. Most parallel interfaces are 8 bits wide, and thus transfer one byte in each transaction, however a few are 16 bits wide, transferring two bytes simultaneously.
a Personal Computer, normally meaning an IBM-compatible personal computer, but equally valid in describing other personal computers such as the Apple Macintosh.
Printer Command Language, normally in reference to Hewlett-Packard Printer Command Language (HP PCL), but most manufacturers emulating HP PCL leave out the HP.
Page Description Language. A programming language used to describe a page for display or printing in terms of the text and graphics on a page, and effects which may be applied to them.
a network topology in which all computers on the network are able to access each others resources, as opposed to client/server networks where clients access common resources provided by servers.
personal printer
a small laser printer, typically producing 4 - 5 p.p.m, which is physically compact to allow easy use on a desk, and sufficiently inexpensive to justify ownership by an individual for their personal printing needs.
the component in a laser printer which is light sensitive, and in which on exposure to light the surface electrostatic charge changes, enabling a pattern of electrostatic charge to be created with a laser. The pattern of electrostatic charge is then used to attract toner and transfer it to a sheet of paper.
a "picture cell element", commonly used as a misnomer for a dot in laser printing. It is a misnomer because a laser printer dot is an indivisible unit, whereas a pixel may actually comprise several dots arranged in a matrix to form a shade of grey.
an abbreviation of communications port, an alternate term for a communications interface.
refers to the orientation of a page. A page is said to have portrait orientation when the text is read parallel to the short edge of the paper.
an abbreviation of pages per minute, the standard measure of throughput or speed for laser printers. p.p.m is an adequate measure for simplex printers, but duplex printers are more appropriately measure in images per minute (i.p.m)
print cartridge
a print cartridge is a printer consumable which normally contains all the major replaceable elements in a laser printer, such as toner, developer and photoreceptor.
print drum
a common term for a cylindrical photoreceptor.
print engine
the mechanism which transcribes a bitmap created by the printer controller into a printed image.
print job
any group of pages which are to be printed together.
print server
a device used to connect a stand-alone printer to a LAN.
printer controller
the dedicated computer in a printer which receives data to be printed from a computer, along with commands defining how the data should be formatted, and uses these to create (rasterise) a bitmap describing the image required on the paper which is then passed to the print engine for transcription to the paper.
printer driver
a software utility incorporated into a software application package on a computer which enables the application to determine the commands required by the printer to format data for printing, and which provides the application with information about the facilities provided by the printer.
printer font
any font which is designed for use on a printer.
production printer
a large heavy-duty printer designed for almost continuous printing in a production environment, either for large quantities of small documents such as invoices and account statements, or for small quantities of large documents such as reports, short-run books, newsletters etc.
the process of converting data and command received from a computer into a bitmap containing an image to be printed.
resident font
any font which is built-in to a printer by the manufacturer as one of the standard features offered by the printer.
the number of individual dots a printer can print in a given area, normally expressed as dots per inch (d.p.i).
RAM (random access memory)
a type of temporary storage space used in computers and printers which is created using integrated circuits and which may be written into and read from by the computer as required. RAM only preserves its contents while power is present, so the contents of RAM are lost when the power is switched off.
Red, Green, Blue. a colour encoding method normally used on computer displays in which each colour to be displayed is described in the proportions of Red Green and Blue required to make the colour.
a connector commonly used with twisted-pair networks, an RJ45 plug is very similar to a telephone plug.
ROM (read-only memory)
a type of permanent storage space used in computers and printers which is created using integrated circuits, and which may be read from by the computer, but may not be written to. ROM preserves its contents indefinitely, so the contents remain even when power is removed.
ROM cartridge
a small case containing a printed circuit board on which several ROM chips are mounted, and which can be inserted into a special slot in a printer. The ROM chips are normally used to hold fonts or printer language emulations.
a common serial communications method used by most computers.
a serial communications method which offers higher performance than RS232C, but is less commonly used.
scaleable font
a font which can be scaled to any size, used as an alternative term for an outline font.
screen font
a font which is designed for display on a computer screen.
serial interface
a communication mechanism used to transfer data from a computer to a printer, one bit at a time. Serial communication is much slower than parallel communication, but may be used to transfer data over long distances and requires fewer wires.
single-sided printing, where one side of a sheet of paper is printed on, and the other side is not.
sixel graphics
a method of encoding bitmap graphics so that they may be reliably transmitted using serial communication links.
soft font
an alternative term for a downloaded font.
software driver
a generic term for a software utility such as a printer driver.
commonly used to describe the throughput of a laser printer measured in p.p.m or i.p.m.
"spots per inch", used by some manufacturers as an alternate term for "dots per inch".
a paper output tray, normally a high capacity output tray that incorporates a motorised elevator which lowers the height of the output paper stack to allow more paper to be added to the top of the stack.
status message
a message displayed on the control panel of a printer to indicate the status of the printer, or indicate an error condition or the need to replace a consumable.
status sheet
a page generated by a printer controller to indicate the status of a printer, including information about the configuration of the printer.
the productivity of a printer in terms of pages printed in a given time, normally measured as pages per minute (p.p.m).
Token Ring
a network topology often used in conjunction with IBM minicomputers.
a fine coloured plastic powder which is used to form an image on a sheet of paper.
toner cartridge
a cartridge or cassette which holds toner for ease of loading into a printer.
toner/developer cartridge
a cartridge containing both toner and developer for loading into a printer, usually including the developer roller and the associated drive gears which rotate the roller, and the toner hopper which is formed by the cartridge casing.
a font definition format for outline fonts which is used by Microsoft Windows for the creation of screen fonts and downloaded fonts.
twisted pair
a low-cost connection method for creating Local Area Networks, often used to distribute connections from a multiple connection point (a "hub") on an Ethernet network.
Type 1 font
an abbreviation of Adobe Type 1 font, generally used by other font suppliers when supplying fonts in Adobe Type 1 format.
Type 3 font
an abbreviation of Adobe Type 3 font, generally used by other font suppliers when supplying fonts in Adobe Type 3 format.
a the visual design of a set of characters or a font.
a modifier used to vary the appearance of a typeface without changing its basic shape, such as bold or italic.
UI (user interface)
any part of a device which is used for communication between the device and the user or vice versa, on a printer the user interface is the control panel.
vector graphics
a method of describing lines and curves as mathematical equations or vectors.
warm-up time
the time taken after switching for a printer to achieve a state where it is ready to print. The warm-up time is normally dictated by the time taken to heat up the fuser to its operating temperature
winchester disk
a particular type of hard disk using technology developed by IBM laboratories in Winchester.
workgroup printer
a medium-sized laser printer designed to handle the printing requirements of several users, normally attached to a LAN or multi-user computer.