Types of Laser Printer

Laser printers fall into several categories, these are primarily determined by the size and throughput of the printers. This chapter describes the characteristics of each of the main categories of laser printer; Personal, Office, Workgroup, Production and Colour.


Personal laser printers are very small. They are designed to fit comfortably on a desk with other computer equipment, and are intended to be connected to a single computer for use by one user. They may also be connected to a terminal of a multi-user computer for personal use by the user of the terminal. All personal printers are simplex, as the duplexing mechanism would make them too large.

As single-user printers, most personal printers are not very fast, and typically produce around 4 p.p.m.. Personal printers hold a relatively small amount of paper, typically around 100 sheets, and often have a simple adjustable paper tray which can be used either as the main paper tray, or as a manual feed facility. Most personal laser printers can be expanded with a second paper feeder mechanism which bolts on underneath the printer, for users who print long documents or use several types of paper.

Most personal printers are supplied with a Centronics parallel communications port as standard, for connection to a personal computer. Some models are also equipped with a serial port, on others this is an optional extra. Personal printers designed for use with the Apple Macintosh computer include an Appletalk communications port instead of the parallel port, and general purpose printers which can be used with Macintosh computers can be equipped with an Appletalk port as an optional extra.

Some personal printers provide a cartridge socket for the insertion of an optional ROM cartridge containing additional fonts or another printer language emulation, however the provision of such a socket is becoming less common as manufacturers look for ways of reducing the cost of these printers.


Office laser printers are physically larger than personal printers, but still small enough to fit comfortably on a desk with a computer. They may be used by a single person, or shared by a small group of users. There are a large number of accessories available for most office printers, allowing them to be used in a wide range of applications.

Office printers generally fall in the speed range of 8 - 12 p.p.m., which is just fast enough to justify sharing them between a small group of occasional users. Alternatively they may be used by an individual user who performs a lot of printing. Office printers normally have a single paper feeder with a fixed size paper input tray holding around 250 sheets, and the option of a second paper feeder which attaches to the bottom of the printer. A few models of office printer have two feeders as standard, and almost all office printers have a separate manual feed facility which can be used without emptying the main paper tray.

Office printers normally provide both a Centronics parallel and a serial port as standard, and are usually capable of running both ports concurrently, allowing at least two computers to be attached. Most office printers also provide an expansion slot which may be used to add a multi-user communications card, supporting another four users, or a network interface card allowing connection of the printer to a network of personal computers. On a few models of office printer the expansion slot may be used with a special card for mainframe or minicomputer communications, typically using the IBM Co-Ax or Twin-Ax interfaces used on IBM mainframes and minicomputers. Some office printers are available with Appletalk or Ethertalk interfaces for connection to Apple Macintosh computers.

The wide range of communications options for office printers means that they can be used in a number of configurations. An office printer may be connected directly to several personal computers, or shared by several computers connected to a network. It may be primarily used by one individual through the parallel port, and occasionally used by several others. In some cases an office printer may be connected to both a local personal computer and to a mainframe at some remote location, eliminating the requirement of a dedicated printer for each computer.

The majority of office printers provide one or two ROM cartridge expansion slots for the addition of fonts and extra printer language emulations.

Office printers are normally simplex, but a few models of office printer have duplexing mechanisms available as optional extras. These normally bolt on to the back of the printer, and significantly increase the desk area needed. In general the add-on duplexing mechanisms are intended for occasional use, and are not reliable or robust enough for significant amounts of duplex printing. A very few office printers also have a multiple output tray system as an optional extra. This type of device is rare, and allows printed output to be directed to a specific tray for ease of sorting and separation of different users' printouts.


Workgroup printers are explicitly designed for sharing between a number of users on a network. The majority of workgroup printers are designed to be floor-standing, although a few are small enough to place on a desk or pedestal. As shared devices, workgroup printers are designed to run unsupervised, tucked away in the corner of an office or out in a corridor, rather than close to a user, and as such should be able to run without operator intervention for long periods.

As multi-user devices workgroup printers are required to print relatively quickly, and typically print at around 15 - 30 p.p.m. They may offer a few large paper trays or a number of smaller trays, but either way will hold a large amount of paper, typically around 1,500 to 2,500 sheets. A few of the smaller workgroup printers are enlarged office printers and provide a manual feed facility, but most workgroup printers don't offer manual feed as it would interrupt other users' printing activities.

Workgroup printers normally provide both a Centronics parallel port and a serial port. While they provide normal parallel and serial ports, the majority of workgroup printers are intended to be used with computer networks comprising several personal computers or minicomputers, or a combination of both. For this purpose they provide a high speed expansion slot for a network interface card. The network card usually has to be bought separately as there are many different types of network connection and network communications protocols, and most workgroup printer suppliers offer a range of network cards. As a relatively fast type of printer the workgroup printer is also suitable for use with minicomputers as a dedicated printer, so some models offer a selection of dedicated minicomputer interface cards, and a few printers also offer the Dataproducts parallel port used by some minicomputers.

A few of the smaller workgroup printers allow the use of ROM cartridges for extra fonts, however the majority of printers in this class use a built-in hard disk instead. The hard disk allows a wide selection of fonts to be loaded on to the printer to cater for the diverse requirements of a large number of users. As they are multi-user printers it is not appropriate for users to change the configuration of workgroup printers to cope with specific printing tasks, so a workgroup printer should provide enough storage for fonts, forms etc. to accommodate the needs of all its' users without reconfiguration.

On some workgroup printers the hard disk is used for job spooling, in which case the printer will provide a control panel or terminal with which the job queue can be controlled.

A few of the smaller workgroup printers offer a duplexing unit as an optional extra, but the majority are either simplex only, or have the duplexing mechanism built-in and are suitable for continuous duplex printing. Most workgroup printers also have a either a high capacity output tray with a job offsetting facility, or a multiple output tray system capable of collating users jobs. The provision of some form of job separation in the output tray is a key feature of most workgroup printers, as there will be times when there are several print jobs from different users waiting to be removed from the output tray. There are a few high-speed office printers being sold as workgroup printers, but these do not offer job separation and are not really suitable for unattended multi-user printing.


Production printers are specialist high speed printers which are normally expected to be attended by an operator. Most production printers are very large floor-standing devices, often requiring three-phase mains electricity supplies, and sometimes needing an air-conditioned "computer room" environment. The majority of production printers are designed to run continuously all day long, and some run most efficiently when used "round the clock" in a shift-working environment. These are the mainframe attached printers which are used for gas and electricity bills, bank and credit card statements, marketing mailshots, and other applications which require high speed, high volume printing.

Production printers for cut sheet paper generally fall in the range 50 - 135 p.p.m. Faster printers are available, but they require continuous fanfold stationery. Most production printers have a few very large paper feeders, a common configuration is 2 x 1,000 sheet feeders and 2 x 2,500 sheet feeders. For very high print volume environments there are devices which replace the paper feeders with a large roll of paper and cut the paper into sheets as it enters the printer, in this way tens of thousands of sheets can be printed without reloading. Production printers do not offer any form of manual feed, but their large size means that all bends in the paper path can have large radii, so most production printers will feed light card and other difficult materials without problems.

The standard Centronics parallel port and serial port used on smaller printers are not appropriate for production printers, as they do not allow the data to pass between computer and printer as fast as the printer can print it. Furthermore, most mainframe computers do not use conventional ports for their high speed peripherals. The most common connection mechanism for production printers is the IBM 370 Channel Interface. This is a high speed bus used in IBM mainframe computers, commonly known as a "bus and tag" connection, and there is a wide range of conversion units available to interface other mainframe manufacturers' bus systems to the IBM 370 bus and tag system. The other common connection mechanism for production printers is Ethernet.

All production printers include a large amount of disk storage for fonts, forms, and a large job spool, and most also include a full size terminal or personal computer for the operator to control the printer.

Production printers invariably include a duplex mechanism as standard, and high capacity output paper trays, often with a job offset facility. The quantity of paper produced by production printers presents a particular problem (a 90 p.p.m. printer running 15 hours can easily produce 75,000 sheets in a day), so there are a wide variety of "finishing" options available for production printers. These include automatic folding and stapling machines to make booklets, glue binding machines for edge bound documents, and envelope stuffing machines to fold and insert sheets into envelopes.


Colour laser printers are a relatively new development, until recently it had proved difficult to handle the paper accurately enough to position the four images required (cyan, magenta, yellow and black) exactly on top of each other. The colour printer works in the same way as a monochrome printer, except that it prints on the paper four times. Colour printers still use one photoreceptor, but successively transfer the colours to the paper, one at a time, to build up the image.

Most colour printers are designed as specialist workgroup products, so that they can be shared between several users who need colour. The speed of colour printers is low, typically 2 - 8 p.p.m. in colour mode, so they are normally only used for colour printing, and a separate conventional monochrome printer is used for normal printing.

There are a few colour printers which can operate in both colour and monochrome modes. These printers normally print monochrome as efficiently as a dedicated monochrome printer, slowing down to print the colour pages in a print job, and so can be used as a normal workgroup printer with the facility to produce occasional colour prints.

The majority of colour laser printers provide a Centronics parallel port and a serial port, and a range of network connectivity options befitting their status as shared devices.

The complex mechanisms of colour laser printers means that they are normally rather larger than the equivalent monochrome printer, which in turn provides space for several paper trays, but in general the slow speed of colour printers confines them to a specialist role, and the range of input and output options for them is limited.

Highlight Colour

There is a range of production printers produced by Xerox Corporation, who are the market leader in production printers, which provides "highlight colour". Highlight colour is the ability to place two colours on the page, normally black and one other. The Xerox highlight colour printers apply the two colours in one pass over the paper with no reduction in speed, using a special process which allows two different coloured toners to be applied to the photoreceptor at the same time. The range of shades which can be produced by this technique is amazingly wide, and can be visually very effective. In all other respects the Xerox highlight colour printers behave like normal production printers.