- A device that prints text or illustrations on paper. There are many
different types of printers. In terms of the technology utilized,
printers fall into the following categories:
Dot matrix: A type of impact printer that produces
characters and illustrations by striking pins against an ink ribbon
to print closely spaced dots in the appropriate shape. Dot-matrix
printers are relatively expensive and do not produce high-quality
output. However, they can print to multi-page forms (that is, carbon
copies), something laser and ink-jet printers cannot do.
Matrix Printer Manufacturers include Epson, Okidata
Dot-matrix printers vary in 3 important characteristics:
Speed: Given in characters per second (cps), the
speed can vary from about 50 to over 500 cps. Most dot-matrix printers
offer different speeds depending on the quality of print desired.
quality: Determined by the number of pins (the mechanisms
that print the dots), it can vary from 9, 18 or 24pins. The best dot-matrix
printers (24 pins) can produce near letter-quality type, although
you can still see a difference if you look closely.
Dot Matrix Printer use ribbon for ink
In addition to these characteristics, you should also consider the
noise factor. Compared to laser and ink-jet printers, dot-matrix printers
are notorious for making a lot of noise.
Ink-jet: A type of printer that works by spraying
ionized ink at a sheet of paper. Magnetized plates in the ink's path
direct the ink onto the paper in the desired shapes. Ink-jet printers
are capable of producing high quality print approaching that produced
by laser printers. A typical ink-jet printer provides a resolution
of 600 dots per inch, although some newer models offer higher resolutions.
Jet Printer Manufacturers include Canon, Epson, HP and Lexmark
Speed: Given in Pages per Minute (PPM) the
higher the PPM the more pages they can print. Most ink-jet printers
offer different speeds depending on the quality of print desired.
quality: Determined by the DPI Dot Per Inch
Example 2440 x 1220 DPI (Vertical and Horizontal DPI) The higher the
DPI the better in terms of print quality.
Ink-Jet Printers use Ink Cartridges (hidden cost)
general, the price of ink-jet printers is lower than that of laser
printers. However, they are also considerably slower. Another drawback
of ink-jet printers is that they require a special type of ink that
is apt to smudge on inexpensive copier paper.
Because ink-jet printers require smaller mechanical parts than laser
printers, they are especially popular as portable printers. In addition,
color ink-jet printers provide an inexpensive way to print full-color
Laser: A type of printer that utilizes a laser beam
to produce an image on a drum. The light of the laser alters the electrical
charge on the drum wherever it hits. The drum is then rolled through
a reservoir of toner, which is picked up by the charged portions of
the drum. Finally, the toner is transferred to the paper through a
combination of heat and pressure. This is also the way copy machines
Printer Manufacturers include HP, Lexmark, Xerox
Speed: Given in Pages per Minute (PPM) the higher
the PPM the more pages they can print. Most ink-jet printers offer
different speeds depending on the quality of print desired.
quality: Determined by the DPI Dot Per Inch Example
4880 x 2440 DPI (Vertical and Horizontal DPI)
Laser Printers use Toner Cartridges
• Toner Cartridge Components
• EP Photosensitive Drum
• Erase Lamp
• Primary Corona Wire
• Transfer Corona
• Power Supplies
• Turning Gears
• Ozone Filter
an entire page is transmitted to a drum before the toner is applied,
laser printers are sometimes called page printers. There are two other
types of page printers that fall under the category of laser printers
even though they do not use lasers at all. One uses an array of LEDs
to expose the drum, and the other uses LCD's. Once the drum is charged,
however, they both operate like a real laser printer.
One of the chief characteristics of laser printers is their resolution
-- how many dots per inch (dpi) they lay down. The available resolutions
range from 300 dpi at the low end to 1,200 dpi at the high end. By
comparison, offset printing usually prints at 1,200 or 2,400 dpi.
Some laser printers achieve higher resolutions with special techniques
known generally as resolution enhancement.
In addition to the standard monochrome laser printer, which uses a
single toner, there also exist color laser printers that use four
toners to print in full color. Color laser printers tend to be about
five to ten times as expensive as their monochrome siblings.
Laser printers produce very high-quality print and are capable of
printing an almost unlimited variety of fonts. Most laser printers
come with a basic set of fonts, called internal or resident fonts,
but you can add additional fonts in one of two ways:
Font cartridges: Laser printers have slots in which
you can insert font cartridges, ROM boards on which fonts have been
recorded. The advantage of font cartridges is that they use none of
the printer's memory.
Soft fonts: All laser printers come with a certain
amount of RAM memory, and you can usually increase the amount of memory
by adding memory boards in the printer's expansion slots. You can
then copy fonts from a disk to the printer's RAM. This is called downloading
fonts. A font that has been downloaded is often referred to as a soft
font, to distinguish it from the hard fonts available on font cartridges.
The more RAM a printer has, the more fonts that can be downloaded
at one time.
In addition to text, laser printers are very adept at printing graphics.
However, you need significant amounts of memory in the printer to
print high-resolution graphics. To print a full-page graphic at 300
dpi, for example, you need at least 1 MB (megabyte) of printer RAM.
For a 600-dpi graphic, you need at least 4 MB RAM.
Because laser printers are no impact printers, they are much quieter
than dot matrix. They are also relatively fast, although not as fast
as some dot-matrix printers. The speed of laser printers ranges from
about 4 to 20 pages of text per minute (ppm). A typical rate of 6
ppm is equivalent to about 40 characters per second (cps).
Laser printers are controlled through page description languages (PDL's).
There are two de facto standards for PDL's:
PCL: Hewlett-Packard (HP) was one of the pioneers of laser printers
and has developed a Printer Control Language (PCL)
to control output. There are several versions of PCL, so a printer
may be compatible with one but not another. In addition, many printers
that claim compatibility cannot accept HP font cartridges.
PostScript: This is the de facto standard for Apple
Macintosh printers and for all desktop publishing systems.
Most software can print using either of this PDL's. PostScript tends
to be a bit more expensive, but it has some features that PCL lacks
and it is the standard for desktop publishing. Some printers support
both PCL and PostScript.
The 6 steps laser printing process
* easy way to remember this is CLEAN CARS WILL DRIVE TO FAST
1. Cleaning – The Photosensitive drum is cleaned
before it can take on a new image
Conditioning or Charging – To make the drum
receptive to new images, it must be charged. The EP drum is given
a negative charge by the primary corona wire around -600 and -1000
Writing - A laser beam is use to write to the EP drum causing
dots on the drum to lose some of the negative charge
and become relatively positive charge
Developing - A toner is transferred from the toner
cylinder to the EP drum by attracting the area of the drum that has
Relative positive charge
Transferring - The transfer corona wire puts a highly
positive charge on the paper once the paper has a positive charge
the negatively charge toner particle leaps from the drum into the
Fusing - The compression roller and fusing roller
press and melts the toner into the paper the fuser gets very hot
Other Types of Printers
Photo Printer – Is a type of printer use for
Dye-Sublimation Printer – Is a type of printer which
employs a printing process that uses heat to transfer dye to a medium
such as a plastic card, printer paper or poster paper.
Thermal Printer- Is a type of printer that produces
a printed image by selectively heating coated thermo chromic paper,
or thermal paper as it is commonly known, when the paper passes over
the thermal print head. The coating turns black in the areas where
it is heated which then produce an image.
All-in-One Printer - A printer than can also do scanning, fax and make copies
Plotter - A large device use to print large posters and documents
Types of Printer Cables
USB – Standard USB Printer Cable speed is around
Parallel – IEEE 1284 Standard Cable speed is
around 1.5 to 2.77Mbps
1284 standard supported the following:
5 modes of operation (Compatibility, Nibble Mode, Byte Mode, EPP and
Supported a standard physical interface
Supported impedance and termination
Supported a standard method of connecting a host PC and peripheral
Serial – RS232 Standard Printer Cable speed
is around 57Kbps
Network, or commonly Ethernet, connections are commonplace on network
laser printers, though some other types of printers do employ this
type of connection. Generally, network printers are designed to be
shared using a central file/print server, though you can share them
off a workstation in a “workgroup” environment.
Parallel is the original standard for printers and
a lot of basic printers still rely on the parallel port connection.
A parallel (also called LPT port) sends and receives data simultaneously,
transmitting data in parallel. Parallel uses a DB25 connection on
the computer side and an oddly shaped 36 pin connection on the printer
called the centronics port.
USB, or Universal Serial Bus, is a very common connector
type for personal printers being sold today. USB is sold as the next
generation of standard ports for computers. USB allows mice, keyboards,
scanners, printers, most peripherals to connect to a computer. It
supports up to 12 Mbps transfer rate and is hot swappable.
Infrared is not very commonly used. An Infrared acceptor
allows your devices (laptops, PDAs, Cameras, etc) connect to the printer
and send print commands via infrared signals.
Serial allows your printer to connect to your computer via the serial
Firewire is a high speed connection commonly referred
to as IEEE1394, its “standard”. Though not specifically
mentioned in the preparation outline for the exam, you should be aware
that a printer may connect via Firewire. Firewire is a high speed
connection typically used for digital video editing or other high
6pin Firewire port
connection such as Bluetooth is also popular for connecting printers
in a network environment
An HP Jet direct (or Printer Server Box) is a device
which allows a non-networkable printer to be networked. For example,
we have an Epson color inkjet printer in our office which has a standard
parallel port connection on it. The Jet Direct box allows the printer
to be connected into our network and allows the printer to be shared
off of our file/print server.