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-1938Charles Carlson invented the Xerography (dry printing
proccess)
1939-1942applied for patent
1947sold rights to Haloid Company (xerox)
1967: idea of a laser printer was bornGary K. Starkweather (B.S.
in Physics from Michigan State University in 1960, and a M.S. in
Optics from the University of Rochester in 1966-thought hat if,
instead of copying someone else's original, which is what a
facsimile does, we used a computer to generate the original?thus
started the research of laser printers
after a while, Xerox did not support the research work of
Staekweather so he did it on his own
1969first prototype by Starkweather
built by modifying an existing xerographic copier.Starkweather
disabled the imaging system and created a spinning drum with 8
mirr
ored sides,with a laser focused on the drum. Light from the
laser would bounce off the spinning drum,sweeping across the page
as it traveled through the copier.The hardware was completed in
just a week or two, but the computer interface and software took
almost 3 months to complete.
1970Xerox build the Palo Alto Research Center (PARC) in
California.Starkweather was asked to work there
1971First working laser printer was built
called SLOT or Scanned Laser Output Terminal.
1972the digital control system and character generator for the
printer were developed by Butler Lampson and Ronald Rider .
months later, the printer was named EARS(Ethernet, Alto,
Research character generator, Scanned laser output terminal).The
EARS printer was used with the Alto computer system network and
subsequently becamethe Xerox 9700 laser printing system.
1979
IBM introduces the IBM 3800 laser printer, capable of printing
20,000 lines perminute.
1984Hewlett-Packard introduces the LaserJet laser printer,
featuring 300dpi resolution, for US$3,600.
1985Apple Computer releases the Apple LaserWriter laser
printer.
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90 s many people owned this printers at home and in offices
2000 onwards development
becaome more eco-friendly and affordablecan be connected to the
internet for wireless printing
A drum assembly inside the printer receives a positive
electrical charge from awire with a current running through it.A
laser then traces onto the drum the image to be printed, creating a
negatively charged electrostatic image.Next, the drum gets coated
in positively charged toner, which clings to the negatively charged
image but nothing else.The paper is given its own negative charge
that's stronger than the electrostatic image on the drum so it can
pull the toner away from it.The drum rolls over the paper,
transferring the image to the paper.The paper's electrical charge
is discharged.The toner is fused to the paper.
STEPs
1. contorller- translates data thourgh Raster Image Proccessor
or RIP, convertin
g the image into tiny dots2. Image drumming- is a coated
cylinder that recieves positive electrical charge from a wire with
a current running through it.3. changing roler- sends positive or
negative charge to imaging drum4. laser beam- switches on and off
intermittenly as it traces onto the drum theimage to be printed,
creating a negatively charged electrostatic image5. Rotating mirros
- deflects laser beam onto the drum scanning the charged drum
reversing the charge inorder for the dots/image to cling that are
to be printed6. develper roller- coated in charged toner particles
from toner catridge7. Toner hopper- part of the toner cartridge,
feeds toner particles into developer roller8. Transfer belt or
roller- assembly draws paper inside from the paper tray
9. transfer rollder- applies a charge opposite to the toner's
paper for it o become stronger than the electrostatic image on the
drum so it can pull the toner away from it then the paper's
electical charge gets discharged10.the paper's electical charge
gets discharged11. cleaning blade- cleans drum so that when the
printer will be used again, itcan generate a new image.
12. fuser- heat roller and pressure roller that melts the toner
onto the page
finish!! :)
