Printers Flashcards
What are the seven different types of printers?
Band/chain printer Dot matrix printer Laser printer Inkjet printer Plotter printer Dye sublimation printer Thermal printer
Describe the Band Chain printer
Uses a chain made up of stamps of each of the letters of the alphabet, numbers and punctuation marks
Chain moves past the paper; as a letter on the chain moves past where it should appear on the paper it is stamped onto the paper
Describe the charateristics of the Dot matrix printer
Print head moves horizontally across paper line by line and characters (and graphics) are created as a 2-D array/matrix of dots Noisy while printing - some have a lid or covering unit to help block out the noise Side of paper has holes that are aligned in the dot matrix printer Limited settings (i.e. font types, font sizes, paper sizes) Replaced by inkjet and laser printers
Describe the operation of the Dot Matrix printer.
PC sends printer a series of hexadecimal ASCII codes, which represent characters, punctuation marks, and printer movements (i.e. tabs, carriage returns, line feeds, and form feeds)
ASCII codes are stored in a buffer area, part of the printers RAM
Among other codes are commands that tell the printer to use a certain font’s bitmap table - this information is stored on read-only memory chips found on the printers circuit board
Printers processor takes the required information for an entire line of type, calculating the most efficient path for the print head to travel
Print head contains one or two vertical columns of 9 or 24 printing pins
One end of each of the pins is matched to an individual solenoid, or electromagnet
Electrical signals from the printers processor activates the solenoid, which creates a magnetic field that repels a magnet on the end of the pin, causing the pin to strike the paper through a black inked ribbon
The printers processor also controls the movements of the print head and platen
Describe the characteristics of the Laser Printer
Technology developed from photocopiers
Usually uses black toner (electro statically sensitive, dyed powder)
Colour laser printers will become more popular because they are coming down in price
Heat from the fusing system is what causes paper fresh from a laser printer to be warm
Describe the operation of the laser printer
PC’s OS and software send one of two types of signals to the laser printers processor to determine where the toner will be placed on the paper
an ASCII code
a page description language command
Instructions from the printers processor modulate (on/off) a beam of light from a laser
A spinning polygon mirror deflects the laser beam so that the path of the beam is a horizontal line across the surface of the OPC drum (Organic Photoconductor Cartridge)
OPC drum is a drum with a fluorescent photosensitive organic coating, and is uniformly charged to 1000 volts
OPC drum is usually referred to simply as the drum
Laser beam discharges the OPC drum surface where it strikes, leaving a pattern of charged and discharged points on the drum
When the laser has finished flashing points of light across the entire width of the OPC, the drum rotates - usually between 1/300th and 1/600th of an inch in most laser printers
Laser beam begins to work on the next line of dots
The drum rotates past the toner, which sticks to the charged points only
Paper is given an opposite charge and moved past the drum
Toner transfers to paper
Heated rollers fuse/melt toner into paper
Drum is scraped clean and discharged, ready for next page
Describe the charateristics of the Inkjet printer
Uses ink cartridges
Squirts tiny droplets of ink directly onto paper
Careful not to smudge the wet ink just after print
Black ink-jet printer contains one black ink cartridge and a colour ink-jet printer contains four ink cartridges (CYMK)
Describe the operation of the Inkjet printer
Print head moves sideways across the width of a sheet of paper
Ink-filled print cartridge/s are attached to the print head
Each cartridge is made up of 50, or more, ink-filled firing chambers
Each chamber is attached to a nozzle - thinner than a strand of human hair
At the bottom of all the chambers are thin resistors
When an electrical current flows through a resistor, the resistor heats a thin layer of ink at the bottom of the chamber to more than 900 degrees Fahrenheit for several millionths of a second
The ink boils and forms a bubble of vapor
As the vapor bubble expands, it pushes ink through the nozzle to form a droplet at the tip of the nozzle
The pressure of the vapor bubble forces the droplet of ink onto the paper
The volume of the ejected ink is about one millionth that of a drop of water from an eyedropper
A typical character is formed by an array of these drops 20 across and 20 high
As the resistor cools, the bubble collapses
The resulting suction pulls fresh ink from the attached reservoir into the firing chamber
Describe the characteristics of the flatbed printer.
Paper fixed to a flat bed Print head moves in X and Y axis on gantry Larger More expensive More accurate
Describe the charateristics of the Drum/Roller plotter
Paper moves in X axis on rollers
Printer head moves in Y axis
Print head uses felt pen/ink pen/inkjet
Describe the charateristics of the Dye sublimation printer
Heat the areas of a ribbon that are needed to form the letter
The heated ink transfers to specially coated paper or transparencies
Often used for photographs
Describe the Thermal Printer
Heat dye for transfer to paper
Do not require special paper
Most commonly used for sales receipts at service stations and supermarkets, and for fax machines
