3. Introduction
Printers are classified into Impact and non impact printers.
LASER stands for Light Amplification by Stimulated Emission
of Radiation.
Laser printers uses electrostatic printing process.
Laser printers are used to produce high quality images and
graphics.
It is a type of printer that
utilizes a laser beam to produce
an image on drum.
It uses a non-impact (keys
don't strike the paper),
photocopier technology.
4. History
Laser printer invented by Gray Starkweather at in
1969 when American Xerox Corporation held a
dominant position in the copier market In 1960.
Commercially IBM introduced the first laser printer in
1975 to use it with its mainframe computers.
In 1984, Hewlett-Packard ( HP )
revolutionized laser-printing
technology with its first
LaserJet, a compact, fast, and
reliable printer that personal
computer users could afford.
Gray Starkweather
5. Basic Components
• The drum inside the toner cartridge is photosensitive,(reacts to light)
• The laser beam is reflected onto the surface of the drum to create a pattern of charged representing the image of the
page to be printed.
Drum
• The laser beam paints the image of the printed page on the drum.Laser
• The process uses very high voltage to charge the drum and transfer and hold the toner on
the paper.
Power supply
• The paper path for laser printers ranges from a simple, straight path to the complicated turns of devices
• The goal is the same for all these devices-to move the paper from a supply bin to the engine where the image is laid on the paper and
fixed to it
Paper
transport
• The primary corona charges the photosensitive particles on the surface of the drum.
Primary
cornea
• The transfer corona charges the surface of the paper just before it reaches the toner area.Transfer corm
• The fuser makes the printed pages hot.
• The toner is melted permanently to the page by apply pressure and heat (between 165 and 180C) to it.Fusing Roller
• It communicates with the OS of printer, and forms the image printed on the page.
• This is the motherboard of the laser printer, and it has architecture and components like a PC motherboard.
Controller
6. Laser Printing Process
Cleaning: Before a new page is printed, any remaining
from the previous page are cleared away. The drum is
swept free with a rubber blade,
and a fluorescent lamp
removes any electrical charge
remaining on the drum.
Conditioning: The entire
drum is uniformly charged by
the primary corona wire. This
charge conditions the drum
for the next step.
7. Writing: The laser printer controller uses a laser beam and a
series of mirrors to create the image of the page on the
drum. The laser beam is turned on and off in accordance
with the image to be created on the drum.
Developing: A magnet inside the developing roller attracts
the iron particles in the toner. This roller rotates near the
drum and the toner is attracted to the areas of the drum that
have been exposed by the laser, creating the print image on
the drum.
(Toner : the electrostatic image
is created by changing the
charges on different places.
The drum continues to revolve
and the toner sticks to the
negatively charged places of
the text.)
8. • Transferring: A magnet inside the developing roller
attracts the iron particles in the toner. This roller
rotates near the drum and the toner is attracted to the
areas of the drum that have been exposed by the laser,
creating the print image on the drum.
• Fusing: The fusing rollers apply
heat and pressure to the toner,
which melts and presses it into
the paper to create a permanent
bond. The rollers are covered
with Teflon and treated with a
light silicon oil to keep the paper
from sticking to them.
9. Advantages
It is a very fast printer.
The printing cost of laser printer is less than inkjet
printer.
It has the ability to print the high resolution
images that is 1200 dpi consuming less time.
It makes no noise during
printing process.
Their maintenance time span
is longer (changing of the
toner)
Its efficiency is very high.
10. Disadvantages
It is very expensive.
The maintenance cost is high.
Very Bulky and difficult to repair.
It has health hazards.(gases like ozone, nitrogen
oxide, carbon monoxide are emitted which are
harmful for health.)
Also emit Ultraviolet radiation that can cause eye
damage.
11. Applications
For taking huge printout.
For hoardings and banner printings.
For taking light fast printouts.
For printing books, newspapers etc in huge
industries.
12. Latest Laser
printers (2016)
40 Pages per minute.
Maximum storage memory 512 MB.
Toner capacity of printing 5000 pages.
Capacity of printing 2400 dpi .
Wireless printing.
Photo printing.
32 Pages per minute.
Maximum storage memory 128 MB.
Toner capacity of printing 4200
pages.
Capacity of printing 2400 dpi .
Wireless printing.
XEROX COLORQUBE 8570DN
BROTHER HL-L8350CDW
Photosensitive Drum
The photosensitive drum is a key component and usually is a part of the toner cartridge. The drum is an aluminum cylinder that is coated with a photosensitive compound and electrically charged. It captures the image to be printed on the page and also attracts the toner which is to be placed on the page.
High-voltage power supply
The process uses very high voltage to charge the drum and transfer and hold the toner on the paper. The high-voltage power supply converts AC current into the higher voltages used by the printer.
Paper transport
Inside the laser printer are four types of rollers that move the paper through the printer. Each rubberised roller or set of rollers is driven by its own motor. The four roller types in the paper transport system are the feed, registration, fuser and exit roller. This is where most paper jams in a laser printer occur.
Primary Corona
Also called the main corona, this device forms an electrical field that uniformly charges the photosensitive drum to +600V to reset it prior to receiving the print image and toner.
Transfer Corona
This mechanism moves a page image from the drum to the paper. The transfer corona charges the paper; the charge pulls the toner from the drum onto the paper. As the paper exits the transfer corona, a static charge eliminator strip reduces the charge on the paper so that it won't stick to the drum.
Fusing Rollers
The toner is melted permanently to the page by the fusing rollers that apply pressure and heat (between 165 and 180C) to it. The fuser - not the laser - makes the printed pages hot.
Controller
This is the motherboard of the laser printer, and it has architecture and components like a PC motherboard. The controller communicates with the PC, houses the memory in the printer, and forms the image printed on the page. Memory expansion is possible on virtually all laser printers. Adding memory allows the printer to reproduce larger documents or graphics in higher resolutions or to support additional soft fonts.
Writing
The laser printer controller uses a laser beam and a series of mirrors to create the image of the page on the drum. The laser beam is turned on and off in accordance with the image to be created on the drum. At the spot where the laser's light contacts the photosensitive drum, the charge is reduced. After the entire image has been transferred to the drum, the controller starts the page sheet through the printer, stopping it at the registration rollers.