3.7 Printers Flashcards
- 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
Laser Printer
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
Imaging drum
In Laser Printer,
- Heat and pressure - Melt plastic toner powder
– Permanently bond toner to paper
Fuser assembly
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
Transfer belt and roller
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
Pickup rollers
In Laser Printer,
- Pull just the top sheet from the paper tray
– Not multiple sheets - Small and inexpensive - Easy to clean or replace
Separation pad
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
Duplexing assembly
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
Imaging drum
Main Component that creates the image to be applied to the paper.
Imaging drum
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
Imaging drum
Bitmap of the final page is stored in memory.
Build the entire page in memory
Step 1. Processing the image:
Drum surface is charged to -600 V.
Prepare the drum with a negative electrostatic charge
Step 2. Charging or conditioning:
Laser beam writes -100 V image to drum surface.
Write the image with the laser
Step 3. Exposing or writing:
Toner is applied to the surface of the drum.
Add toner to the charged areas of the imaging drum
Step 4. Developing:
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
Step 5 . Transferring:
Fuser assembly uses heat and pressure to fuse toner to paper.
Heat and pressure
Step 6. Fusing:
Drum is cleaned of residual toner and charge.
Remove excess toner
Step 7. Cleaning:
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
Replacing the toner cartridge
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!
Laser printer maintenance kit
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
Replacing the toner cartridge
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
Laser printer cleaning
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
Laser printer calibration
- Relatively inexpensive technology
- Quiet
- High-resolution
- Expensive ink
– Proprietary - Eventually fades
- Clogs easily
Inkjet (ink-dispersion) printer
In Inkjet Printer,
- Place drops of ink onto a page
– Pulled from a set of cartridges - CMYK - Cyan, Magenta, Yellow, Key (black)
Ink cartridge
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
Print head
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
Feed rollers
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
Carriage and belt
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
Inkjet printer calibration
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
Cleaning print heads
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
Replacing inkjet cartridges
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
Inkjet printer calibration
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
Clearing jams
- White paper
– Turns black when heated
– No ink! - VERY quiet
– Almost silent - Paper is sensitive to light and heat
– And clear tape
Thermal printer
In Thermal printer .
- Full-length heating element
– No moving print head
Heating element
In Thermal printer ,
- Pull paper through the printer
– Relatively small paper path
Feed assembly
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
Thermal paper
- 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
Dot-matrix (impact) printers
In Dot-matrix (impact) printers,
- Fabric
– One long ribbon - Never ending circle - Easy to replace - Once single unit
- Proprietary size - Specific to printer model
Printer ribbon
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
Tractor feed
In Dot-matrix (impact) printers,
- Moves back and forth
– Pins hit ribbon and paper - One matrix - Must move across the page to print
Dot-matrix printer head
- “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
3D printers
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
Filament printing
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
Resin printing
- 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
The print bed
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
Print head replacement
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
Printer ribbon replacement
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
Replacing paper
