EET 450 – Advanced Digital Printers, Plotters and other hard copy output devices.
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Transcript of EET 450 – Advanced Digital Printers, Plotters and other hard copy output devices.
Printers
The object is to get ‘hard copy’ output from the computerOutput is in a variety of forms Letters/numbers Graphics
Printers
The competition is speed versus quality (and price) Speed determined by Characters per
Second (cps) or Pages per Minute (ppm)
Quality is measured by a variety of factors Dots per inch (dpi) ‘Letter Quality’
Printing Engines
Historically, printers were fabricated from typewriter mechanismsDot Matrix Characters are constructed using
‘dots’ of ink or other marks Typically a 5x7 matrix at least
Printing Engines
‘Letter Quality’ Originally used to describe output of
the quality of a professional letter Impact LQ printers use ‘Letter at
once’ technology Laser and Ink Jet printers now have
high enough quality to be determined as LQ
Printing Engines
Line Printer Prints an entire line of print at one
time Used for ‘High Volume’ output
Color versus Monochrome Available in each of the above
technologies +
Printer types
Impact Dot Matrix Uses a set of magnet actuated wires
(pins) which strike a ribbon, leaving the imprint of the character as an array of dots
Ribbons may be in a variety of (primary) colors, allowing color output.
Printer types
Ink Jet (dot matrix) Thermal Inkjet – uses pigment
bearing ink heated to steam – which is emitted to form characters
Piezo Inkjet – uses piezo crystal actuator to ‘spray’ a liquid ink
Printer types
Phase Change Inkjet – wax based inks Electrostatic Inkjet – ink droplets are
charged/propelled by electrostatics
Thermal & electrostatic Printers Use thermally reactive paper darkens
when a very small heating element is activated
Electrostatic discharge into coated paper, burns dots into the surface of electrostatic printers
Printer types
Laser printers Image is ‘written’ using a laser LED, onto an
electro statically charged surface A powdered, pigment bearing, ‘toner’ is
adhered to the surface by the charge The image is transferred to paper, by
pressing the powdered image to the surface The powdered toner is fused (heated) to the
paper by a heating element, at the same time it is pressed into the surface of the paper.
Voila
Printer Types
Thermal Transfer Pigment is carried on a ribbon, and
melted to the paper by an element – a form of DM
Dye Diffusion/Dye sublimation High quality – photo output Similar to thermal transfer, but using
penetrating dyes
Paper handling
Sheet Feeders Most printers now use some form of
cut sheet feeder to supply paper to the mechanism
Friction feed/continuous paper Use a roller, pressing into the platten
to feed a continuous roll of paper Not very accurate
Paper handling
Pin Feed Generally describes a set of pins, at the
sides of the platten Requires ‘tractor feed’ paper
Tractor Feed Using the holes in ‘tractor feed’ paper,
PULLS the paper from the head area or pushes the paper into the head area
Paper handling
Duplex printing Usually only available in laser printers A complex mechanical mechanism, reverses
the paper from output back to feed into the printer.
Both sides of the paper are used
Form feeders Alternate paper bins Envelope feeders
Paper
Quality of paper is measured by Weight - pounds per 500 sheet ream
of uncut C size paper Or per 2000 8.5”x11” sheets
Brightness Ie 84 - % of light reflected from the
surface
Papers
Coating/specialty papers High quality – photo quality Canvas/other surfaces Transparencies Cloth Card stock, etc.
Other output devices
3D – output Photo lithography
Rapid prototyping technique UV Curable resin used to ‘build’ a 3
dimensional image Milling
Material is removed to leave the 3D image
CAD