Power and Printers

- computer uses DC voltage, most power sources provide AC voltage
- convert 120V AC or 240V AC to 3.3V DC, 5V DC, and 12V DC

- ampere(amp, A), rate of electron flow past a point in one second
- same flow as diameter of a hose
- voltage(volt, V), electrical pressure pushing the electrons
- how open the faucet is

- watt(W), measurement of real power use
- volts * amps = watts, 120V * 0.5A = 60W

- alternating current(AC), direction of current constantly reverses
- distributes electricity efficiently over long distances
- US/Canada: 110-120V of AC(VAC), 60Hz
- Europe: 220-240VAC, 50Hz
- direct current(DC), current moves in one direction with a constant voltage

- voltage varies by country, manually switch between 120V and 230V
- get a meter or use an auto-switching power supply
- don't plug a 120V power supply into a 230V power source

- different voltages for different components
- positive or negative voltage, a difference in potential
- 2nd floor = +10 feet, basement = -10 feet
- +12V, PCIe adapters, hard drive motors, cooling fans
- +5V, some motherboard components
- +3.3V, M.2 slots, RAM slots
- +5VSB, standby voltage, hibernate mode
- -12V, integrated LAN, older serial ports, some PCI cards
- -5V, legacy systems

- 2+ power supplies, internal to the server
- each power supply can handle 100% of the load, normally runs at 50% of the load
- hot-swappable, replace faulty power supply without powering down the server

- fixed connectors connected to the power supply, may have too many or not enough connectors
- can be modular, only use cables needed for better airflow, more expensive

- rated by watts, physical size is relatively standard
- older cases/systems may have proprietary sizes
- use online calculators to calculate total watts needed for all components: CPU, storage devices, video adapter, etc
- video adapters are usually the largest power draw
- 50% capacity is a good rule of thumb

- Multifunction devices
- printer, scanner, fax, network connection, phone line connection, print from web
- lot of things that can go wrong, going to need to fix them

specific to printer model, also get the right OS/OS driver

- Printer Command Language, created by Hewlett-Packard, commonly used across industry
- PostScript created by Adobe Systems, popular with high end printers
- make sure drivers match printer, PCL printer -> PCL driver

- USB type B is the most common connector
- USB type B on printer, USB type A on computer
- ethernet, RJ45 connector

- bluetooth, limited range
- 802.11 infrastructure mode, many devices using an access point
- 802.11 Ad hoc mode, no access point and direct link between wireless devices

- printer is connected to a computer that shares the printer
- computer needs to be running

jobs are managed on the printer, web-based front-end, client utility

- duplex option to print on both sides of the page to save paper
- not all printers have this option
- portrait vs landscape
- tray settings, printers can have multiple trays
- plain paper or letterhead, etc
- quality: resolution, color or greyscale, color saving mode

- user authentication can set rights and permissions
- badging allows job to not print until you authenticate using employee badge
- audit logs to manage/view cost management, security monitoring, and events
- may be built into printer or print server
- secure printing allow you to use a passcode at the printer

- all-in-one multifunction device and standalone flatbed
- may include an ADF(Automatic Document Feeder), scans multiple pages

- scan to email, sent to inboxes
- scan to folder using SMB, send to a microsoft share
- scan to cloud, cloud storage account, google drive, dropbox, etc

- combines a laser, high voltage, charged ions, powdered ink, heat, and paper
- high quality, fast printing speeds
- many moving parts, requires on-printer memory, messy on inside

- image is drawn onto a photosensitive drum, "painted" with a laser
- picks up and transfers toner to the paper
- can be separate from the toner cartridge or combined

heat and pressure, melts plastic toner powder and permanently bonds toner to paper

- color laser printer: cyan, yellow, magenta, black - 4 separate toner cartridges
- image is transferred from all cartridges to single belt then to a single transfer roller

- pickup paper, 1 page at a time
- problems if no paper or multiple sheets are picked
- should be periodically cleaned and replaced

- pull just the top sheet from paper tray
- small and inexpensive, easy to clean and replace

- printing on both sides, one side at a time
- need mechanisms to flip page automatically
- built-in or add-on

step 1: processing, build the entire page in memory
step 2: charging, prepare the drum with a negative electrostatic charge
step 3: exposing, write the image with the laser
step 4: developing, add negatively-charged toner to the imaging drum
step 5: transferring, move the toner from the drum to the paper
step 6: fusing, heat and pressure
step 7: cleaning, removing excess toner

- low doesn't mean empty
- toner may contain OPC(Organic Photoconductor) drum
- OPC is sensitive to light, make sure to keep it in the bag
- remove packing strips from the new drum and replace it with the old

- heat and pressure wear out moving parts
- standard kits include replacement feed rollers and new fuser unit
- check printer's page counter to know when to perform maintenance
- reset page counter after replaced

- varying densities with different toner cartridges, some dark and some light
- adjusts density to make it look perfect
- automated or manual process depending on printer

- printers are dirty as it accumulates dust
- use water, IPA(isopropyl alcohol)
- use a damp cloth for the outside
- for inside, don't use a normal vacuum cleaner or compressed air
- wash toner from skin with cold water and clean rollers with IPA

- ink dispersion, relatively inexpensive technology, high-res, and quiet
- expensive ink, proprietary, eventually fades, and clogs easily

- place drops of ink onto a page from a set of cartridges
- CMYK: cyan, magenta, yellow, black(key)

some consumer printers integrate the print head into the ink cartridge

- pick up and feed paper through the printer
- must be cleaned and maintained
- duplexing included with some printers

- ink cartridges are moved over the paper
- belt moves the carriage back and forth

- align nozzles to the paper, lines should be crisp and colors should align
- printers usually include a calibration option

- clogged heads from droplets of ink is a big issue
- many printers automatically clean every day
- output has streaks or sections of missing color
- some printers have a cleaning button or you can manually clean, easy process

- usually separate colors, some cartridges will combine
- takes seconds to replace, few minutes to calibrate and prepare cartridge
- recycle empty cartridges (plastic)

- lots of turns and twisted, jam is inevitable
- remove tray paper and any loose paper with firm pressure
- check and remove any scraps of paper

- white paper and/or clear tape, turns black when heated, no ink
- quiet/silent, paper is sensitive to light/heat

- long cylinder that holds the paper with friction
- gears on side that turn the cylinder and feed the paper through the printer

required to create output on thermal printer, doesn't move

- paper covered with a chemical, thermochromic paper, changes color when heated
- commonly seen in cash registers, credit card terminals

- relatively inexpensive, impossible to substitute
- replace exactly the right size
- easy replacement process, simple paper feed, small device

- IPA, cleaning pen, check manufacturer's recommendations
- swab gently on small areas
- use cleaning card to clean head and paper pathways

- small amount of paper bits and dust
- take thermal printer outside and blow it out using compressed air
- wipe it with damp cloth, avoid using vacuum

- more heat will darken the entire page
- avoid hot areas like car dashboard, radiator, hair dryers
- receipt will fade over time, don't use as archival media

- 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
- noisy, poor graphics

- made of fabric, one long ribbon, never ending circle
- single unit, easy to replace
- proprietary size, specific to printer model

- continuous paper feed, paper pulled through with holes on side of paper instead of friction
- holes have to line up perfectly

- replace when ink becomse too light,
- designed to be modular, replace in less than a minute

- a lot of abuse, replace entire print head, gets hot
- modular part, replace with the ribbon for best effect

- impact printer paper not as easy as a laser printer
- paper must feed perfectly into holes without constraint

- create a 3D item based on an electronic model
- additive manufacturing to build in layers and create the object, no machining process required
- rapid prototyping, design, create quickly, and inexpensive
- deploy designs anywhere in the world or into space

- FDM(Fused Deposition Modeling), melt filament to print 3D objects
- print a layer, move up, print another layer
- good all-around printer, larger print bed than resin printers
- easy to manage filament, minimum of mess, fewer disposal issues

- SLA(Stereolithography) 3D printing, smooth and finely detailed 3D prints
- resin is hardened using a light source with ultraviolet laser 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 local hazardous materials disposal

- flat adhesive surface, foundation of 3D print, everything builds on that first layer
- needs to be level and clean
- filament printing: printing surface, many different print bed options
- resin printing: bed is the location where resin is hardened by the UV light