3.7 Printers

Question 1

• Combine a laser, high voltage, charged ions,
  powdered ink, heat, and paper
• Very high quality
• Fast printing speeds
• Very complex, many moving parts, requires on-printer memory and messy on the inside

Answer 1

Laser Printer

Question 2

In Laser Printer,
* Image is drawn onto a photosensitive drum
– “Painted” with a laser
* Picks up toner - Transfers toner to the paper
* Can be separate from the toner cartridge or combined

Answer 2

Imaging drum

Question 3

In Laser Printer,

• Heat and pressure - Melt plastic toner powder
  – Permanently bond toner to paper

Answer 3

Fuser assembly

Question 4

In Laser Printer,

Color laser printers
– Cyan, yellow, magenta, black
* Four separate toner cartridges
* Image is transferred from all cartridges to the single belt
– And then to a single transfer roller

Answer 4

Transfer belt and roller

Question 5

In Laser Printer,

• Pickup paper - Should be a single page at a time
  – Problems if no paper is picked up
  or multiple sheets are picked
• Should be periodically cleaned or replaced

Answer 5

Pickup rollers

Question 6

In Laser Printer,

• Pull just the top sheet from the paper tray
  – Not multiple sheets
• Small and inexpensive - Easy to clean or replace

Answer 6

Separation pad

Question 7

In Laser Printer,

• Printers usually print on a single side
  – Not both sides simultaneously
• Printing on both sides is a two step process
  – Print side one, print side two
• You need mechanisms to “flip” the page
  – Automatically
• Can be built-in to the printer
• Or available as an add-on

Answer 7

Duplexing assembly

Question 8

Image is drawn onto a photosensitive drum
– “Painted” with a laser
Picks up toner - Transfers toner to the paper
Can be separate from the toner cartridge or combined

Answer 8

Imaging drum

Question 9

Main Component that creates the image to be applied to the paper.

Answer 9

Imaging drum

Question 10

How laser printers work ?
1) Toner is placed on electrically charged rotating drum called the___
2) Toner is transferred onto paper as it moves through the system

Main Component that creates the image to be applied to the paper

Answer 10

Imaging drum

Question 11

Bitmap of the final page is stored in memory.

Build the entire page in memory

Answer 11

Step 1. Processing the image:

Question 12

Drum surface is charged to -600 V.
Prepare the drum with a negative electrostatic charge

Answer 12

Step 2. Charging or conditioning:

Question 13

Laser beam writes -100 V image to drum surface.

Write the image with the laser

Answer 13

Step 3. Exposing or writing:

Question 14

Toner is applied to the surface of the drum.

Add toner to the charged areas of the imaging drum

Answer 14

Step 4. Developing:

Question 15

The transfer roller puts a positive charge on the paper to pull the toner from the drum and onto the paper.

Move the toner from the drum to the paper

Answer 15

Step 5 . Transferring:

Question 16

Fuser assembly uses heat and pressure to fuse toner to paper.
Heat and pressure

Answer 16

Step 6. Fusing:

Question 17

Drum is cleaned of residual toner and charge.

Remove excess toner

Answer 17

Step 7. Cleaning:

Question 18

During Laser Printer Maintenance,

• Look for the messages
  – Low doesn’t mean empty
• The toner can also contain the OPC drum
  – Organic Photoconductor drum
  – Sensitive to light; keep it in the bag
• Power down the printer
  – Safety first
• Remove packing strips from the new drum
  – Replace it with the old

Answer 18

Replacing the toner cartridge

Question 19

During Laser Printer Maintenance,
* Laser printers wear out
– All those moving parts
– Heat and pressure
* Standard maintenance kits
– Replacement feed rollers, new fuser unit, etc.
* When to perform maintenance?
– Check the printer’s page counter
* Power down and replace the components
– Fuser units are HOT
* Reset the page counter when you’re done!

Answer 19

Laser printer maintenance kit

Question 20

During Laser Printer Maintenance,

• Look for the messages
  – Low doesn’t mean empty
• The toner can also contain the OPC drum
  – Organic Photoconductor drum
  – Sensitive to light; keep it in the bag
• Power down the printer - Safety first
• Remove packing strips from the new drum
  – Replace it with the old

Answer 20

Replacing the toner cartridge

Question 21

During Laser Printer Maintenance,

• Laser printers are dirty - All that toner and paper dust
• Check the manufacturer’s recommendations
  – Water, isopropyl alcohol (IPA)
  – Don’t use harsh chemicals!
• Outside - Damp cloth
• Inside - Wipe dust away
  – Don’t use a normal vacuum cleaner or compressed air
  – Wash off skin with cold water
  – Clean rollers with IPA

Answer 21

Laser printer cleaning

Question 22

During Laser Printer Maintenance,

• Different toner cartridges print with different densities
  – Some dark, some light
• Laser printer calibration can adjust the density
  – Makes it looks perfect
• Can be automated or a manual process
  – Every printer is different
  – Check the printer manual

Answer 22

Laser printer calibration

Question 23

• Relatively inexpensive technology
• Quiet
• High-resolution
• Expensive ink
  – Proprietary
• Eventually fades
• Clogs easily

Answer 23

Inkjet (ink-dispersion) printer

Question 24

In Inkjet Printer,

• Place drops of ink onto a page
  – Pulled from a set of cartridges
• CMYK - Cyan, Magenta, Yellow, Key (black)

Answer 24

Ink cartridge

Question 25

In Inkjet Printer, * Some consumer printers integrate the print head into the ink cartridge – Change the cartridge, get a new print head * Others separate the ink cartridge from the print head

Answer 25

Print head

Question 26

In Inkjet Printer, * Pick up and feed paper through the printer – Must be clean and not worn * Duplexing – Print on both sides of the paper – Included with some printers

Answer 26

Feed rollers

Question 27

In Inkjet Printer, * Ink cartridges are moved over the paper – Carriage may include its own print head * Belt moves the carriage back and forth – Another moving part

Answer 27

Carriage and belt

Question 28

In Inkjet Printer, * Align nozzles to the paper – Lines should be crisp – Colors should align * Printer includes a calibration option – May need to make minor adjustments

Answer 28

Inkjet printer calibration

Question 29

During Inkjet Printer Maintenance, * Small droplets of ink - And small holes in a print head * Clogged heads is a big issue – Many printers automatically clean every day – Output has streaks or sections of missing color * Cleaning process can be started manually – Only takes a few minutes * Some print heads/cartridges can be removed – Manually cleaning may help

Answer 29

Cleaning print heads

Question 30

During Inkjet Printer Maintenance, * Usually separate colors – Cyan, Magenta, Yellow, and Key (CMYK) – Some cartridges will combine these * Takes seconds to replace – Takes a few minutes to calibrate and prepare the cartridge * Recycle the empty cartridge - All plastic

Answer 30

Replacing inkjet cartridges

Question 31

During Inkjet Printer Maintenance, * Align nozzles to the paper – Lines should be crisp – Colors should not overlap * Printer includes a calibration option – May need to make minor adjustments

Answer 31

Inkjet printer calibration

Question 32

During Inkjet Printer Maintenance, * Lots of turns and twists – A jam is inevitable * Remove tray paper – Any loose paper * Remove paper from the path – Firm pressure, don’t rip * Check for any scraps of paper * Remove all loose paper

Answer 32

Clearing jams

Question 33

* White paper – Turns black when heated – No ink! * VERY quiet – Almost silent * Paper is sensitive to light and heat – And clear tape

Answer 33

Thermal printer

Question 34

In Thermal printer . * Full-length heating element – No moving print head

Answer 34

Heating element

Question 35

In Thermal printer , * Pull paper through the printer – Relatively small paper path

Answer 35

Feed assembly

Question 36

In Thermal printer , * Paper covered with a chemical – Changes color when heated * Cash registers, credit card terminals – And quiet areas * Looks like normal paper – Feels a bit different

Answer 36

Thermal paper

Question 37

* Print head with a small matrix of pins – Presses against a ribbon to make a mark on paper * Good for carbon/multiple copies * Low cost per page * NOISY * Poor graphics * Relatively niche use cases

Answer 37

Dot-matrix (impact) printers

Question 38

In Dot-matrix (impact) printers, * Fabric – One long ribbon - Never ending circle * Easy to replace - Once single unit * Proprietary size - Specific to printer model

Answer 38

Printer ribbon

Question 39

In Dot-matrix (impact) printers, * Paper pulled through with holes on the side of the paper – Instead of using friction * Continuous paper feed – Perforations between pages * Holes have to line up perfectly – Tractor paper can be perforated to remove holes

Answer 39

Tractor feed

Question 40

In Dot-matrix (impact) printers, * Moves back and forth – Pins hit ribbon and paper * One matrix - Must move across the page to print

Answer 40

Dot-matrix printer head

Question 41

* “Print” in three dimensions – Create a 3D item based on an electronic model * Additive manufacturing – Build in layers to create the object – No machining process required * Rapid prototyping – Design and create relatively quickly and inexpensively * Deploy designs anywhere in the world – Or into space

Answer 41

3D printers

Question 42

In 3D printers, * Fused Deposition Modeling (FDM) – Melt filament to print 3D objects – This is probably the printing type you’ve seen * Print a layer, move up,print another layer – Watch the printer create the object * Good all-around printer – Larger print bed than resin printers – Easy to manage filament – Minimum of mess – Fewer disposal issues

Answer 42

Filament printing

Question 43

In 3D printers, * Stereolithography (SLA) 3D Printing – Smooth and finely detailed 3D prints * Resin is hardened using a light source – Ultraviolet light or a laser – Layers are added to the bottom – Entire print hangs from the build platform * Resin must be handled properly – Wear protective gear – Take unused resin to your local hazardous materials disposal

Answer 43

Resin printing

Question 44

* A flat adhesive surface – The foundation of a 3D print – Everything builds on that first layer * Needs to be level and clean – Prints “stick” to the bed * Filament printing – The print bed is the printing surface – Many different print bed options * Resin printing – The “bed” is the location where the resin is hardened by the UV light

Answer 44

The print bed

Question 45

During Impact Printer Maintenance. * Takes a lot of abuse - Directly hits the ribbon and paper * Gets hot - Watch your fingers – Another modular part - Look for a release lever or bar * Replace with the ribbon for the best effect – The output should look perfect

Answer 45

Print head replacement

Question 45

During Impact Printer Maintenance. * Single ribbon – Self-contained - One long circle * Replace when ink becomes too light – Ink is eventually consumed * Designed to be modular - Replace in less than a minute

Answer 45

Printer ribbon replacement

Question 46

During Impact Printer Maintenance. * Not as easy as a laser printer – Paper must feed perfectly into holes – Tractor feed * Forms must be positioned correctly – Text needs to fit a predefined space * Paper must feed without constraint * Make sure nothing is in the way

Answer 46

Replacing paper