Printers Getting it down on paper Impact

Printers Getting it down on paper

Impact Printers • Yes, they are still around and working! • Use a grid, or matrix, of printwires (pins) to push the inked ribbon into the paper (the impact) • Used for multipart forms (two or more copies) • When noise and print quality not important • Measured in characters per second (300 -500) • Use 9 -pin (Draft quality) or 24 -pin (Near letter quality) printhead

Characters for Impact • Bit-Mapped Font(s) – Put a dot here, put a dot there, … Whole chacacter described. Need one file for 10 -point, another for 12. • Mono-spaced fonts – each character gets the same width spacing • Most of the “thinking” is done by the computer not the printer

Inkjet Printers • Give the printer away, charge for ink Ink well Thermistor (Electroconductive Plates) nozzle This is NON-CONTACT printing

Inkjet (Print) Quality • Print Resolution – Dots per inch, more is better • Speed in pages per minute – with some undefined amount of characters – 8 to 15 • Cost of a set of cartridges can equal or exceed the printer’s cost • Quiet printing and color on the desktop • Need paper that will absorb ink dot – or not – for higher quality output

Math and Characters • A Vector has a starting point, a length and a direction. The printer is handed a vector and prints it as best it can. Independent of printer resolution. • Vector-based fonts (Postscript and True. Type); variable spacing for characters

Photo Printers • Dye Sublimation – heat up solid ink to vapor, transfer to paper, cool back to solid • Slip printers (at checkstands) a variation on this theme, but only black ink • Each dot is continuous tone (color on color) rather than closely spaced color dots (dithering)

Laser Printers • Classed as non-contact even though page is “ironed” at end of process • Higher speed than inkjet, lower per-page cost, longer duty cycle (more pages per month) • High voltage inside, and heat. Stay out! • If there is something wrong with the printer that changing the toner cartridge won’t fix, call a specialist.

Laser Printing • • Clean Charge Write Develop Transfer Fuse Clarence Carefully Wrote Down The Facts

Printing • Clean – Physical by wiping off residual toner from previous print cycle with rubber cleaning blade. Toner is recycled back to cartridge – Erase lamp brings the charge to neutral on the drum

Printing, cont. • Charge the drum – Primary corona wire writes a uniform negative charge (600 -1000 v) to surface of drum – Does not contact drum surface

Printing, cont. • Write the image – Laser is used to write a positive image (the black goes here) to drum – Laser striking drum creates low voltage spot on drum (~100 v)

Printing, cont. • Develop the image – Toner is attracted to low voltage areas of drum (produced by laser) – Toner (ink, plastic and iron mix) is now on drum

Printing, cont. • Transfer the image – Uses transfer corona wire – Charges paper with positive charge – attracts toner from drum to paper surface

Printing, done • Fusing – Pressure roller (on bottom) and heated roller (on top) melt toner into paper – Static eliminator brings page back to neutral charge

Electronics of Printing • Vector (True. Type) is converted to raster (series of dots) to commands for the laser • Raster Image Processor (RIP) used here. Usually this is your CPU’s task • Can get memory intensive so lasers ran out of memory for the page (Quark. Express is known for this)

Printer Port • Maximum data rate is 150 KBps with a lot of CPU cycles for standard port • IEEE 1284 standard defined parallel port modes, physical and electrical interfaces • Enhanced Parallel Port (EPP) – constant two-way communication with PC • Extended Capacity Port (ECP) – even faster communication

USB Printers • Most printers sold today can connect via USB • Need to install the drivers first, as with any USB device • Allows connection to Mac or PC

Network Printers • Share from one PC. PC has to be on, share it in the Printers Window • Print Server box. Box connects to network (Ethernet); printer connects to box (USB or parallel). • Standalone. Printer is its own device on network – wired or wireless

Fonts • Fonts, or Faces, are different ways to represent a character • Bangle Font – AIC is done this way • Bodoni Font • Century Gothic Font • Eurasia Font • French Script MT Font • Flatbrush Font

Printer Languages • ASCII – American Standard Code for Information Interchange. This is the core of printing. Additional information is in ASCII codes via “control codes” or “escape sequences” • Dot matrix printers have one, or more, built -in fonts; inkjet and lasers do not.

Printer Languages • Postscript. Developed by Adobe Systems. High resolution graphics and text – at a withering high license fee of $1000/printer • True. Type. Character “map” method that mostly gets around Post. Script. • Printer Control Language (PCL). HP’s route around Post. Script. Just characters

Setting Up a Printer • Plug in parallel cable (system off) then load drivers when Windows asks for them • Choose Add New Printer from Printers window for networked printer • Install drivers first, then plug in USB printer when the installer program requests it – USB cable usually extra purchase item

Printers and Devices • The Printer is a program that controls one (or more) print devices • The Printer includes the print driver and print spooler • So… you install the printer and connect the print device(s)

Troubleshooting Lasers • Clean – if not, you will get random spots on pages • Charge – if not, you will get random white areas on the page • Write – if not, little or nothing written to page • Develop – again, blank (white) spots on page at repeated intervals down page • Transfer – banded section of white where text should be • Fuse – toner will fall off the paper. This is only issue that replacing the toner cartridge will not fix. • A scratch on the drum will produce vertical lines on the page

And More • Check the Print spooler if print jobs do not come out. A ‘sticking’ print job will hold up following print jobs.

Multiple Printers • On one port need a switchbox (single in, selectable out). Don’t use mechanical switchbox with laser printers • On multiple ports, use the Print dialog box to select printer • Selected printer does not have to be default printer

Dot Matrix Printers • Vacuum out, or blow out, paper “dander” • Keep platten clean – use alcohol • Avoid the urge to clean printhead – you will make a mess of it and shorten its life • Replacing a printhead that has failed is about 2/3 the cost of new printer

Laser Printers • Again, if replacing the toner cartridge does not solve the problem, call a specialist • Comp. TIA wants you to vacuum the printer each time you change toner

Inkjet printers • Best maintenance is to use the printer • Clean printhead to remove streaks, but it uses ink • Finding the maintenance options window can be a real challenge

Scanners • Flatbed scanners – most common type; place a photo/document on the glass; run scanner software either from front panel of scanner or on computer – but not both! • Creates an image/picture – have to use Optical Character recognition software to “convert” to a text document • TWAIN driver – Technology without an interesting name

Picking a scanner • Dedicated device: most pick based on price – more expensive means more control over scan • Resolution: how many pixels/dots per inch, 2400 x 2400 is good place to start • Color depth: how accurate the colors will be (like video); 24 - and 48 -bit depth; also affects resulting file size

More Scanner • Grayscale depth – how many shades of gray per pixel; 8 -, 12 - and 16 -bit • Scanning speed – part of it you set when you select above items – from seconds to minutes

Installing a Multifunction Device • Most connect via USB or wirelessly, so you need to consider connectivity • Need to install drivers for each function • Can get messy with outdated drivers; manufacturers often add absurdly bad “applications” (think HP) • Complex machine that can break in interesting ways…

Installing a Local Printer • Use this option for the printer connected to your computer, or a standalone network printer using an IP address • Michael thinks Windows will automatically detect and install drivers for USB printer • I prefer the disk that came with the printer (have disk option) • Default printer is the one used most of the time

Troubleshooting Printers • Make sure it is on, online, has paper and there is not a error in the print queue

Restarting the Spooler • Right-click Computer; select Manage; click Services and Applications; then Services • Find Print Spooler Service; stop and restart it

Consumables • Don’t just throw toner, ribbons, ink cartridges away – recycle them • Some companies will pay for toner cartridge • Good idea to clean printer when you change out consumables